Lincoln Electric SVM133-B service manual Itors

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E-3 E-3

THEORY OF OPERATION

FIGURE E.3 – EXCITER FEEDBACK, CONTROL BOARD, LOCAL AND REMOTE CONTROL

SCR/DIODE		OUTPUT
OUTPUT
		CHOKE
BRIDGE
		NEGATIVE
CV	ITORS	TERMINAL
		CV
CAPAC		TERMINAL
		SHUNT

POSITIVE

TERMINAL

		WINDINGS		F
				B
	WELD		FEEDBACK	E
				E
STARTER				D
				A
				C
ALTERNATOR				K

ENGINE	MECHANICAL	ROTOR		SCR GATE SIGNALS
	ROTATION
SHUTDOWN
SOLENOID
		EXCITER
		WINDINGS
	IDLER				CV
					BOARD
BATTERY	SOLENOID
				42VAC
			115VAC		METER
	EXCITER		14 PIN		MAIN
	CAPACITORS			REMOTE	CONTROL
			AMPHENOL
	115/230VAC			SWITCH	BOARD
				BY-PASS
	RECEPTACLE			PC
			6 PIN	BOARD
			AMPHENOL
				FINE
ENGINE				OUTPUT	ENGINE
SENSORS				CONTROL
					PROTECTION

BOARD

EXCITER VOLTAGE

FEEDBACK

BOARD

CURRENT/ MODE

SELECTOR

SWITCH

12VDC

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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.

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.

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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion.

COMMANDER 400