Lincoln Electric COMMANDER 400 SVM133-B Service Manual page 51

E-3
FIGURE E.3 – EXCITER FEEDBACK, CONTROL BOARD, LOCAL AND REMOTE CONTROL
STARTER
ALTERNATOR
ENGINE
SHUTDOWN
SOLENOID
IDLER
SOLENOID
BATTERY
ENGINE
SENSORS
EXCITER FEEDBACK, CONTROL
BOARD, LOCAL AND REMOTE
CONTROL
The exciter voltage is monitored and fed back through
the exciter voltage feedback board to the control board.
In the event the exciter voltage increases or decreases
to an unacceptable level, the engine protection circuit
shuts off the engine.
The control board compares the commands of the cur-
rent/mode selector and the fine output control (or
remote control) with the output voltage and current
feedback and sends the appropriate SCR gate firing
signals to the SCR/Diode bridge.
NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.
THEORY OF OPERATION
MECHANICAL
ROTOR
ROTATION
EXCITER
WINDINGS
115VAC
EXCITER
14 PIN
CAPACITORS
AMPHENOL
115/230VAC
BY-PASS
RECEPTACLE
PC
6 PIN BOARD
AMPHENOL
EXCITER VOLTAGE
FEEDBACK
BOARD
COMMANDER 400
SCR/DIODE
OUTPUT
OUTPUT
CHOKE
BRIDGE
SCR GATE SIGNALS
42VAC
REMOTE
SWITCH
FINE
OUTPUT
CONTROL
12VDC
The Commander 400 is controlled by a high quality
microcontroller, which is the main circuit element of the
control board.
The control board also supplies operating voltages and
control signals to the CV board, the meter board, and
the engine protection board.
The remote control and contactor signals are fed to the
control board through the amphenols and the by-pass
board.
E-3
NEGATIVE
TERMINAL
CV
TERMINAL
SHUNT
POSITIVE
TERMINAL
F
E
FEEDBACK
E
D
B
A
C
K
CV
BOARD
METER
MAIN
CONTROL
BOARD
ENGINE
PROTECTION
BOARD
CURRENT/ MODE
SELECTOR
SWITCH