JP2001349358A - Rectifying circuit for electromagnetic brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rectifying circuit to reduce a supply power, available after the armature of the electromagnetic brake is attracted, to a value lower than a supply power during attraction when its coil winding is energized by using an AC source and the electromagnetic brake is energized. SOLUTION: This rectifying circuit 3 is to supply a direct current to energize a non-excitation operation type electromagnetic brake 1 from an AC source 2 and the rectifying circuit 3 consists of a single or a plurality of diodes D1, D2, and D3 and a single thyristor TH1. The electromagnetic brake 1 is energized by a full-wave rectified direct current by the diodes D1, D2, and D3 and the thyristor TH1. After closing of the AC source 2, the thyristor TH1 is brought into a non-energized state by a timer circuit 6 after the lapse of some time and the electromagnetic brake 1 is energized by a half-wave rectified direct current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier circuit for an electromagnetic brake, and more particularly to a rectifier circuit for supplying a direct current by using an alternating current power supply for energizing a non-excited operation type electromagnetic brake.

[0002]

2. Description of the Related Art Conventionally, as such a non-excited operation type electromagnetic brake rectifier circuit, for example, there is one connected to a motor as shown in FIG. First, FIG. 3 shows the structure of the non-excited operation type electromagnetic brake in which the upper half is formed in a cross section. In FIG. 3, the non-excited operation type electromagnetic brake 20 assembled on a rotating shaft end 31 side of a motor, for example, an induction motor 30, has a brake hub 21 as a brake movable portion fixed to the motor rotating shaft 31 and a coil winding. When the wire 22 is not energized, the brake lining 24 attached to the armature 23 is pressed against the brake hub 21 by the urging force of the coil spring 25 to apply a braking force.

When the coil winding 22 is energized, the armature 23 is attracted to the electromagnetic brake main body 26 by electromagnetic force against the urging force of the spring 25, and
1 and release the rotating shaft of the motor 30,
The brake comes off. By energizing the coil winding 22,
When the armature 23 is attracted to the electromagnetic brake main body 26 side, the resistance of the magnetic circuit is reduced. Therefore, the electric power required to attract the armature 23 is required to maintain the state after the attraction. Power is small.

[0004]

Since the AC induction motor 30 operates on an AC power supply, it is more convenient or necessary to operate the electromagnetic brake 20 incorporated in the motor 30 on the same AC power supply. A rectifier circuit 27 is required. For this reason, a motor in which the electromagnetic brake 20 and the rectifying circuit 27 are incorporated in the motor 30 is also used. The conventional electromagnetic brake 20 is often supplied with half-wave rectified DC when energized in order to suppress the heat generation of the coil winding 22 and reduce the size.

FIG. 4 shows an example of a connection diagram of a motor, an electromagnetic brake, and a rectifier circuit. In FIG. 4, reference numeral 30 denotes a single-phase AC induction motor connected to an AC power supply 32 via a switch 33; When the brake of the electromagnetic brake 20 is released by a rectifier circuit connected to the AC power supply 32 via a switch 28, a half-wave rectified DC is supplied to the coil winding 22 thereof.

However, in order to energize the electromagnetic brake 20, the rectifier circuit 27 for supplying a direct current using an AC power supply 32 has a combination of a half-wave rectifier diode 27a and a return diode 27b. Had become something. However, normally, in the case of an electromagnetic brake with a DC power input, the drive is performed by using two different voltages. Thus, there is a problem that the power required after suctioning the armature 23 of the electromagnetic brake 20 is smaller than the power required at the time of suction, that is, the characteristics of the electromagnetic brake are not sufficiently utilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to solve the above-mentioned problems, and to use an AC power supply and energize its coil winding to energize an electromagnetic brake. An object of the present invention is to provide a rectifier circuit for an electromagnetic brake in which the supply power after suction of the armature of the electromagnetic brake is smaller than the supply power during suction.

Another object of the present invention is to use an AC power supply,
An object of the present invention is to provide a rectifier circuit for an electromagnetic brake that outputs two DC voltages that can be selectively used for operation when the coil winding is energized to energize the electromagnetic brake.

[0009]

According to the present invention, there is provided a rectifier circuit for supplying a direct current for energizing a non-excited operation type electromagnetic brake from an alternating current power supply. is there.

The rectifier circuit includes a single or a plurality of diodes and a single thyristor. Immediately after the AC power is turned on, the electromagnetic brake is activated by a direct current that is full-wave rectified by the diode and the thyristor. A rectifier circuit which is energized and turns off the thyristor after a set time elapses after the AC power is turned on, and the electromagnetic brake is energized by half-wave rectified DC. .

