JP2002239730A - Speed control device for motor for feeding welding wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a conventional technical problem in which stopping time of a motor for feeding a welding wire is changed corresponding to the length of a cable, in the speed control device for the motor. SOLUTION: The number of revolution of the motor M is controlled in accordance with a motor control driving signal Sc; the value of a second relay driving signal Lb is arithmetically compared with a pre-determined disconnection detecting reference value Vr; if the second relay driving signal Lb is found larger than the reference value Vr, it is discriminated as abnormality of the cable, the comparison calculation signal Cp for detecting control cable disconnection is set at a low level; when the signal Cp is at a high level, the revolution of the motor M is maintained; when the signal Cp is at a low level, the revolution of the motor M is stopped, thereby setting the second relay driving signal Lb at a high level, closing the contact point of a second reduction relay RLY2, causing resistance loss in the current of an electromotive force generating at the time of reduction of the motor M, and thereby quickly reducing speed, in this speed control device for the motor for feeding a welding wire.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to speed control of a wire feeder used in a consumable electrode type welding machine.

[0002]

2. Description of the Related Art FIG. 2 is a connection diagram of a speed control device of a wire feed / feed motor of a conventional consumable electrode type welding machine, and FIG. 3 is a diagram for explaining the operation of the speed control device of the wire feed / feed motor. It is a timing chart. The operation of the above-described conventional technique will be described with reference to FIG. First, the activation switch TS outputs an activation signal Ts shown in FIG.

The sequence control circuit SC operates when the activation signal Ts shown in FIG. 3A is at a high level,
Motor control drive signal Sc and relay switching control drive signal Sa
Is output. The motor drive circuit MC controls the rotation of the motor M to a predetermined rotation speed while the motor control drive signal Sc shown in FIG. 3B is at the high level.

[0004] A first deceleration resistor RD1 is connected to quickly decelerate the rotation speed of the motor M, and supplies a first counter electromotive force current generated when the motor M stops.
And a part of the kinetic energy is consumed as a resistance loss, thereby speeding up the rotation of the motor M.

[0005] The first deceleration relay RLY1 is shown in FIG.
(C) operates in response to the relay switching control drive signal Sa, and opens the contact of the first deceleration relay RLY1 while the relay switching control drive signal Sa is at the Low level;
Conversely, the contact of the first deceleration relay RLY1 is closed while the relay switching control drive signal Sa is at the high level.

The operation immediately after the operation of the speed control device of the wire feed / power supply motor is stopped when the motor drive cables 1 and 2 are used with the standard length of 3 m will be described. FIG.
At time t = t2 shown in (B), the activation signal Ts becomes L
When the signal goes low, the motor control drive signal Sc of the sequence control circuit SC goes low, and when the motor control drive signal Sc goes low, the motor drive circuit MC stops operating.

At time t = t2 shown in FIG. 3C, when the relay switching control drive signal Sa goes high, the contact of the first deceleration relay RLY1 is closed. At this time, the current of the back electromotive force generated by the reduction of the rotation speed of the motor M flows from the contact point of the first deceleration relay RLY1 to the first deceleration resistor RD1, and a part of the kinetic energy is consumed as resistance loss. Therefore, the rotation of the motor M is stopped in the short deceleration period Ta shown in FIG.

The operation immediately after the operation of the speed control device of the wire feed power supply motor is stopped when the length of the motor drive cables 1 and 2 is a special specification of about 30 m will be described.
As described above, the relay switching control drive signal Sa shown in FIG.
Becomes high level, the first deceleration relay RLY
One contact is closed. At this time, the rotation speed of the motor M rapidly decreases, and the current of the back electromotive force generated by the reduction of the rotation speed of the motor M is applied to the resistance values of the motor drive cables 1 and 2 and the first deceleration resistor RD1. Since the current flows and the kinetic energy is consumed as resistance loss in a divided state, the rotation of the motor M stops in the long deceleration period Tb shown in FIG.

[0009]

In the prior art speed control device for a wire feeder of a consumable electrode type welding machine shown in FIG. 2, when the motor drive cable becomes longer, the resistance value of the motor drive cable decreases by a first deceleration. Compared to the resistance value of the resistor for the motor M, the current of the back electromotive force generated by the deceleration of the rotation speed of the motor M is divided into the resistor RD1 for the first deceleration and the resistance of the cable, There is a problem that the stop time of the motor M is prolonged due to the loss. Further, the stop time of the motor M is not constant according to the length of the motor drive cable.

