Main Transformer - Lincoln Electric INVERTEC SVM161-A Service Manual

E-4
FIGURE E.4 - MAIN TRANSFORMER, OUTPUT DIODE MODULE & CLAMPING BOARD,
OUTPUT TRANSISTOR MODULE & SUPERIMPOSITION BOARD
Fan
Superimposition
board
24 VDC
Bus board
Input
board
Main IGBT
& Power board
Input
Choke
HF control signal
+48, +24
48 VDC
Gas
Solenoid

MAIN TRANSFORMER

The 100KHZ output of the Main IGBT Inverter Board is
coupled, through a DC Blocking Capacitor Board, to
the primary of the Main Transformer. The transformer
reduces the high voltage (low current) input applied to
the primary winding and through transformer action
develops a lower secondary voltage capable of high
output currents.
OUTPUT MODULE AND CLAMPING
BOARD
The AC output of the Main Transformer is applied to
the Output Modules for full wave rectification. The
Clamping Diodes function as a filter eliminating any
pulsed over-voltages that may be present at the Output
Modules. The Clamping Board protects the Output
Modules from damage due to higher than normal volt-
age spikes.
THEORY OF OPERATION
AC DC Gate drive signals
HF
board
Voltage Feedback
Current Feedback
IGBT
Thermostat
Thermostats
4
IGBT's
DC blocking
capacitor board
Main
Transformer
24 VDC Remote 2/4 path (D + E)
Display & LED
Control board
board
OUTPUT MODULE TRANSISTOR
BOARD
This module produces the AC waveforms and frequen-
cies.
Superimposition Board. Depending on which of the
two IGBTs is active at any given moment the welding
output of the machine can be either positive or nega-
tive AC or DC.
SUPERIMPOSITION BOARD
The Super Imposition Board receives signals from the
Control/Display Board to control the status of the sec-
ondary inverter portion of the V205T machine. This
board also generates voltage pulses at about +/-
200VDC that facilitate the re-striking of the arc when
the TIG AC welding current is being utilized.
Superimposition Board internally generates the auxil-
iary power supply for the isolated piloting of the power
elements (IGBTs) for the Output Module Transistor
Board. The Superimposition Board plugs directly into
the Bus Board.
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
INVERTEC® V205-T AC/DC™
Output
Diode
Current
Hall
Output
Device
Output
Transistor
board
Module
888
Control
Knob
It receives command signals from the
E-4
Output
Filter bd.
(bypass)
_
Output RF coil
Choke
+
(D + E)
Remote 2/4
Remote
75, 76, 77
A, B, C
The