Inverter Board (Inverter-Output) - Lincoln Electric INVERTEC 160SX Service Manual

INVERTER BOARD (INVERTER-OUTPUT)

INVERTER BOARD, MAIN
TRANSFORMER, OUTPUT RECTIFIER,
AND OUPUT CURRENT PROBE
When the input filter capacitors are fully charged
they act as power supplies for the IGBT switching
circuit.
The IGBTs supply the main transformer winding
with 70KHz current flow.
The IGBTs act as a switch assembly. This
assembly feeds the primary winding of the main
transformer. When current is pulsed through this
primary winding, a resultant current is produced
on a secondary winding of the main transformer.
Current transformer located on the inverter board
monitor the primary current. If the primary current
become abnormally high, the inverter control
circuit will shut off the IGBTs, thus disabling the
machine's output.
A thermal protector is also present, to the inverter
heatsink, to protect the IGBTs from overheating
conditions and to the output rectifier bridge
heatsink.
The main transformer, located outside the inverter
board, insulate the primary circuit from the
secondary circuit.
The output circuit is also part of the Inverter board
and the 4 rectifier modules receive the high
frequency AC output from the main transformer
secondary winding and rectifies it to a DC voltage
level. A doubler circuit increase the output voltage
to be able to perform cellulosic welding; a filtered
DC output is applied to the machine's output
terminals
.
An output hall current probe read the output
current and send the signal to the analog control
loop that manage the output current.
Page13