CN101248706B - Electric device and heating cooking device - Google Patents

Abstract

The present invention can prevent electric leakage and electric shock and reduce power consumption during standby mode. The electric appliance includes an appliance main body (1) utilizing an AC power supply, and a power supply unit (6) arranged on the appliance main body (1), the power supply unit (6) is connected to the AC power supply as an input power supply and outputs DC and AC as power supplies to the appliance body (1). The power supply unit (6) includes a power supply circuit (7) for converting input AC power into DC power electrically isolated from the AC power, relays (8a, 8b) for switching on and off the supply of AC power to the appliance body (1), and A leakage detection circuit (10) arranged between a relay contact and an appliance body (1) cuts off a relay (8a, 8b) when a leakage in the appliance body (1) is detected. Therefore, when there is a leakage in the appliance body (1), the leakage detection circuit (10) cuts off the relays (8a, 8b) to stop the AC power supply to the appliance body (1), thereby preventing accidents caused by the leakage. Also, in standby mode, the relays (8a, 8b) are turned off to reduce power consumption.

Description

Electrical appliances and heating and cooking equipment

technical field

The present invention relates to an electric appliance capable of reducing power consumption when in a standby mode, and in particular, a safety device capable of preventing electric leakage or electric shock of the electric appliance. Furthermore, the present invention relates to an electric appliance capable of reducing electric power consumption in a standby mode, and in particular, a safety device capable of preventing electric leakage or electric shock of a cooking apparatus using water and/or generating steam.

Background technique

Conventionally, in electric appliances such as microwave ovens, when ground terminals are provided in the main bodies of these microwave ovens, the ground terminals are grounded during operation to avoid the risk that users may suffer from electric shock failures. In addition, there are some microwave ovens equipped with an earth leakage cutoff function, assuming that the ground terminal equipped with the main body of the microwave oven is not firmly grounded.

Fig. 11 shows a circuit diagram of the above microwave oven. As shown in FIG. 11 , the microwave oven is composed of a magnetron 104 , a control board 106 , a relay 107 , and a zero-phase converter 108 . The magnetron 104 is oscillated by a power source including a high voltage converter 101 , a capacitor 102 , and a diode 103 . The operation control board 106 receives power supplied from the low-voltage inverter 105 . The relay 107 opens and closes the connection between the power source and the high voltage converter 101 . Zero-phase converter 108 is provided on the power supply line between the power supply and relay 107 . Since the relay 107 operates to receive a control signal supplied from the control board 106 to supply power to the high voltage inverter 101, the magnetron 104 oscillates to heat food. In addition, the control board 106 monitors the unbalanced current detected by the zero-phase current transformer 108 in order to detect electric leakage. When electric leakage is detected, the control board 106 immediately turns off the relay 107 so as to cut off the electric leakage current (refer to Patent Publication 1).

Patent Publication 1: JP-A-58-175282

Contents of the invention

The problem to be solved by the present invention

However, in the conventional layout of the microwave oven, since the low-voltage converter 105 is installed on the control board 106, there is a problem that the leakage cut-off function cannot be effectively realized for the leakage caused by insulation aging in the control board 106. In addition, in recent years, when microwave ovens equipped with an oven function are mainly sold, relays for turning on/off the heater, etc. are further arranged on the control board, thus complicating the control board itself And become large size. As a result, a higher cost is required compared to the cost of a conventional microwave oven in order to improve the insulation performance of the control board itself.

And, recently, it is generally necessary to suppress the standby power of the microwave oven to 1W (Watt) or less. In addition, in a microwave oven not equipped with a clock function, it is required to reduce its standby power to 50mW (milliwatts) or below, that is, various ideas have tried to solve the need to make the standby power roughly close to zero power . In the conventional arrangement described above, electric power is continuously supplied to a circuit equipped on a control board for detecting electric leakage. Therefore, even the power consumed in the detection circuit itself cannot be ignored. In addition, since a circuit for detecting electric leakage is also operated, there is another problem that the standby power can hardly be suppressed to be lower than or equal to 50 mV. In addition, there is another problem that, in an electric appliance using metal as its casing, when a leakage occurs between the control board and the metal part of the casing, the leakage cannot be avoided unless the power outlet is unplugged.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an electric appliance equipped with a safety device capable of preventing electric leakage or electric shock. In addition, another object of the present invention is to provide a heating cooking device equipped with a safety device capable of preventing electric leakage or electric shock and capable of reducing power consumption in a standby mode.

means of solving problems

In order to solve the above-mentioned conventional problems, an electric appliance according to the present invention comprises: an appliance body applying an AC (alternating current) power supply; and a power supply unit to which an AC power supply provided in the appliance main body is connected as an input power supply, Outputting a DC voltage and an AC voltage to the appliance body as a supply voltage; wherein the power supply unit includes: a power supply circuit that converts the input AC supply voltage into a DC supply voltage electrically isolated from the AC supply; and starting or stopping the AC supply voltage to the appliance body supplied relays.

As a result, since the AC voltage supply to the appliance body can be stopped, the relay is cut off so that the AC power can be cut off from the appliance body except the power supply unit.

In addition, the power supply unit of the electric appliance of the present invention is equipped with a leakage sensing circuit provided between the terminal of the relay and the appliance body for detecting leakage occurring in the appliance body to cut off the relay.

Thus, when electric leakage occurs in the appliance main body, the electric leakage sensing circuit turns off the relay so as to stop the AC voltage supply to the appliance main body. As a result, failures caused by electric leakage can be avoided in advance.

Furthermore, the appliance of the present invention cuts off the relay when the appliance is in standby mode.

As a result, the power to turn on the relay can be eliminated, so that unnecessary power consumption of electric appliances can be eliminated.

In addition, in the standby mode in which the electric appliance is not used by the user, AC voltage is not applied to unnecessary parts of the appliance main body, thereby making the operation safer.

In addition, the electric appliance of the present invention is equipped with a control unit that controls the electric appliance; the control unit operates to receive DC voltage applied from the power supply unit to operate, and controls the supply of DC voltage to the relay and the leakage sensing circuit.

Thus, the DC voltage of the leakage sensing circuit can be applied to reduce unnecessary power consumption when turning on a relay with a high possibility of occurrence of leakage in the appliance main body.

In addition, the control unit of the electric appliance of the present invention stops the DC voltage supply to the relay and the electric leakage sensing circuit when the electric appliance is in the standby mode.

Thus, in a standby mode that does not require an AC voltage, it is possible to stop the DC voltage to the relay and the leakage sensing circuit in order to reduce unnecessary power consumption.

Furthermore, the power supply unit of the electric appliance of the present invention is provided with a noise filter circuit on the input side of the AC power supply, and the power supply unit is provided as a single unit.

Thus, since the part which cannot detect the occurrence of electric leakage can be incorporated into the power supply unit, the risky aspect of electric leakage occurring in the power supply unit can be considerably improved, so that the safety of the entire electric appliance can be improved.

