Lincoln Electric SVM123-A service manual Input Line VOLTAGE, Contac, TOR, and Main Transformer

E-2 THEORY OF OPERATION E-2

TOC	TOC	GENERAL DESCRIPTION
Section	Master	The DC 1000 is an SCR - controlled DC power		range potentiometer ouptut control. It can be used
		source. It is designed to be controlled with a single		for submerged arc or open arc automatic and semi-
				automatic welding.
to	to
Return	Return		FIGURE E.2 - Input Line Voltage, Contactor and Main Transformer
Return to Section TOC	Return to Master TOC
to Section TOC	to Master TOC	INPUT LINE VOLTAGE, CONTAC-
Return	Return
		TOR, AND MAIN TRANSFORMER
		The desired three phase power is connected to the		age, low current input power to a low voltage, high
		DC-1000 through an Input Contactor located in the		current output. The finishes or “neutrals” of the
		input box at the rear of the machine. Two phases of the		main secondary coils are connected together and
		input lines are also connected to the Control		the six starts of the secondary windings are con-
		Transformer which supplies power to the Contactor		nected to the rectifier assembly. In addition, the
		Hold-In Circuit. The Contactor Hold-In Circuit will dis-		main transformer also has an isolated 115 VAC
		able the Input Contactor if the DC-1000 is overloaded		auxiliary winding that supplies 115 VAC to operate
TOC	TOC	or overheated.		the cooling fan and offers 8 amps of auxiliary power
		A Reconnect Panel allows the user to configure the		to operate wire feeding equipment. The three 75
				VAC phase angle windings are also housed in the
		machine for the desired input voltage. This AC input
to Section	to Master			Main Transformer assembly. These windings pro-
		voltage	is applied to the primary of the Main
				vide power and “timing” to the Firing Board.
		Transformer. The transformer changes the high volt-
Return	Return		NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

IDEALARC DC-1000