Lincoln Electric POWER WAVE 355M - Manual (Page 39)

TABLE OF CONTENTS-THEORY OF OPERATION SECTION E-1 E-1
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POWER WAVE 355M/405M
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E-1
General Description ...................................................................................................................................E-2
Input Line Voltage, Auxiliary Transformer and Precharge..........................................................................E-2
Switch Board and Main Transformer .........................................................................................................E-3
DC Bus Board, Power board and Control Board ......................................................................................E-4
Output Rectifier and Choke .......................................................................................................................E-5
Thermal Protection ...................................................................................................................................E-6
Protective Circuits......................................................................................................................................E-6
Over current 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
FIGURE E.1 BLOCK LOGIC DIAGRAM
Control Board
Choke
Positive
Output
Terminal
Negative
Output
Terminal
To Control
Board
C
u
rr
e
n
t
F
e
e
d
b
a
c
k
Reconnect
Switch
O
u
tp
u
t
V
o
lt
a
g
e
S
e
n
s
e
Input switch
Input
Rectifier
Auxiliary
Transformer
Fan
Power
Board
220
Receptacle
RS232 Supply +5VDC
Machine Control Supply
+15VDC, -15VDC, +5VDC
40VDC
42VAC
220 VAC
Main Switch Board
115VAC Fan Supply
F
a
n
C
o
n
tr
o
l
V/F Capacitor Feedback (2)
Soft Start Control
Input Relay Control
Primary Current Feedback(2)
IG
B
T
D
riv
e
S
ig
n
a
l
Primary
Current
Sensor
Primary
Current
Sensor
{ P
o
w
e
r
W
a
v
e
4
0
5
o
n
l
y
6
5
V
A
C
DC
Bus
Board Wire
Feeder
Recp.
40VDC
Can Supply +5VDC
Arc
Link
Electrode
Sense 21 Lead
Voltage
Sense
Recp.
R232
Connector
Yellow
Thermal
LED
Status
Red/Green
LED
Thermostats
2
To
Feeder