And, the heating and cooking apparatus according to the present invention comprises: a load; a control device for controlling the load; a power supply unit for the control device; a power supply unit for supplying power from the power supply unit to the control device; An initial signal generation unit for power supply; a wire that supplies commercial power supply voltage to both the load and the power supply unit; a current detection unit that detects an unbalanced current flowing through the wire; and based on the signal output from the current detection unit, judges whether there is a leakage current A leakage judging unit; wherein, when the power supply unit does not supply power in the standby mode, the supply of the power supply voltage is started in response to the signal of the initial signal generating unit, so that the control device and the leakage judging unit start their operations; in addition, if the leakage judging If the signal of the unit is normal, then continue the power supply of the power supply unit so as to continue the subsequent operations of the control device and the leakage judgment unit, and in addition, the power supply unit stops supplying power.

Thus, since the power supply to both the control device and the electric leakage judgment unit is stopped in the standby mode, power consumption in the control device and the electric leakage judgment unit can be eliminated.

In addition, the control device of the heating and cooking equipment of the present invention includes a power switch with a reset function for disconnecting/closing the connection between the load and the power supply unit; and, when the signal of the leakage judgment unit is abnormal, the control The device disconnects the power switch.

Thus, even if a leakage occasionally occurs in the power supply unit or the control device, the switching device can be turned off to stop the power supply. As a result, electric shock can be avoided.

In addition, the electric appliance according to the present invention comprises: a load; a control device controlling the load; a wire supplying power supply voltage to both the load and the control device; a current detection unit detecting an unbalanced current flowing through the wire; A signal for judging the presence or absence of a leakage current judging unit; a main switching device for disconnecting/closing the electric wire; and a switch connected in parallel with the main switching device; wherein, in the standby mode where the main switching device is disconnected, the switch is closed to start the power supply supply voltage so that the control device starts its control operation; when the leakage judging device judges that no leakage has occurred, since the control device closes the main switching device, even if the switch is turned off, the subsequent operation of the control device can be continued, and the control device is disconnected. Turn on the main switchgear to change to standby mode.

Thus, since the power supply to the control device is stopped in the standby mode, power consumption in the control device can be eliminated. In addition, even if an occasional leakage occurs in the load or control device, electric shock can be avoided due to the cut-off of the main switching device.

In addition, the electrical appliance of the present invention is equipped with a notification device; and, when the leakage judging device judges that a leakage occurs, the control device notifies and turns off the main switchgear.

Thus, the electric appliance can notify the user of the fact that the electric leakage has occurred.

In addition, the electrical appliance of the present invention is equipped with a storage device and a notification device; and, when the leakage judging device judges that a leakage occurs, the control device stores the leakage information in the storage device, and in addition, even if the leakage judging device judges that no leakage occurs, it can notify Leakage information stored in a memory device.

Therefore, since the operation mode in which the leakage occurs can be stored in the memory device, this operation mode can provide clues for repairing the place where the leakage occurs.

In addition, the electric appliance of the present invention is equipped with a microcomputer; and, the microcomputer is equipped with a check program for operating a load connected to the electric wire in a predetermined state so as to check whether the judgment made by the leakage judgment device is normal, and the microcomputer performs the check by a predetermined operation program.

Thus, the electric appliance can confirm the presence or absence of electric leakage in all the loads coupled to the electric wires by a simple operation.

Advantages of the invention

The electric appliance of the present invention is equipped with safety equipment capable of preventing electric leakage or electric shock, and can reduce power consumption when the electric appliance is in standby mode.

Brief description of the drawings

1 is an external view of a microwave oven according to a first embodiment of the present invention;

2 is a circuit diagram of a microwave oven according to a first embodiment of the present invention;

3 is an external view of a heating and cooking device according to a second embodiment of the present invention;

4 is a circuit diagram of a heating and cooking device according to a second embodiment of the present invention;

Fig. 5 (a) is to represent under the second embodiment of the present invention, when the door is opened or closed in standby mode, the timing diagram of the voltage of each part of initial signal generation unit; And Fig. 5 (b) is to represent when Timing diagram of the voltages of the various parts of the initial signal generation unit when the ON/OFF logic state of the gate switch is reversed;

6 is a circuit diagram of a heating and cooking device according to a third embodiment of the present invention;

7 is an external view of a microwave oven according to a fourth embodiment of the present invention;

8 is a circuit diagram of a microwave oven according to a fourth embodiment of the present invention;

9 is a circuit diagram of a microwave oven according to a fifth embodiment of the present invention;

10 is a circuit diagram of a microwave oven in which a main switching device is provided on a wire to a control device according to a sixth embodiment of the present invention; and

Fig. 11 is a circuit diagram of a conventional microwave oven.

Designation and Symbol Description

1 appliance body

2 power cords

3 ground terminal

4 ground wire

5AC power supply

6 power supply unit

8a, 8b relay

9 noise filter circuit

10 leakage sensing circuit

11 control unit

12 switches

13 resistors

14 transistors

15 converters

16 zero-phase current converter

17 judgment circuit

1008a wire

1010a high frequency generator (load)

1010b heater (load)

1011a, 1011b, 1011c, 1011d relay (switching device)

1013 microcomputer (control device)

1014 AC/DC converter (power supply unit)

1015 zero-phase current transformer (current detection unit)

1016 leakage judgment unit

1017 power supply voltage application unit

1019 initial signal generation unit

1020 door switch

1025 power switch

2004 display unit (notification device)

2009a wire

2010, 2025 relay (main switch)

2012 High frequency generator (load)

2013 Control Device

2015 microcomputer

2016 memory device

2018 Zero Phase Current Converter (Current Detector)

2019 leakage judgment device

2010 switch

2022 heater (load)

Detailed ways

The first invention is an electric appliance comprising: an appliance main body to which an AC power source is applied; and a power supply unit to which an AC power supply provided in the appliance is connected as an input power source, and which outputs a DC voltage and an AC voltage to the the appliance body as the supply voltage; wherein the power supply unit comprises: a supply circuit for converting an input AC supply voltage to a DC supply voltage electrically isolated from the AC supply; and for starting and stopping the AC supply to the appliance body Voltage supply relay. As a result, since the AC voltage supply to the appliance body is stopped, the relay is cut off, so that the AC power can be cut off from the appliance body except the power supply unit, thereby making the operation safer.

More specifically, in the second invention, the power supply unit of the first invention is provided with a leakage current sensing circuit provided between the contacts of the relay and the appliance main body for detecting occurrence of of leakage current in order to cut off the relay. Thus, when electric leakage occurs in the appliance main body, the electric leakage sensing circuit turns off the relay so as to stop the AC voltage supply to the appliance main body. As a result, failures caused by electric leakage can be avoided in advance.

More specifically, in the third invention, the electric appliance of the second invention cuts off the relay when the electric appliance is in the standby mode. As a result, the power to turn on the relay can be eliminated, so that unnecessary power consumption of electric appliances can be eliminated. In addition, in the standby mode in which the electric appliance is not used by the user, AC voltage is not applied to unnecessary parts of the appliance main body, thereby making the operation safer.

Especially, in the fourth invention, the appliance main body of the second invention is equipped with a control unit for controlling electric appliances, and the control unit operates to receive the DC voltage applied from the power supply unit, and to control both the relay and the electric leakage sensing circuit. The on/off of the DC voltage supply of the other. Thus, when a relay with a high possibility of leakage occurring in the appliance main body is turned on, the DC voltage of the leakage detection circuit can be started, so that unnecessary power consumption can be reduced.

