Lincoln Electric SVM132-A service manual GUN Trigger and 1CR Relay Contact Control Circuits

Models: SVM132-A

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E-3

THEORY OF OPERATION

E-3

 

FIGURE E.2 – GUN TRIGGER AND 1CR CONTACT CONTROL CIRCUITS

REMOTE￿

OUTPUT￿

CONTROL

#21

VARIABLE VOLTAGE￿

#567

ELECTRODE￿

 

BOARD

 

METER￿

 

 

SHUNT

 

 

 

#75￿

WIRE FEED￿

#76￿

SPEED CONTROL

#77

 

 

 

CIRCUIT￿

 

 

 

 

 

 

 

 

BREAKER

 

 

 

 

WIRE￿

THERMAL￿

INPUT￿

#32

#32A

 

CONTROL￿

ARMATURE

 

 

 

 

FEED￿

CIRCUIT￿

RECEPTACLE

 

 

 

BOARD

 

 

MOTOR

BREAKER

 

#31

 

 

 

 

 

 

 

#2￿

 

 

 

 

 

 

 

 

&￿

 

2 OHMS

 

#3￿

 

 

 

 

#4￿

 

 

 

2￿

 

 

 

 

￿

 

 

 

 

 

 

 

 

 

 

A

 

 

 

 

C￿

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

O￿

 

 

 

 

 

 

 

 

N￿

 

 

 

 

 

 

 

 

T￿

 

 

 

 

 

 

 

 

A￿

 

 

 

 

 

 

 

 

C￿

 

#531

 

 

 

FIELD

 

 

T￿

 

FUSE

 

 

 

 

 

 

 

 

 

 

O￿

 

 

 

 

 

 

 

 

R

 

 

 

 

RELAY￿

 

 

 

 

 

 

 

 

 

 

 

CONTROL

 

 

 

BOARD

 

 

 

 

 

 

 

 

GUN ￿

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CABLE ￿

 

 

 

 

 

 

 

RECEPTACLE

 

OPTIONAL￿

 

 

 

 

 

 

 

BURNBACK￿

 

 

 

 

 

 

 

BOARD

 

 

 

 

 

 

 

 

GLP

REED￿

TRIGGER￿

WIRE￿

INTERLOCK￿

 

 

 

 

FEED￿

 

 

 

 

SWITCH

TRANS.

SWITCH

 

 

 

 

 

SWITCH

 

 

 

 

 

 

 

 

 

 

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GUN TRIGGER AND 1CR RELAY CONTACT CONTROL CIRCUITS

When the gun trigger switch is activat- ed (closed) the 1CR relay is energized. Three sets of isolated contacts incor- porated within the 1CR relay perform several functions. One set of contacts completes the circuit to energize the wire feed motor armature and also the auxiliary circuit #7 and #32A. Another set of contacts control the motor field circuit polarity which, along with the wire feed switch, dictate the wire feed direction. The third set of contacts control the #2 and #4 contactor circuit

which enables the power source weld- ing output. The #2 and #4 contactor circuit is passed through the optional burnback board which delays the “opening” of the circuit and prevents the electrode from “sticking” in the weld puddle.

The interlock switch, reed switch, ground lead protector (GLP), and ther- mal circuit breaker are all incorporated in the gun trigger circuit. In case of a fault condition, the GLP or thermal cir- cuit breaker will disable the trigger cir- cuit. The interlock switch and reed switch enhance the gun trigger circuitry by allowing the operator to release the trigger button and continue welding.

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NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

LN-8

Page 47
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Lincoln Electric SVM132-A service manual GUN Trigger and 1CR Relay Contact Control Circuits