Lincoln Electric INVERTEC V275-S Service Manual page 23

Section E-1
-THEORY OF OPERATION SECTION-
Theory of Operation .............................................................................................................Section E
General Description ....................................................................................................................E-2
Input Board and Bus Board ........................................................................................................E-2
Auxiliary Transformer ..................................................................................................................E-2
Main IGBT Switch Board ............................................................................................................E-3
Main Transformer ........................................................................................................................E-3
Control Board..............................................................................................................................E-4
Fans Circuit .................................................................................................................................E-4
Output Rectifier...........................................................................................................................E-5
Choke..........................................................................................................................................E-5
Thermal Protection......................................................................................................................E-6
Protective Circuits.......................................................................................................................E-6
Overcurrent Protection................................................................................................................E-6
Under/Over Voltage Protection ...................................................................................................E-6
Insulated Gate Bipolar Transistor (IGBT) Operation ...................................................................E-7
Pulse Width Modulation..............................................................................................................E-8
Minimum/Maximum Output ........................................................................................................E-8
Input Switch
Input
& 100A Breaker
Rectifier
Aux.
Trans
Fan
Relay
Fan
Fan
Motor
Motor
230VAC
230VAC
6
Pin
Amphenol
TABLE OF CONTENTS
FIGURE E.1 – V275-S BLOCK LOGIC DIAGRAM
Main Switch Board
+
Reconnect
Switch
-
-
To
Shut Down Signal
Fan
Motors
18 VAC
Relay Control
#1 Primary
Current
Feedback
To Control
Board
#2 Primary
Current
Feedback
Output
Diodes
IGBT Drive Signal
#1 Primary
Precharge Relay Control
Current
Feedback
Control Board
Hot
Arc Output
Mode
Start
Force Control
V275-S
Section E-1
Choke
Positive
+
Output
Terminal
Negative
-
Shunt
Output
Terminal
Thermostats
Thermo.
LED
Local
Remote