More specifically, in the fifth invention, when the electric appliance is in the standby mode, the control unit of the fourth invention cuts off the DC voltage supply to both the relay and the electric leakage sensing circuit. Thus, in a standby mode that does not require an AC voltage, the DC voltage to both the relay and the leakage sensing circuit can be stopped, so that unnecessary power consumption can be reduced.

More specifically, in the sixth invention, the power supply unit of the second invention is equipped with a noise filter circuit on the input side of the AC power supply, and the power supply unit is provided as a single unit. Thus, since the part that cannot detect the occurrence of electric leakage is incorporated into the power supply unit, the risky aspect of electric leakage occurring in the power supply unit can be considerably improved, so that the safety of the entire electric appliance can be improved.

A seventh invention is a heating and cooking apparatus comprising: a load; a control device controlling the load; a power supply unit of the control device; a power supply unit supplying power from the power supply unit to the control device; an initial signal generating unit that applies a signal to the power supply unit to start power supply; applies a commercial power supply voltage to electric wires of both the load and the power supply unit; detects an unbalanced current flowing through the electric wires a current detection unit; and an electric leakage judging unit judging whether there is an electric leakage based on a signal output from the current detecting unit; wherein, in a standby mode in which the electric power supply unit does not supply electric power, in response to a signal of the initial signal generating unit starting the supply of a power supply voltage so that the control device and the electric leakage judging unit start their operations; and, wherein, if the signal of the electric leakage judging unit is normal, then continuing to perform the power supply of the electric power supply unit, thereby Subsequent operations of the control device and the electric leakage judging unit are continued, and furthermore, when electric leakage does not occur, power supply of the electric power supply unit is stopped, however, no forward operation is performed for a predetermined time. As a result, power consumption in both the control device and the leakage judgment unit can be eliminated, thereby reducing power consumption in the standby mode.

More specifically, in the eighth invention, when a door switch cooperating with opening/closing operation of the door is provided in the initial signal generating unit of the seventh invention, the signal is generated by opening or closing the door switch. As a result, when the material to be cooked is heated while the power-on switch is not applied, the power supply performs the necessary opening/closing operation of the door so that user-friendly functions are not impaired.

More specifically, in the ninth invention, the heating and cooking apparatus of the seventh invention is equipped with a switch device that opens/closes the connection between the load and the electric wire; device disconnects the switching device. Therefore, even if a leakage occurs occasionally in the load, since the switchgear can be cut off, electric shock can be avoided.

More specifically, in the tenth invention, the control device of the heating and cooking apparatus of the seventh invention is equipped with a power switch having a reset function for opening/closing the connection between the load and the power supply unit; When the signal of the judging unit is abnormal, the control device turns off the power switch. Thus, even if a leakage occurs occasionally in the power supply unit or the control device, the switchgear can be turned off to cut off the power supply. As a result, electric shock can be avoided.

More specifically, in the eleventh invention, the heating and cooking apparatus of the seventh invention includes: a power switch with a reset function for opening/closing the connection between the load and the power supply unit; and opening/closing the load and a switchgear for connection between electric wires; and wherein, in a case where the signal of the leakage judgment unit is abnormal, the control device disconnects the switchgear, and thereafter, when the signal of the leakage judgment unit is further abnormal, the control device disconnects switch. Thus, it can be predicted whether the leakage occurs in the load section or in both the power supply unit and the control device.

More specifically, in the twelfth invention, the heating and cooking apparatus of any one of the ninth invention to the eleventh invention is equipped with a notification device; and, when the signal of the leakage judging unit is abnormal, the notification device notifies occur. For example, since an error indicator is displayed, it is possible to notify that an electric leakage has occurred.

More specifically, in the thirteenth invention, the control device of the twelfth invention does not stop the power supply of the power supply unit while notifying the body of the leakage. As a result, the control device continues to notify without transitioning to standby mode.

The fourteenth invention is an electric appliance comprising: a load; a control device for controlling the load; a wire for supplying a power supply voltage to both the load and the control device; a current detection unit for detecting an unbalanced current flowing through the wire; A signal output by the detection unit, an electric leakage judging unit for judging whether there is an electric leakage; a main switching device for opening/closing an electric wire; and a switch connected in parallel with the main switching device; wherein, in a standby mode in which the main switching device is disconnected, the closing switch is , so as to start the supply of the power supply voltage, so that the control device starts its control operation; when the leakage judging device judges that no leakage has occurred, since the control device closes the main switching device, even if the switch is opened, the subsequent operation of the control device is continued, and Since the control device disconnects the main switching device, the power supply to the control device and the load is stopped. As a result, risky aspects of occurrence of electric leakage or electric shock can be mitigated, and power consumption in standby mode can be reduced.

More specifically, in the fifteenth invention, the control device of the fourteenth invention turns off the main switching device to stop power supply to the control device and the load in the case where the leakage judging means judges that a leakage has occurred. As a result, risky aspects of occurrence of electric leakage or electric shock can be mitigated, and power consumption in standby mode can be reduced.

More specifically, in the sixteenth invention, the control device of the fourteenth invention turns off the main switching device in a case where no state transition occurs within a predetermined time. As a result, the power supply to the control device is automatically stopped so that the automatic power-off function can be realized.

More specifically, in the seventeenth invention, even when the predetermined time has not elapsed, the control means of the sixteenth invention turns off the main switching device in the case where the electric leakage judging means judges that the electric leakage has occurred. As a result, power supply to control devices and loads is stopped, so that risky aspects of occurrence of electric leakage or electric shock can be mitigated.

More specifically, in the eighteenth invention, since the control device of the fourteenth invention or the seventeenth invention is equipped with a notification device, when the leakage judgment device judges that a leakage has occurred, the control device can make a notification and can shut off Turn on the main switchgear.

More specifically, in the nineteenth invention, since the control device of the fourteenth invention is equipped with a storage device, when the signal of the leakage judging device is abnormal, the leakage information is stored in the storage device, so that it can be retrieved from the control device Export this information.

More specifically, in the twentieth invention, since the control device of the fourteenth invention is equipped with both the storage device and the display device, in the case where the leakage judging device judges that a leakage occurs, the control device stores the leakage information in the storage device In addition, when the signal of the leakage judgment device is normal, the control device notifies the above information stored in the storage device. As a result, the user can grasp the occurrence of electric leakage that occurred in the past.

More specifically, in the twenty-first invention, the control device of the fourteenth invention is equipped with a microcomputer; the microcomputer is equipped with operating a load connected to the electric wire in a predetermined state in order to check whether the judgment made by the leakage judgment device is normal or not The inspection program, and the microcomputer executes the inspection program through predetermined operations. As a result, leakage inspection can be performed.

More specifically, in the twenty-second invention, the control device of the twenty-first invention is provided with notification means so that the result of executing the checking procedure can be notified.

Embodiments of the present invention will now be described with reference to the drawings. It should be understood that the present invention is not limited to the following examples.