[0010]

SUMMARY OF THE INVENTION An apparatus according to the first aspect of the present invention is directed to a speed control device for a wire feed power supply motor of a consumable electrode type welding machine, which responds to a start signal Ts and a control cable disconnection detection comparison operation signal Cp. Output a motor control drive signal Sc and a relay switching control drive signal Sa
A relay switching control circuit SCA, a motor drive circuit MC that controls the number of revolutions of the motor M according to the motor control drive signal Sc, and a comparison of the value of the second relay drive signal Lb with a predetermined disconnection detection reference value Vr When the calculated value is larger than the predetermined disconnection detection reference value Vr (Lb <Vr), it is determined that the cable is abnormal, and the control cable disconnection detection comparison operation signal C is determined.
control cable disconnection detection comparison operation circuit CP that outputs p
And a first relay drive signal L according to the control cable disconnection detection comparison operation signal Cp and the relay switching control drive signal Sa.
a relay switching control circuit OC that outputs a and a second relay drive signal Lb, a second deceleration resistor RD2 that causes a resistance loss of the current of the electromotive force generated when the motor M decelerates, and quickly decelerates the current. 2 is a speed control device of a welding wire transmission / feed motor having a speed reduction relay RLY2 provided near a motor M.

According to the invention of the second aspect of the present invention, the welding wire according to the first aspect, wherein a first deceleration resistor RD1 and a first deceleration relay RLY1 are provided near the motor drive circuit MC. It is a speed control device of a transmission and feeding motive.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram that best illustrates the features of the invention according to the present application. Since this is the same as FIG. 4 described later, the description will be given later with reference to FIG.

An embodiment of the present invention is an invention of an apparatus according to claim 1 at the time of filing, and as shown in FIGS. 4 and 5, in a speed control apparatus of a wire feed / feed motor of a consumable electrode type welding machine, A sequence relay switching control circuit SCA for outputting a motor control driving signal Sc and a relay switching control driving signal Sa in response to a start signal Ts and a control cable disconnection detection comparison operation signal Cp, and a motor in response to the motor control driving signal Sc The motor drive circuit MC for controlling the number of rotations of M and the value of the second relay drive signal Lb are compared with a predetermined disconnection detection reference value Vr, and are compared with a predetermined disconnection detection reference value Vr (Lb <Vr). A) a control cable disconnection detection / comparison operation circuit CP which outputs a control cable disconnection detection / comparison operation signal Cp by judging that the cable is abnormal when it is large; Signal Cp and relay switch control driving signal output and first relay driving signals La and the second relay drive signal Lb in response to the Sa relay switching control circuit OC
And a second deceleration resistor RD2 that causes the current of the electromotive force generated at the time of deceleration of the motor M to lose resistance and quickly decelerate.
And a second speed reduction relay RLY2 provided in the vicinity of the motor M.

[0014]

FIG. 4 is a connection diagram of a speed control device of a wire feed / feed motor of a consumable electrode type welding machine according to the present invention. In FIG. 4, the same reference numerals as those in the connection diagram of the speed control device of the wire feed / feed motor of the conventional consumable electrode type welding machine shown in FIG. 2 and FIG. The configuration will be described.

In FIG. 4, the control cable disconnection detection comparison operation circuit CP outputs a second relay drive signal Lb determined by the ratio between the first resistor R1 and the second resistor R2 having a predetermined value. The value is compared with a predetermined disconnection detection reference value Vr set by the disconnection detection reference value setting circuit VR, and the value of the second relay drive signal Lb is set to be greater than the predetermined disconnection detection reference value Vr ( Lb <Vr) When small,
It is determined that the relay switching control cable 3 or the motor drive cable 2 is in the conductive state, and the control cable disconnection detection comparison operation signal Cp is set to the high level. Further, when the value is larger than the predetermined disconnection detection reference value Vr (Lb> Vr), it is determined that the relay switching control cable 3, the motor drive cable 2, the connector CON1 or the CON2 has a disconnection or a contact failure, and the control is performed. The cable disconnection detection comparison operation signal Cp is set to Low level.