The timer circuit comprises a capacitor, a resistor, and a transistor, and after a lapse of the set time, a gate of the thyristor becomes lower than a non-trigger voltage by an output signal from the transistor.

The timer circuit includes a capacitor, a resistor, a transistor, and a photocoupler. After an elapse of the set time, an output signal from the photocoupler operated by the transistor causes the gate of the thyristor to: This is a circuit that becomes lower than the non-trigger voltage.

According to the configuration of the present invention, when an AC power supply is used to energize and excite the coil winding of the non-excited operation type electromagnetic brake to energize the electromagnetic brake (release the brake), a rectifier circuit is provided. Flows a full-wave rectified DC for the time (short time) to suck the armature of the electromagnetic brake,
Thereafter, the above-mentioned problem is solved by outputting voltages having two different voltage values so as to flow a half-wave rectified DC. For this reason, the supply power after suctioning the armature of the electromagnetic brake can be made smaller than the supply power at the time of suction.

The service life of the electromagnetic brake is determined by the fact that the brake lining wears out and the gap between the armature and the electromagnetic brake main body side is widened and suction becomes impossible. Therefore, when the present invention is applied to a conventional electromagnetic brake, Since the suction force can be increased only for a short time immediately after the start of energization, the life can be extended. (Because the braking operation is performed by a coil spring, the conventional operation is the same.) Further, since the conventional rectifying circuit is half-wave rectification, the maximum time before the current starts to flow depends on the switch-on timing. Although there is a time lag of a half cycle of the frequency, the use of full-wave rectification has an advantage that this time lag is also eliminated.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a connection diagram of an electromagnetic brake and a rectifier circuit showing a first embodiment of an electromagnetic brake rectifier circuit of the present invention.

In FIG. 1, reference numeral 1 denotes a coil winding of an electromagnetic brake connected to an AC power supply 2 via a rectifier circuit 3. The rectifier circuit 3 includes a bridge full-wave rectifier circuit 5 including three diodes D1, D2, D3 and one thyristor TH1 connected to the AC power supply 2 via a switch 4.
And a timer circuit 6 mainly including a resistance capacitance C1, R1 circuit, a Zener diode D5, and a transistor TR1. In the timer circuit 6, D4 is a diode, and R2, R3, R5, and R6 are resistors.

Next, the operation of the rectifier circuit 3 of FIG. 1 will be described. [When the switch 4 is turned on] The switch 4
Is supplied and the AC power supply 2 is supplied to the rectifier circuit 3, the capacitor C1 is charged through the diode D4 and the resistor R1. When the charging voltage between the terminals of the capacitor C1 is equal to or lower than the Zener voltage of the Zener diode D5, the current flows to the gate of the thyristor TH1, and the thyristor TH1 conducts. Then, diodes D1, D2, D3 and thyristor TH1
The full-wave rectified current flows through the coil winding 1 of the electromagnetic brake by the bridge full-wave rectifier circuit 5 comprising:

[Interruption of Thyristor TH1] The capacitor C1 is charged, and its charging voltage is changed to a Zener diode.
When the voltage exceeds the Zener voltage of D5, the base current of the transistor TR1 is supplied through the Zener diode D5, and the transistor TR1 is turned on. When the transistor TR1 becomes conductive and the gate of the thyristor TH1 becomes lower than the gate non-trigger voltage, the thyristor TH1 becomes non-conductive. Thereafter, the gate of the thyristor TH1 is kept below the gate non-trigger voltage, and the thyristor TH1 remains non-conductive. Therefore, a half-wave rectified current flows through the coil winding 1 of the electromagnetic brake.

At this time, the charging voltage of the capacitor C1 is the sum of the Zener voltage of the Zener diode D5 and the voltage of the resistor R2. Because it is half-wave rectified by diode D4,
The capacitor C1 repeats charging and discharging at the cycle of the AC power supply 2. When the voltage of the capacitor C1 becomes equal to or less than the Zener voltage of the Zener diode D5, at the next charging, the gate signal of the thyristor TH1 is supplied through the capacitor C1 before the transistor TR1 operates, and the thyristor TH1 is turned on. Triggered and conductive. Resistor R2
If the minimum voltage of the capacitor C1 is selected to be equal to or higher than the Zener voltage, the thyristor TH1 can be kept non-conductive.

[Current path when thyristor TH1 is cut off] When the thyristor TH1 does not operate, a current flows from the AC power supply 2 through the switch 4, the diode D3, the electromagnetic brake coil winding 1, and the diode D1. In the next half cycle of the AC power supply 2, the current flows back to the electromagnetic brake coil winding 1 through the diodes D1 and D2. [Opening of Switch 4] When the AC power supply 2 is cut off by the switch 4, the voltage of the capacitor C1 is discharged through a resistor R3.