(Example 1)

FIG. 1 is an external view of a microwave oven according to a first embodiment of the present invention.

As shown in FIG. 1, a power cord 2 is provided in an appliance main body 1, and receives an AC power supply voltage from a commercial power supply. When the ground terminal 3 is provided on the main body 1 , the ground wire 4 is connected to the ground terminal 3 so as to ground the appliance main body 1 . Since the outer shell of the microwave oven is covered by metal, grounding the outer shell can avoid the risk of electric shock failure, thus ensuring safety.

FIG. 2 is a circuit diagram of a microwave oven according to a first embodiment of the present invention.

As shown in FIG. 2, reference numeral 1 designates a main body of the appliance, and shows a state in which a metal portion of the case is grounded through a ground wire 4. As shown in FIG. Also, an AC power source 5 is connected to the appliance main body 1 from a commercial power source. Reference numeral 6 denotes a power supply unit in which an AC power supply 5 is used as an input power supply. In the power supply unit 6, the power supply circuit 7, the relays 8a and 8b, the noise filter circuit 9, and the electric leakage detection circuit 10 are provided in the same unit. The power circuit 7 converts the AC voltage from the AC power source 5 into a DC voltage electrically isolated from the AC power source 5 . The relays 8 a and 8 b turn on/off the supply of the AC voltage serving as the power supply voltage of the internal units of the appliance main body 1 . The noise filter circuit 9 is applied in order to suppress the penetration of noise generated from the internal unit of the appliance to the outside of the appliance, and the noise filter circuit 9 is installed if necessary. As the power supply circuit 7, in general, a switching power supply having excellent power conversion efficiency is applied in this embodiment. Alternatively, a low-voltage converter may be applied in the power supply circuit 7 . Reference numeral 11 shows a control unit. Although not shown in FIG. 2 , in the case of a microwave oven, the control unit 11 controls operations of respective units of the appliance body 1 such as a high frequency generator for electromagnetic heating operation, and a cooling fan motor.

Operations and effects related to the microwave oven provided in the above manner will now be described.

First, when the AC voltage of the AC power source 5 is applied by connecting the power cord 2 of the microwave oven to a commercial power source, the AC voltage of this AC power source 5 is brought into the power supply unit 6 in the first case. The AC voltage of the AC power source 5 is applied to one side contacts of the relays 8 a and 8 b through the noise filter circuit 9 , and is also applied to the power supply circuit 7 . When the AC voltage of the AC power supply 5 is input into the power supply circuit 7 , a DC voltage (+12V) is generated as a power supply voltage of the control unit 11 . The control unit 11 turns on the switch 12 provided in the control unit 11 in response to the operation mode of the appliance to apply a power supply voltage driving the relays 8 a and 8 b provided in the power supply unit 7 . It should be understood that the switches 12 applied in this case may be arranged by using semiconductors, or alternatively, may be arranged by using other devices. When the DC voltage (+12V) driving the relays 8a and 8b is applied, the current flowing through the coils of the relays 8a and 8b flows through the resistor 13 to the base of the transistor 14, so the transistor 14 is turned on, thereby continuing to turn on the relays Contacts for 8a and 8b. As previously described, due to the function of the control unit 11 , when necessary, AC power is supplied to the control unit 11 in order to control the supply of AC power as a power supply voltage for driving the respective units equipped in the appliance main body 1 .

By applying these arrangements, the supply of AC power to the respective units equipped in the appliance body 1 is stopped, so that the AC power source 5 can be cut off from the appliance body 1 except for the power supply unit 6 due to the disconnection of the relays 8a and 8b. Furthermore, since the DC voltage (+12V) applied to the control unit 11 is also isolated by the inverter 15 constituting the power supply circuit 7, the control unit 11 is similarly electrically isolated from the AC power supply 5, resulting in a safer structure. In addition, since the circuit portion continuously applying the AC power supply voltage of the AC power supply 5 is concentrated in the power supply unit 6, such a circuit portion having a high risk of electric leakage can be concentrated, so that a solution capable of preventing electric leakage can be easily taken in terms of structure.

Next, the operation of the leakage sensing circuit 10 is described. Reference numeral 16 is a zero-phase converter. Zero-phase current transformer 16 senses the difference between the input AC current and the output AC current, and generates a voltage in response to the difference. Reference numeral 17 shows a judging circuit. In a case where the output voltage from the zero-phase current transformer 16 exceeds a predetermined threshold, the judgment circuit 17 judges that a leakage has occurred, and outputs a judgment result. In the case of the present embodiment, when the judging circuit 17 judges that a leakage has occurred, the judging circuit 17 outputs a signal having a level of "0V" to the base of the transistor 14 to cut off the transistor 14, so that the judging circuit 17 cuts off the relay 8a and 8b.

Thus, when a leakage occurs in the appliance main body 1, the leakage sensing circuit 10 cuts off the relays 8a and 8b to stop AC power supply to internal units of the appliance main body 1, so that malfunctions caused by the leakage can be avoided in advance.

Furthermore, in the present embodiment, when the relays 8a and 8b are turned off, the supply of AC power to the respective units of the appliance main body 1 is stopped. As a result, in the standby mode in which the microwave oven is not used, since the relays 8a and 8b are cut off, the power consumed in the relays 8a and 8b can be reduced while the failure caused by leakage current can be prevented, and therefore, the power consumption of the relays 8a and 8b can be realized. consumption of a safer circuit arrangement.

Also, while relays 8a and 8b are turned off, since there is no need to sense leakage, the supply of power supply voltage to leakage sensing circuit 10 can be stopped, unnecessary power consumption can be suppressed, and the function can be further reduced. In this embodiment, the appliance main body 1 is arranged in such a manner that by operating the switch 12 of the control circuit 11, the supply of DC voltage (+12V) to the relays 8a and 8b, and the leakage sensing circuit 10 is simultaneously started/stopped, that is, , illustrating how this makes the drive circuit simple. Alternatively, the supply of DC voltage (+12V) may be controlled separately.

(Example 2)

Fig. 3 is an external view of a heating cooking device according to a second embodiment of the present invention. As shown in FIG. 3 , a door 1002 is provided on the front of the main body 1001 in such a manner that it can be freely opened/closed. Reference numeral 1003 denotes an operation panel. A display element 1004 and a keyboard 1005 are provided on an operation panel 1003 . The ground wire 1007 is connected to the ground terminal 1006 provided on the main body 1001 so as to ground the main body 1001 . Reference numeral 1008 denotes a power cord.

Fig. 4 represents a circuit diagram of a heating cooking device according to a second embodiment of the present invention. As shown in FIG. 4, numerals 1010a and 1010b respectively show a high-frequency generator and a heater (corresponding to a heat source), that is, the load of the present invention. The high-frequency generator 1010a is arranged through a magnetron or the like, and generates microwaves to heat food corresponding to the material to be heated. The power supply voltage for these loads is applied from the power line 1008, through the line 1008a of the commercial power supply, via the relays 1011a, 1011b, 1011c, and 1011d, which function as switches controlled by the control means of the present invention. Furthermore, for all these loads, their two terminals are cut off with respect to the power supply by relays 1011a and 1011b. Relays 1011a, 1011b, 1011c, and 1011d are designed to be actuated by turning on transistors 1012a, 1012b, 1012c, and 1012d so that current can flow through the coils of these relays 1011a, 1011b, 1011c, and 1011d. These transistors 1012a, 1012b, 1012c, and 1012d operate in response to control signals supplied from the microcomputer 1013 constituting the control means.

