Lincoln Electric SVM158-A service manual Theory of Operation

Output Potentiometer

GENERAL DESCRIPTION

The Invertec V350-Pro is an inverter based welding power source that offers multi mode constant voltage (CV) and constant current (CC) welding and is rated at 350 amps 34VDC at a 60% duty cycle. The Invertec V350-Pro is available in a construction version (no wire feeder connection or auxiliary power ), a factory ver- sion that includes a wire feeder connection and relat- ed power, an advanced process version and a rack version.

INPUT LINE VOLTAGE, AUXILIARY TRANSFORMER, & PRECHARGE

The Invertec V350-Pro can be connected for a variety of three-phase or single-phase input voltages. The ini- tial power is applied to the V350 through a line switch located on the front of the machine. Two phases of the input voltage are applied to the auxiliary transformer. The auxiliary transformer develops four different sec- ondary voltages. The 115VAC is used to power the fan motor and also is applied to the 14 pin amphenol type connector for wirefeeder operation. The 24VAC and 42VAC voltages are also applied to the 14 pin amphe- nol type connector to power wirefeeders. The 28VAC

Return to Section TOC

Return to Section TOC

Return to Section TOC

Return to Section TOC

Return to Master TOC

Return to Master TOC

Return to Master TOC

Return to Master TOC

E-2		THEORY OF OPERATION							E-2
		FIGURE E.2 – INPUT VOLTAGE AND PRECHARGE
			Main Switch Board					To Control
								Board
								Feedback	Current
	Input								Positive
Input switch				Primary					Output
	Rectifier								Terminal
				Current
				Sensor
		Reconnect						Choke	Negative
									Output
		Switch							Terminal
				Primary				Sense
				Current
				Sensor
		Fan
								VoltageOutput
		115VAC Fan Supply	ControlFan	Primary Current Feedback			IGBTDrive Signal
				Input Relay Control
Auxiliary				Soft Start Control
115VAC, 42VAC Transformer				V/F Capacitor Feedback (2)
24VAC
		Machine Control Supply
		+15VDC, -15VDC, +5VDC
		Power
28VAC		Board SPI Supply +15VDC +5VDC					Control Board
	40VDC
14 Pin		RS232 Supply +5VDC
									RS232
Amphenol
				SPI Communications				& +15VDC, +5VDC Supply
		Remote Control & Trigger Remote				Mode		Advanced
						Panel		Display	Process
				Board				Panel
						(Not used if APP			Panel
						is in place)
6 Pin				12
				VDC
Amphenol
			Output	Weld	Optional Solenoid
			Control	Terminals

is rectified and the resultant 40VDC is applied to the power board.

The input voltage is rectified by the input rectifier and the resultant DC voltage is applied to the switch board through the reconnect switch assembly located at the rear of the machine. The reconnect switch connect the two pairs of input capacitors either in a parallel (lower voltage) or series (higher voltage) configuration to accommodate the applied input voltage.

During the precharge time the DC input voltage is applied to the input capacitors through a current limit- ing circuit. The input capacitors are charged slowly and current limited. A voltage to frequency converter circuit located on the switch board monitors the capacitor voltages. This signal is coupled to the con- trol board (measure frequency, not voltage to check signal). When the input capacitors have charged to an acceptable level, the control board energizes the input relays, that are located on the switch board, making all of the input power, without current limiting, available to the input capacitors. If the capacitors become under or over voltage the control board will de-ener- gize the input relays and the V350 output will be dis- abled. Other possible faults may also cause the input relays to drop out.

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

V350-PRO