Theory Of Operation Effective With Lb141715 - Miller Syncrowave 250 DX Technical Manual

5-2. Theory Of Operation Effective With LB141715

1 Input Terminal Board TE1
Provides means for operation on
different input voltages.
2 Power Switch S1
Provides on/off control of welding
power source.
3 Main Transformer T1
Supplies power to weld output cir-
cuit, various control circuits, main
control board PC1, and fan motors
FM1 and FM2.
4 Main Rectifier
Changes the ac output from T1 to
full-wave rectified dc and controls
output current level.
5 Fan Motors FM1, FM2
Provides cooling of internal compo-
nents.
6 115 VAC Duplex Receptacle
RC2
Provides connection point for aux
iliary equipment.
7 Circuit Breaker CB1
Protects 115 volts AC winding.
8 Control Board PC1
Controls weld output by changing
the SCR gate pulses (conduction
times) after comparing current
feedback to selected amperage
signal. Also provides user inter-
face.
9 Thermistor TH1
Provides temperature feedback
about the rectifier back to control
board PC1.
10 Thermistor TH2
Provides temperature feedback to
the control board PC1 about main
transformer T1.
11 Remote 14 Receptacle RC1
Provides connect point for remote
amperage and contactor devices.
12 Gas Valve GS1
Provides control of shielding gas.
13 Automation 10-Pin
Receptacle RC3
Provides a connection point for op-
tional Automation 10-pin.
TM-359 Page 56
1
Input
Single-Phase
Terminal
Line Input
Board TE1
Power
5
Fan Motors
FM1, FM2
8
9
Thermistor
TH1
10
Thermistor
TH2
11
Remote 14-Pin
Receptacle RC1
2 3
φ φ
1 1
Power
Transformer
Switch S1
6 7
115 VAC Duplex
Circuit
Receptacle
Breaker
CB1
RC2
Control Board PC1
12
Gas Valve
GS1
Main
T1
DC
4
Main
Rectifier
♦
13
Automation 10-Pin
Receptacle RC3
Syncrowave 250 DX