Reference numeral 1014 shows an AC/DC converter constituting a power supply unit for generating a DC voltage (+5V) required to operate the control device. The AC/DC converter 1014 is directly connected to a commercial power line 1008 a supplied from a power line 1008 . This type of power supply has a function that suppresses power consumption to 10mV or less when no load is connected. The above-mentioned AC/DC converter can reduce unnecessary power consumption during the standby mode, so that the standby power of the heating and cooking device can be reduced when the power saving feature of the AC/DC converter 1014 itself in the standby mode can be effectively utilized. A zero-phase current transformer 1015 corresponding to the current detection unit of Embodiment 2 of the present invention is provided on the electric wire 1008a connected to the power supply wire 1008 so that the zero-phase current transformer 1015 detects an unbalanced current generated in the electric wire 1008a. The unbalanced current is caused by the current supplied from the wire behind the zero-phase converter 1015 from the case of the main body 1001 due to insulation aging, or a ground fault related to the wire and the load and control devices connected to the wire. and the ground connection to the case leaks out.

Reference numeral 1016 shows a leakage judgment unit that converts the output of the zero-phase current transformer 1015 into a signal level that can be judged by the microcomputer 1013 . For example, when the unbalanced current exceeds 10 mA (milliamperes), the leakage judgment unit 1016 outputs an output voltage having a “Vdd” level corresponding to the power supply voltage of the microcomputer 1013 . When the unbalanced current is lower than or equal to 10 mA, the leakage judgment unit 1016 outputs an output voltage equal to 0V, that is, the reference potential of the microcomputer 1013 . Based on the output signal of the electric leakage judging unit 1016, the microcomputer 1013 judges whether or not electric leakage occurs. Furthermore, the value of this unbalanced current is set to a value that does not adversely affect the human body by considering the condition of the operating time, for example, until the contacts of the relays 1011a and 1011b are opened after leakage is detected.

Reference numeral 1017 denotes a power supply unit of the present invention. Since the transistor 1018 constituting the power supply unit 1017 is turned on/off, power supply to the control device and other devices can be controlled. In the second embodiment of the present invention, the microcomputer 1013 , leakage judgment unit 1016 , display element 1004 , and keyboard 1005 constituting the control means operate to receive power supply from the power supply unit 1017 of the power source.

Reference numeral 1019 denotes an initial signal generation unit. The door switch 1020 is equipped with an initial signal generation unit 1019 , and is turned on/off in cooperation with the opening/closing operation of the door 1002 provided on the front of the main body 1001 . The initial signal generation unit 1019 is designed to generate an initial signal in response to the on/off operation of the door switch 1020 . In response to an initial signal output from the initial signal generation unit 1019, or a power hold signal output from the microcomputer 1013, the power supply unit 1017 is turned on, or its on state is maintained. In the state where the transistor 1018 of the power supply unit 1017 is cut off, the power supply to the control device etc. is stopped, and the microcomputer 1013 which controls the whole system of the heating cooking apparatus is in a suspension state. Furthermore, since the transistors 1012a, 1012b, 1012c, and 1012d respectively coupled to the coils of the relays 1011a, 1011b, 1011c, and 1011d are disconnected, the relays 1011a, 1011b, 1011c, and 1011d don't consume power. Furthermore, since the door switch 1020 is turned off when the door 1002 is closed, the initial signal generating unit 1019 does not consume power. As described above, the output current of the AC/DC converter 1014 becomes extremely small, and the power consumption of the heating and cooking apparatus also becomes extremely small.

Operations and effects related to the heating and cooking apparatus provided in the above manner will now be described as follows.

First, the operation of the initial signal generating unit 1019 will be explained. FIG. 5 is a timing chart representing voltages of respective units of the initial signal generation unit 1019 when the gate 1002 is turned off and closed. FIG. 5( a ) shows a timing diagram when the door 1002 is closed and the door switch 1020 is off; and FIG. 5( b ) shows a timing diagram when the door 1002 is closed and the door switch 1020 is on. FIG. 5(a) shows the duration from the state in which the door 1002 is closed in the standby mode, and the door 1002 is opened, the microcomputer 1013 is operated, and then the operating state is continued. The relationship between the door 1002 and the door switch 1020 is given as follows: when the door 1002 is closed, the door switch 1020 is off, and when the door 1002 is opened, the door switch 1020 is on. When the user opens the gate 1022 in standby mode, the gate switch 1020 is turned on to generate a voltage of +5V across V1 and V2. When a voltage is generated on V2, a charging current flows through the capacitor 1021, and then, a voltage of V3 as shown in FIG. 5(a) is generated on V3 until the charging current becomes zero. The transistor 1022 is turned on by the voltage generated on V3, and V4 becomes 0V level, and thus, the base current of the transistor 1018 flows to turn on the transistor 1018. Due to the initial signal generating unit 1019, the power supply unit 1017 is turned on so that the microcomputer 1031 starts operating. Then, the microcomputer 1013 outputs a power supply hold signal (V5) to turn on the transistor 1023 of the power supply unit 1017, continues to supply a voltage of +5V to Vdd, and thus continues to operate.

The ON/OFF logic operations of the door switch 1020 shown in FIG. 5(b) are opposite to those of FIG. 5(a). That is, the relationship between door 1002 and door switch 1020 is given as follows: when door 1002 is closed, door switch 1020 is on, and when door 1002 is open, door switch 1020 is off. When the user opens the door 1022 in standby mode, the door switch 1020 is opened to change the voltage of +5V to 0V. The voltage on V2 corresponds to the state that the charge stored in the capacitor 1021 is discharged through the resistor 1021, gradually changes from +5V to 0V, and then remains at 0V until the gate 1002 is closed again.

Next, when the gate 1002 is closed and thus the gate switch 1020 is turned on, the voltage of V2 becomes +5V. If a voltage is generated on V2, a charging current flows through the capacitor 1021, and the voltage of FIG. 5(b) is generated until the charging current becomes zero. In response to the voltage generated across V3, transistor 1022 is turned on, the voltage of V4 becomes 0V level, and thus, the base current of transistor 1018 flows, thereby turning on transistor 1018. Due to the operation of the initial signal generating unit 1019, the power supply unit 1017 is turned on so that the microcomputer 1031 starts operating. Then, the microcomputer 1013 outputs a power supply hold signal (V5) to turn on the transistor 1023 of the power supply unit 1017, continues to supply a voltage of +5V to Vdd, and thus continues to operate.

