THEORY OF OPERATION
E-4 E-4
COMMANDER 300
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CONTROL TRANSFORMER AND
CONTROL BOARD
The control transformer primary winding is powered by
the 115VAC auxiliary coil in the stator. Three sec-
ondary voltages are developed by the control trans-
former. The 42VAC is applied to the control board
where it is rectified and used to operate the control
board circuitry. The two isolated 30VAC windings sup-
ply power to the IGBT driver circuits.
The control board monitors the operator controls (out-
put, mode selector and arc control). It compares these
commands to the current and voltage feedback infor-
mation it receives from the shunt and output terminals.
The circuitry on the control board determines how the
output should be controlled to optimize welding results
and sends the correct PWM signals to the IGBT driver
circuits.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
FIGURE E.4 – CONTROL TRANSFORMER AND CONTROL BOARD