Sequence relay switching control circuit SCA
Indicates that the control cable disconnection detection comparison operation signal Cp is High.
During the period of the level, the apparatus enters a start standby state, and outputs the motor control drive signal Sc and the relay switching control drive signal Sa in response to the start signal Ts. However, while the control cable disconnection detection comparison operation signal Cp is at the Low level, During this time, the start is prohibited, and the relay switching control drive signal Sa and the motor control drive signal Sc are set to the low level regardless of the start signal Ts.

The relay switching control circuit OC is in a start-up standby state while the control cable disconnection detection comparison operation signal Cp is at the High level, and outputs only the second relay driving signal Lb in response to the relay switching control driving signal Sa. Or Lo
The output is controlled to the w level, and the first relay drive signal La
ow level is maintained. When the control cable disconnection detection / comparison operation signal Cp goes to a low level, the start-up is prohibited and the first relay drive signal La and the second relay drive signal Lb are set to a high level.

[0018] Wire feeder WSR with deceleration resistance and relay
Is formed by a motor M, a second deceleration relay RLY2, and a second deceleration resistor RD2.

FIG. 5 is a timing chart for explaining the operation of the speed control device of the wire feed / feed motor of the consumable electrode type welding machine shown in FIG. 4. The speed control device of the wire feed / feed motor shown in FIG. Will be described with reference to the timing chart of FIG. FIG. 5A shows the activation signal Ts, and FIG.
Indicates a relay switching control drive signal Sa, and FIG.
Indicates a motor control drive signal Sc. FIG. 5D shows the second relay drive signal Lb, FIG. 5E shows the control cable disconnection detection comparison operation signal Cp, and FIG.
Shows the first relay drive signal La, and FIG.
This shows the number of rotations of the motor M.

At time t = t3 shown in FIG.
When the main power source of the welding power source WER is input, the control cable disconnection detection / comparison circuit CP immediately after the main power source is input,
The value of the second relay drive signal Lb determined by the ratio between the first resistor R1 and the second resistor R2 having a predetermined value and the predetermined disconnection set by the disconnection detection reference value setting circuit VR A comparison operation is performed with the detection reference value Vr, and the value of the second relay drive signal Lb is set to a predetermined disconnection detection reference value Vr.
Is smaller than (Lb <Vr), it is determined that the relay switching control cable 3 or the motor drive cable 2 is in the conductive state, and the control cable disconnection detection comparison operation signal Cp is set to H.
Sequence relay switching control circuit S at high level
Output to CA.

At time t = t1 shown in FIG.
When the activation signal Ts goes high, the sequence / relay switching control circuit SCA responds to the activation signal Ts.
Sets the relay switching control drive signal Sa and the motor control drive signal Sc to High level.

The relay switching control circuit OC is in a start-up standby state while the control cable disconnection detection comparison operation signal Cp is at the High level, and the relay switching control drive signal Sa is at the H level.
At the time of the high level, the second relay drive signal Lb is set to L level.
The level is set to the low level to open the contact of the second deceleration relay RLY2. Further, the first relay drive signal La becomes low level during the period when the control cable disconnection detection comparison operation signal Cp is high level, and the first deceleration relay R
The contact of LY1 is opened.

At time t = t1 shown in FIG.
When the motor control drive signal Sc becomes High level, the motor drive circuit MC starts operation and controls the rotation of the motor M to a predetermined number of rotations.

At time t = t2 shown in FIG.
When the activation signal Ts goes low, the activation signal Ts
s, the sequence / relay switching control circuit SCA
Relay switching control drive signal Sa and motor control drive signal Sc
Are set to Low level.

When the relay switching control drive signal Sa goes low, the relay switching control circuit OC outputs the signal Sa.
The second relay drive signal Lb is set to a high level in response to the control signal to set the contact of the second deceleration relay RLY2 of the wire feeder WSR with deceleration resistance / relay to "closed". Further, the motor control drive signal SC also becomes Low level, and the motor drive circuit MC stops the operation and stops the rotation of the motor M according to the signal Sc. At this time, the current of the back electromotive force generated by the reduction of the rotation speed of the motor M is passed through the contact point of the second deceleration relay RLY2 to the second deceleration resistor R
The motor M can be stopped in the short deceleration period Ta shown in FIG.