Next, if the power source power supply unit 1017 starts to apply +5V to Vdd, the electric leakage judging unit 1016 is operated. The zero-phase current transformer 1015 can detect the unbalanced current generated in the wire 1008a, and generate an output voltage proportional to this unbalanced current. While the leakage judging unit 1016 monitors the output voltage generated by the zero-phase current transformer 1015, if the monitored output voltage becomes higher than or equal to the sensing voltage, the leakage judging unit 1016 judges that a leakage has occurred, and outputs information about the microcomputer 1013's judgment result. In a normal state where no leakage occurs, the microcomputer 1013 turns on and off the relays 1011a, 1011b, 1011c, and 1011d in a pre-programmed order to control the high-frequency generator and heat source to heat the material to be cooked. Then, after the cooking is completed, under the condition that the state does not transition within a predetermined time (for example, under the condition that the keyboard 1005 is not manipulated), the microcomputer 1013 lowers the level of the power supply maintenance signal to 0V level to stop the operation. The power supply unit 1017, the microcomputer 1013 stop the power supply to both the control device and the electric leakage judging unit 1016, and transition to the standby mode.

Next, the operation in the case where the occurrence of electric leakage is detected is described. When the relays 1011a, 1011b, 1011c, and 1011d are turned on and off to apply voltage to the high frequency generator and the load corresponding to the heat source, the microcomputer 1013 immediately turns off the relays to stop the voltage supply. And, the microcomputer 1013 makes the display element 1004 notify the user of the occurrence of such electric leakage, so as to prompt to suspend the use of the cooking device. Furthermore, while the display element 1004 is notifying the occurrence of electric leakage, the microcomputer 1013 does not transition to the standby mode, but continues to issue the notification.

(Example 3)

FIG. 6 is a circuit diagram of a microwave oven according to a third embodiment of the present invention. It should be understood that the same reference numerals shown in Embodiment 2 are used as those designating the same structural elements of Embodiment 3, and their descriptions are omitted. As a difference from the second embodiment, a power switch 1025 having a reset function is provided in front of the wires connected to the load and the power supply unit. The power switch 1025 is arranged in such a way that when the power switch 1025 is manually switched to the closed state, the closed state is maintained by the magnetron. Although it is also possible to manually switch the power switch 1025 to the OFF state, this power switch 1025 can return to the OFF state if power is applied to the coil 1025a, and then, a repulsive force is generated in a direction to open its contacts.

Operations and effects related to the microwave oven provided in the above manner will now be described.

First, since the power switch 1025 enters a closed state, power is supplied to the AC/DC converter 1014 to output a voltage of +5V therefrom. In such a state, the heating and cooking device is still in the standby mode, and the power consumption of the AC/DC converter 1014 becomes equal to the heating and cooking device consumption in a state where the output current of the AC/DC converter 1014 is an extremely small current. electricity. In recent years, there are some AC/DC converters in which the standby power is less than or equal to 10 mW when there is no output current; and since the output of the AC/DC converter is reduced as low as possible, the power consumption of the cooking device in the standby mode can be reduced to less than or equal to 50mW.

Next, since the gate 1002 is opened and closed, a voltage of +5V is applied to the microcomputer 1013, so that the microcomputer 1013 proceeds to the operation mode. In this normal state where no leakage occurs, the microcomputer 1013 turns on and off the relays 1011a, 1011b, 1011c, and 1011d according to the sequence programmed in advance, so as to control the high-frequency generator 1010a and the heater 1010b, thereby heating the food to be cooked. s material. Then, after the cooking is completed, under the condition that the state does not transition within a predetermined time, since the microcomputer 1013 lowers the level of the power supply holding signal to 0V level so as to stop the power supply unit 1017, the microcomputer 1013 stops controlling the control device. and the electric power supply of the electric leakage judging unit 1016, and transition to the standby mode.

Next, the operation in the case where the occurrence of electric leakage is detected is described. In the case of turning on and off the relays 1011a, 1011b, 1011c, and 1011d, respectively, so as to apply voltage to the high frequency generator 1010a and the load corresponding to the heat source 1010b, the microcomputer 1013 immediately turns off the relays so as to stop the voltage supply . Since the relay is cut off, if the output of the electric leakage judging unit 1016 returns to a normal state, the microcomputer 1013 makes the display element 1004 notify the user of the occurrence of this electric leakage, so as to prompt to suspend the use of the cooking device. In addition, while the display element 1004 is notifying the occurrence of the leakage, the microcomputer 1013 does not enter the standby mode, but continues to issue the notification. When both ends of the load are cut off, when the leakage judging unit 1016 further judges that the leakage occurs, the microcomputer 1013 immediately outputs a signal to turn on the transistor 1026, and supplies power to the coil 1025a to disconnect the contact of the power switch 1025.

(Example 4)

Fig. 7 shows an external view of a microwave oven according to a fourth embodiment of the present invention. As shown in FIG. 7, a door 2002 is provided on the front of the main body 2001 in a freely openable/closeable manner. Reference numeral 2003 denotes an operation panel. On the operation panel 2003, a display unit 2004, a keyboard 2005, and a power ON key 2006 are provided. The ground wire 2008 is connected to the ground terminal 2007 provided on the main body 2001 so as to ground the main body 2001 . Reference numeral 2009 denotes a power cord.

Fig. 8 represents a circuit diagram of a microwave oven according to a fourth embodiment of the present invention.

As shown in FIG. 8 , a power source is connected to a contact of a relay 2010 , and is connected to a high-frequency generator 2012 through a contact of another relay 2011 from a power supply line 2009 . Relay 2010 corresponds to the main switching device of the present invention. The high frequency generator 2012 is arranged by a magnetron etc., and the magnetron generates microwaves in order to heat food corresponding to the material to be heated. As a load of the present invention, a high-frequency generator 2012 is described in the fourth embodiment of the present invention. Reference numeral 2013 denotes a control device, and electric power is supplied to the control device 2013 through a low-voltage converter 2014 . In the control device 2013, a microcomputer 2015, a keyboard 2005, a display unit 2004 functioning as a notification device, and a storage device 2016 are provided. The microcomputer 2015 controls processing operations of signals from the keyboard 2005 input from the outside, display processing operations of the display unit 2004 , and operations of the relays 2010 and 2011 . Reference numeral 2017 shows a case that is grounded through the ground wire 2008 of the main body 2001 . A zero-phase current transformer 2018 corresponding to a current detector is provided in the electric wire 2009a originating from the power supply line 2009, so that the zero-phase current transformer 2018 detects generation of an unbalanced current in the electric wire 2009a. The unbalanced current is caused by the following reasons: that is, the current supplied by the wire 2009a behind the zero-phase current transformer 2018 is due to insulation aging, or is related to the wire 2009a, and the high-frequency generator 2012 connected to the wire 2009a (that is, the load ) and the ground fault related to the control device 2013 leaks from the shell 2017 of the main body 2001 and the ground connected to the shell 2017. Reference numeral 2019 shows a leakage judgment device that converts the output of the zero-phase current transformer 2018 into a signal level that can be judged by the microcomputer 2015 . For example, in the case where the unbalanced current exceeds 10 mA, the leakage judgment device 2019 outputs an output voltage having a “Vdd” level corresponding to the power supply voltage of the microcomputer 2015 . When the unbalanced current is lower than or equal to 10 mA, the leakage judgment device 2019 outputs an output voltage having a "Vss" level of the reference potential of the microcomputer 2015 . According to the output signal of the electric leakage judging device 2019, the microcomputer 2015 judges whether electric leakage occurs. In addition, the value of this unbalanced current is set to a value that does not adversely affect the human body in consideration of conditions such as the operating time until the contact of the relay 2010 is opened after leakage is detected. Reference numeral 2020 denotes a switch connected in parallel with the contacts of the relay 2010 . The switch 2020 is designed to be closed by pressing the power on key 2006 provided on the main body 2001 .

