E-1

THEORY OF OPERATION

E-1

 

 

to Section TOC

to Master TOC

 

INPUT LINE VOLTAGE AND MAIN TRANSFORMER

 

 

 

 

 

 

Return

Return

 

WIRE

GAS

 

 

 

 

SPEED

SOLENOID

 

 

 

 

 

 

 

WIRE

 

 

 

 

 

 

 

DRIVE

 

 

 

ARC

 

 

 

MOTOR

 

 

 

VOLTAGE

 

 

 

 

 

 

 

CONTROL BOARD

 

 

 

 

 

 

 

G

 

 

TACH

 

 

 

 

 

 

 

 

 

 

 

A

 

 

 

 

 

 

 

T

 

GUN TRIGGER AND THUMB SWITCH

 

 

LINE

MAIN

E

 

 

 

S

 

 

 

 

 

TRANSFORMER

 

 

 

 

 

SWITCH

I

 

 

FEEDBACK

 

 

 

 

G

 

 

 

 

 

 

N

 

 

 

TOC

 

 

 

A

 

 

 

TOC

 

 

L

 

 

 

 

RECONNECT

 

 

 

POSITIVE

 

 

 

 

 

Section

Master

 

 

 

 

 

 

 

 

 

 

TERMINAL

 

 

 

C

 

CHOKE

 

 

 

 

 

 

 

 

A

F

 

 

 

 

P

E

 

 

 

 

A

E

 

to

to

 

 

 

 

 

 

 

C

D

 

 

SCR

I

B

 

Return

Return

 

RECTIFIER

T

A

 

 

 

 

O

C

 

 

FAN

 

R

K

NEGATIVE

 

 

S

 

 

MOTORS

 

 

TERMINAL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SHUNT

 

Figure E.2 - Input Line Voltage and Main Transformer.

TOC

TOC

INPUT LINE VOLTAGE AND MAIN

 

 

Section

Master

TRANSFORMER

The desired single phase input power is connected to

to

to

the WIRE-MATIC 250 through a line switch located on

Return

Return

A reconnect panel allows the user to configure the

 

 

the front panel.

 

 

machine for the desired input voltage. This AC input

 

 

voltage is applied to the primary of the main trans-

 

 

former and to the thermostatically controlled fan

 

 

motors. The transformer changes the high voltage, low

 

 

current input power to a low voltage, high current out-

 

 

put. In addition, the main transformer also has an iso-

 

 

lated center tapped 30 VAC auxiliary winding that sup-

TOC

TOC

plies power to the Control Board for SCR gate drive

and gas solenoid operation. The weld power windings

 

 

Section

Master

connect to the Control Board as well as to the main

SCR Rectifier.

 

 

 

 

 

 

to

to

 

NOTE: Unshaded areas of Block Logic

 

Diagram are the subject of discussion

Return

Return

 

 

 

 

WIRE-MATIC 250

 

 

 

Page 46
Image 46
Lincoln Electric SVM 117-A service manual Input Line Voltage and Main, Transformer