[Response to Leakage Current] The switch 4 is connected to a surge absorbing circuit (not shown) or a solid state relay such as an SSR (sol
id state relay). Then, a leakage current occurs between the contacts of the switch 4, and the capacitor C1 is charged. The capacitor C1 and the resistor R1 may be selected so as to operate even with the leakage current.
If the resistor R4 is provided and the switch C4 is opened to discharge the charge of the capacitor C1, the influence of the leakage current can be eliminated.

FIG. 2 shows a connection diagram between an electromagnetic brake and a rectifier circuit according to a second embodiment of the rectifier circuit for an electromagnetic brake of the present invention. 2, the same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The rectifier circuit 13 includes a bridge full-wave rectifier circuit 5 composed of three diodes D1, D2, D3 and TH1 connected to the AC power supply 2 via a switch 4, and mainly includes a resistance capacitance C1, R1 circuit and a Zener. The timer circuit 16 includes a diode D5 and a transistor TR1.

In the present embodiment, the timer circuit 16 is provided on the electromagnetic coil winding 1 side, and when the thyristor TH1 is turned off, the timer circuit 16 is operated by a photocoupler PHC1 including a light emitting element PHCa and a light receiving element PHCb. is there. In this case, the switch 4 can be provided at a stage subsequent to the bridge full-wave rectifier circuit 5, and the electromagnetic brake coil winding 1 can be cut off without a return current. Therefore, there is an advantage that the braking operation of the electromagnetic brake itself is accelerated. With such a configuration, the electromagnetic brake can be driven even when the switch 4 is provided on the AC power supply 2 side.

Incidentally, the technique of the present invention is not limited to the technique in the above-described embodiment, but may be implemented by means of other modes having the same function. Can be changed or added.

[0025]

As is apparent from the above description, according to the rectifier circuit for an electromagnetic brake of the present invention, the rectifier circuit comprises one or a plurality of diodes and a single thyristor. Immediately after, the electromagnetic brake is energized by the full-wave rectified direct current by the diode and the thyristor. When the electromagnetic brake is energized by half-wave rectified DC, an AC power supply is used, and the coil winding is energized to energize the electromagnetic brake.
The supply power after suctioning the armature of the electromagnetic brake can be smaller than the supply power during suction.

Further, the distance for sucking the armature of the electromagnetic brake can be widened. That is, when compared with the electromagnetic brake having the same structure, the distance that can be sucked can be extended to about twice that of the conventional one, and the life can be extended. In this case, if the same suction distance is sufficient, there is an effect that the supply power during energization can be reduced as described above.

[Brief description of the drawings]

FIG. 1 is a connection diagram of an electromagnetic brake and a rectifier circuit, showing a first embodiment of an electromagnetic brake rectifier circuit of the present invention.

FIG. 2 is a connection diagram of an electromagnetic brake and a rectifier circuit according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a structure of a conventional non-excitation operation type electromagnetic brake, in which a left half thereof is sectioned.

FIG. 4 is a diagram showing a conventional electromagnetic brake rectifier circuit and a connection diagram of the rectifier circuit, a motor, and an AC power supply.

[Explanation of symbols]

 1 Coil winding (electromagnetic brake) 2 AC power supply 3,13 Rectifier circuit 4 Switch 5 Full-wave rectifier circuit 6,16 Timer circuit C1 Capacitor D1, D2, D3, D4 Diode D5 Zener diode PHC1 Photocoupler PHCa Light emitting element PHCb Light receiving element TH1 Thyristor TR1 Transistor R1, R2, R3, ‥‥ R7 Resistor

Claims (3)

[Claims] 1. A rectifier circuit for supplying a direct current for energizing a non-excited operation type electromagnetic brake from an AC power supply, wherein the rectifier circuit comprises one or more diodes and one thyristor, Immediately after the AC power supply is turned on, the electromagnetic brake is energized by full-wave rectified DC by the diode and the thyristor, and after the AC power supply is turned on, the timer circuit elapses after a certain time set by the timer circuit. A rectifier circuit for an electromagnetic brake, wherein the thyristor is turned off and the electromagnetic brake is energized by half-wave rectified DC. 2. The method according to claim 1, wherein the timer circuit includes a capacitor, a resistor, and a transistor.
The rectifier circuit for an electromagnetic brake according to claim 1, wherein a gate of the thyristor becomes lower than a non-trigger voltage by an output signal from the transistor. 3. The thyristor gate according to claim 1, wherein the timer circuit includes a capacitor, a resistor, a transistor, and a photocoupler, and after a lapse of the set time, an output signal from the photocoupler operated by the transistor. 2. The rectifier circuit for an electromagnetic brake according to claim 1, wherein the voltage is equal to or less than a non-trigger voltage.