Operations and effects related to a microwave oven to which the above arrangement is applied will now be described.

First, in a state where the contacts of the relay 2010 are open, power is not supplied to both the control device 2013 and the high-frequency generator 2012, causing the microwave oven to enter a standby mode. When the user uses the microwave oven, first, the user presses the power ON key 2006 . As a result, the switch 2020 is closed, and power is supplied from the low-voltage converter 2014 to the control device 2013, and the control device 2013 starts to operate. In a case where no electric leakage occurs in response to an output signal from the electric leakage judging device 2019 , the microcomputer 2015 provided in the device 2013 closes the contacts of the relay 2010 . Since the contacts of the relay 2010 are closed, power is then supplied to the control device 2013 and causes it to continue operating.

Next, when the user inputs both the cooking mode and the heating time by manipulating the keyboard 2005, and inputs a start command through the keyboard 2005, the relay driving unit 2021b closes the contacts of the relay 2011 in response to an output from the microcomputer 2015. Thus, power is supplied to the high frequency generator 2012 to generate microwaves, thereby heating food. When the cooking is finished, the microcomputer 2015 turns off the contacts of the relay 2011. In the case where all the cooking is thus completed, and then the microwave oven shifts to the standby mode, the user inputs a power-off command by manipulating the keypad 2005 so as to open the contacts of the relay 2010. As a result, the microwave oven transitions into standby mode.

Alternatively, in order to avoid such a troublesome input operation of the power-off command, or in a case where the user forgets to input the power-off command after using the microwave oven, for example, when providing a At the same time as the waiting time for inconvenience, the microwave oven can be equipped with an automatic power-off function, that is, when the user does not perform any operation within this waiting time, the microcomputer 2015 can disconnect the contact of the relay 2010 to make the microwave oven switch to Alternate mode.

Furthermore, in the case where the electric leakage judging device 2019 judges that electric leakage has occurred when the contacts of the relay 2010 are closed, the microcomputer 2015 immediately cuts off the contacts of the relay 2010 to improve safety.

Also, in the fourth embodiment, in the case of failure of the microcomputer 2015, the microwave oven is provided in such a manner that the relay drive unit 2021a receives the output signal of the electric leakage judging device 2019. When the output signal of the leakage judging device 2019 constitutes a signal having a "Vdd" level, the relay drive unit 2021a can open the contact of the relay 2010 in response to the output signal of the leakage judging device 2019 regardless of the output signal from the microcomputer 2015. point.

In addition, under the situation that the electric leakage judging device 2019 judges that electric leakage has occurred, the microcomputer 2015 displays an error indication on the display unit 2004, and, when the contact of the relay 2010 is closed, the microcomputer 2015 disconnects the contact of the relay 2010 to The electric wire 2009a is cut off, and the power supply to the part where the electric leakage occurs is stopped. Even if the contact of the relay 2010 is opened, the control device 2013 can indicate an error on the display unit 2004 due to a backup structure such as a smoothing capacitor provided on the secondary side of the low-voltage converter 2014 that supplies power to the control device 2013. continue to display for a while. As a result, the microcomputer 2015 can notify the user of the occurrence of electric leakage. The time period during which this false indication continues to be displayed can easily be extended by increasing the capacitance of the smoothing capacitor described above. Furthermore, in order to further prolong the time period in which an error is displayed, an additional electric leakage display unit and a backup power supply only for the electric leakage display unit may alternatively be provided. When the driving voltage of the control device 2013 becomes lower than the power supply voltage capable of driving the control device 2013, the control device 2013 stops transitioning to the standby mode.

In addition, when the leakage judgment device 2019 judges that a leakage has occurred, the microcomputer 2015 displays an error indication on the display unit 2004, and stores the error information into the memory device 2016 equipped in the control device 2013; in addition, when the relay 2010 When the contacts of the relay 2010 are closed, the microcomputer 2015 opens the contacts of the relay 2010 and cuts the electric wire 2009a, thereby stopping the power supply to the place where the leakage occurs.

In addition, the microcomputer 2015 displays an error indication and stores error information in the storage device 2016 as follows: that is, when the contact of the relay 2010 is closed, the microcomputer 2015 first opens the contact of the relay 2010, and then With a backup structure such as a smoothing capacitor on the secondary side of the low-voltage converter 2014 that supplies power to the control device 2013, the control device 2013 continues to operate while displaying and storing information as described above. As a result, the microcomputer 2015 can cut off the electric wire 2009a more quickly so as to stop the power supply to the place where the leakage occurs.

Also, since cooking equipment such as a microwave oven may generate a lot of steam depending on the food during cooking, it creates temporary dew drops, and electric leakage may occur in some places. When a leakage occurs occasionally, the microcomputer 2015 opens the contact of the relay 2010 according to the output signal of the leakage judging device 2019, so that the control device 2013 stops operating to transition to the standby mode. Dew drops can cause temporary leakage, which may disappear after a while. Users who are not in the vicinity of the microwave oven may ignore the occurrence of such leakage. In such a case, when the user manipulates the power on key 2006 again to operate the microwave oven, the electric leakage judging device 2019 does not detect the occurrence of electric leakage, but can operate in a normal state. In some cases, the above phenomenon can be managed as a non-reproducible failure claim. In order to accept such an irreproducible failure assertion, the contents of the error are stored in the storage device 2016 provided in the control device 2013 in advance. The user or the service personnel use the keyboard 2005 to input an error call command, so that the wrong content can be called.

As previously described, in the fourth embodiment, when the microwave oven is in the standby mode, the main switching device such as a relay cuts off the wires to the load and the control device, which reduces the risk caused by electric leakage or electric shock. In addition, standby power can be reduced since there is no unnecessary power consumption.

In the fourth embodiment, the power on key 2006 is applied; and, when the power on key 2006 is pressed and the switch 2020 is closed to supply power to the control device 2013, the microwave oven starts to operate. Alternatively, it can be designed such that when the door 2002 is opened, the switch 2020 can be closed. As a result, the power-on key 2006 is no longer necessary, and therefore, the troublesome operation for the user to press the power-on key 2006 every time cooking can be omitted.

(Example 5)

Fig. 9 is a circuit diagram of a microwave oven according to a fifth embodiment of the present invention. It should be understood that the same reference numerals shown in Embodiment 4 are used as those denoting the same structural elements of Embodiment 5, and their descriptions are omitted. As a difference from the fourth embodiment, in the fifth embodiment, a heater 2022 is applied in addition to the high-frequency generator 2012 in the case where a plurality of loads of the present invention are installed. As a result, a hotplate function and a grill function are additionally provided. Both high frequency generator 2012 and heater 2022 can be operated or powered by opening/closing relay 2011 , relay 2023 , and relay 2024 . These relays 2011 , 2023 , and 2024 are driven by the relay driving unit 2021 c upon receiving a control signal from the microcomputer 2015 .

