Theory Of Operation; General Description; Input Line Voltage And Auxiliary Transformer - Lincoln Electric PRO-CUT 25 Service Manual

E-2
SW1
L1 RL3
A
300uH R1
10/10W
B
V1
L1
V2
230V
RL1
115V
L1
Input
Voltage Board
12VDC
Air
Purge
Solenoid
Switch
1

GENERAL DESCRIPTION

The PRO-CUT 25 is an inverter based constant
current, continuous control plasma cutting power
source. The control system has a safety mechanism
to insure that the nozzle and electrode are in place
before cutting or gouging. The PRO-CUT 25 initiates
the plasma arc with a simple, yet reliable, touch start
mechanism. This system eliminates many of the prob-
lems associated with hi-frequency type start systems.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.

THEORY OF OPERATION

FIGURE E.2 – INPUT LINE VOLTAGE
AC
AC
RL2
CP CP
RL2
CP CP
RL2
AC AC
RL1
RL2
115VAC
T1
CN1 CN2
15VAC
1 9
15VAC
2 10
SAFETY
3 5
+28VDC
4 6
SEC GND
5 3
OVLOAD
6 22
115/230
7 2
+12VDC
8 20
15 16
8 6 17 9 3
CN1
Display LED's
Control Board
PRO-CUT 25
Q1a,b,c
IRG4BC30W
C26
T2
PRI
+
R1
CP
C1a,b
C12
CP
+
R2
C2a,b
Q2a,b,c
IRG4BC30W
C13
CN1
12 18 14 1 11 4 13 7 19 24 21 23 8 17 1 2 3
1 2 18 14 7 15 4 11 5 16 10 12 13 23 22 24
Output Control
INPUT LINE VOLTAGE, AND
AUXILIARY TRANSFORMER
The single-phase input power of 115 230 Volts AC is
connected to the machine, via an input cord, to a
switch located on the front panel.
The PRO-CUT 25 Input voltage board automatically
reconnects the auxiliary and inverter connections to
configure the machine for either a low 115V AC or high
230V AC input voltage.
develops the appropriate AC voltages to operate the
cooling fan, the control board, and the inverter board.
Lout
D10
BS1
WRK
240uH
8A
+12VDC TRANSFER
SEC
D11
RL1 NZL (2)
C14
R24
6.8k/5W
SHUNT
EL (3)
SH- SH+
CN3
1
2
3
4
Main Inverter Board
4
The auxiliary transformer
E-2
WORK CLAMP
PT
12VDC