At time t = t4 shown in FIG.
When a disconnection or poor contact occurs in the relay switching control cable 3, the motor drive cable 2, the connector CON1, or the connector CON2, the control cable disconnection detection / computation circuit CP
Are the first resistor R1 and the second resistor R having predetermined values.
The value of the second relay drive signal Lb, which is determined by the ratio of the second relay drive signal Lb, is compared with a predetermined disconnection detection reference value Vr, and the value of the second relay drive signal Lb is set to the predetermined disconnection detection reference value Vr. If the value is larger than (Lb> Vr), the control cable disconnection detection / comparison operation signal Cp is determined to be a disconnection or poor contact, and is output at a low level.

When the control cable disconnection detection / comparison operation signal Cp goes low, the relay switching control circuit OC goes into a start-prohibited state, sets the second relay drive signal Lb and the first relay drive signal La to high level, and The contacts of the second deceleration relay RLY2 and the first deceleration relay RLY1 are closed.

Sequence relay switching control circuit SCA
Means that the control cable disconnection detection comparison operation signal Cp is Lo
When the signal goes to the w level, the start is prohibited, and the motor control drive signal Sc and the relay switching control drive signal Sa are set to the low level.

When the control cable disconnection detection / comparison operation signal Cp is in the low-level start prohibition state, at time t = t5 shown in FIG. 5A, the rotation of the motor M is kept stopped even if the start signal Ts is input. Become.

[0030]

According to the speed control apparatus of the wire feeding and feeding motor of the consumable electrode type welding machine of the present invention, the stop time of the motor M is always constant with respect to the variation of the length of the motor drive cable. Further, when a disconnection occurs during welding standby or during welding, the disconnection is detected by the control cable disconnection detection / comparison operation circuit CP and the start is prohibited.
Until the motor stops rotating and the disconnection condition is resolved.
Since the rotation stop of the wire is maintained, the electric shock of the wire feed at the start of the welding can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram that best represents the features of the invention according to the present application.

FIG. 2 is a connection diagram of a speed control device of a wire feeding / powering motive of a conventional consumable electrode type welding machine.

FIG. 3 is a timing chart for explaining the operation of the speed control device of the wire feed / feed motor shown in FIG. 2;

FIG. 4 is a connection diagram of a speed control device of a wire feeding / powering motive of the consumable electrode type welding machine of the present invention.

FIG. 5 is a timing chart for explaining the operation of the speed control device of the wire feed / feed motor shown in FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 motor drive cable 2 motor drive cable 3 relay switching control cable CP control cable disconnection detection comparison operation circuit CON1 power supply side connector CON2 supply side connector M motor MC motor drive circuit OC relay switching control circuit RD1 first deceleration resistor RD2 Second deceleration resistor R1 First resistor R2 Second resistor R3 Resistor RLY1 First deceleration relay RLY2 Second deceleration relay SC Sequence control circuit SCA Sequence / relay switching control circuit TS Start switch VR disconnection detection reference value setting circuit WE welding power supply WER welding power supply WS Wire feeder WSR Wire feeder with deceleration resistor / relay Cp Control cable disconnection detection comparison operation signal La First relay drive signal Lb Second relay drive signal Sa relay switching control drive signal Sc Motor control drive signal Ts Start signal Vr Disconnection detection reference value

Claims (2)

[Claims] In a speed control device for a wire feeding and feeding motor of a consumable electrode type welding machine, a sequence for outputting a motor control drive signal and a relay switching control drive signal according to a start signal and a control cable disconnection detection comparison operation signal. A relay switching control circuit, a motor drive circuit for controlling the number of rotations of the motor in accordance with the motor control drive signal, and comparing the value of the second relay drive signal with a predetermined disconnection detection reference value to calculate the predetermined value A control cable disconnection detection / computation circuit that outputs a control cable disconnection detection / comparison operation signal by determining that the cable is abnormal when the value is greater than the disconnection detection reference value; a control cable disconnection detection / comparison operation signal; A relay switching control circuit for outputting a first relay drive signal and a second relay drive signal in response to A speed control device for a welding wire transmission / feed motor having a second deceleration resistor and a second deceleration relay provided near a motor for quickly decelerating the power current by resistance loss. 2. The speed control device for a welding wire feeding and feeding motor according to claim 1, wherein a first deceleration resistor and a first deceleration relay are provided near the motor drive circuit.