Next, when the food is heated with microwaves at high frequency, the relay 2011 is closed to supply power to the high frequency generator 2012 to generate microwaves therefrom and irradiate the food. When the heater 2022 heats food, both the relays 2023 and 2024 are closed to supply power to the heater 2022, causing the heater 2022 to generate heat, thereby heating the food.

In such an arrangement, for example, when the insulation of heater 2022 and the insulation of housing 2017 are degraded, no power is supplied to heater 2022 unless both relays 2023 and 2024 are closed. As a result, electric leakage cannot be detected. In such a case, when the program for inspection is stored in the microcomputer 2015 in advance, since the user inputs an instruction to execute the program for inspection with the keyboard 2005, all loads can be automatically switched on and off for operation. As a result, the microcomputer 2015 can check whether or not electric leakage has occurred in the heater 2022 and the high frequency generator 2012 . In the fifth embodiment, description will be made in the case where the heater 2022 and the high-frequency generator 2012 are used as two loads. The above leakage check may become more effective when more than two loads are used in the appliance. Furthermore, when a leakage is detected during the inspection, since the display unit 2004 displays an error indication notifying that the load is operating and that a leakage has occurred, this error indication can lead to effective information that can specify where the leakage occurred.

(Example 6)

Fig. 10 is a circuit diagram of a microwave oven in which a main switchgear is provided in a wire to a control device. It should be noted that the same reference numerals shown in the fourth embodiment are used as those denoting the same structural elements in the sixth embodiment. The structural points different from the 4th embodiment are given as follows: That is, when the relay 2025 corresponding to the main switching device of the present invention is equipped on the electric wire 2009a to the control device 2013, the high-frequency generator corresponding to the load 2012 is connected to the wire 2009a via another relay 2026 and another relay 2011.

Operations and effects related to a microwave oven to which the above arrangement is applied will now be described.

First, in a state where the contacts of the relay 2025 are open, power is not supplied to both the control device 2013 and the high frequency generator 2012, so that the microwave oven enters the standby mode. When the user uses the microwave oven, first, the user presses the power on key 2006 to close the switch 2020 . The low voltage converter 2014 then starts supplying power to the control device 2013 for operation. When the microcomputer 2015 equipped in the control device 2013 judges that no electric leakage occurs according to the output signal of the electric leakage judging device 2019 , the microcomputer 2015 closes the contact of the relay 2025 . Due to the closure of the contacts of the relay 2025, power is then supplied to the control device 2013 in order for it to continue to operate.

Next, the user inputs both the cooking mode and the heating time with the keyboard 2005, and inputs a start command with the keyboard 2005, so that the relay driving unit 2021d closes the contacts of the relay 2011 and the contacts of the relay 2026 in response to the output from the microcomputer 2015. Thus, power is supplied to the high frequency generator 2012 to generate microwaves to heat food. When the cooking is finished, the microcomputer 2015 disconnects the contact of the relay 2011 and the contact of the relay 2026. When all cooking is done and the microwave oven then transitions into standby mode, the user enters a power off command with keypad 2005 to open the contacts of relay 2025, which causes the microwave oven to enter standby mode.

Alternatively, in order to avoid such a troublesome input operation of the power-off command, or in the case where the user forgets to input the power-off command after using the microwave oven, for example, providing While the waiting time of the inconvenience is felt, the microwave oven can be provided with an automatic power cut function, that is, when the user does not perform any operation within this waiting time, the microcomputer 2015 can disconnect the contact of the relay 2025, so that the microwave oven enters the standby mode. model.

Furthermore, in the case where the electric leakage judging device 2019 judges that electric leakage has occurred when the contact of the relay 2025 is closed, the microcomputer 2015 immediately cuts off the contact of the relay 2025 to improve safety.

In addition, in the case where the leakage judging device 2019 judges that a leakage has occurred during the high-frequency heating operation, the microcomputer 2015 turns off the relays 2011 and 2026 to stop the power supply to the high-frequency generator 2012, and also causes the display unit 2004 to display an error instruct. Furthermore, even when the power supply operation to the high-frequency generator 2012 is stopped, when the leakage judging device 2019 judges that a leakage has occurred, the microcomputer 2015 turns off the relay 2025 to stop the microwave oven.

As previously described, in the sixth embodiment, when the microwave oven is in the standby mode, the main switching device cuts off the wire to the control device, and another switching device such as a relay cuts off the load from the wire. As a result, risks caused by electric leakage or electric shock can be reduced, and since there is no unnecessary power consumption, standby power can be reduced.

Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications and changes can be made without departing from the technical scope and spirit of the present invention. This patent application requires Japanese patent application JP2006-101760 filed on April 3, 2006, Japanese patent application JP 2005-338210 filed on November 24, 2005, and Japanese patent application JP 2005-2005 filed on August 26, 2005 245618, which is hereby incorporated by reference in its entirety.

Industrial applicability

As described above, in the electric appliance according to the present invention, the power consumption of the leakage detection circuit in standby mode can be eliminated without impairing the effect of the leakage interruption function capable of preventing leakage or electric shock. As a result, the electric appliance can also be applied to a field of use for reducing power consumption of home appliances equipped with an earth leakage interruption function. Furthermore, in the heating cooking apparatus according to the present invention, the power consumption of the electric leakage detection circuit in standby mode can be eliminated without impairing the effect of the electric leakage interrupt function capable of preventing electric leakage or electric shock. As a result, the heating and cooking apparatus can also be applied to the field of use for reducing power consumption of home appliances equipped with leakage interruption functions, and when home appliances are reequipped with leakage interruption functions that replace leakage solutions provided in conventional appliances, Its functionality in standby mode must be reduced to another field of use that is as small as possible.

Claims (3)

1. electrical equipment comprises:

Use the appliance body of AC power supplies; With

Be provided in the power subsystem in the described main body, it is connected to the described AC power supplies of input so that dc voltage and AC Voltage-output are arrived described appliance body;

Wherein, described power subsystem comprises:

Be used for the voltage transitions of described AC power supplies is become the power circuit of the dc voltage of isolating with described AC power supplies electricity;

Be used for connecting and cutting off the relay that the AC voltage of appliance body is supplied; With

Be provided in the contact of described relay and the leakage inductance slowdown monitoring circuit between the described appliance body, for detection of the electric leakage that in described appliance body, occurs, in order to cut off described relay,

Wherein, described appliance body comprises the control unit for control apparatus, described control unit uses the dc voltage that applies from power subsystem to operate, and control is to the dc voltage supply of relay and leakage inductance slowdown monitoring circuit, wherein when electrical equipment was in standby mode, described control unit interrupt delivery was given the dc voltage of described relay and leakage inductance slowdown monitoring circuit.

2. electrical equipment according to claim 1, wherein, when described electrical equipment during at standby mode, this appliance body cuts off described relay.

3. electrical equipment according to claim 1, wherein, described power subsystem comprises noise filter circuit at the input side of AC power supplies, and described power subsystem provides as individual unit.

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