Figure E.4 Optional Circuits | Lincoln Electric SVM157-A specification

E-4

THEORY OF OPERATION

E-4

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FIGURE E.4 – OPTIONAL CIRCUITS.

			WIRE
	GAS		SPEED
	SOLENOID		CONTROL
			WIRE
			DRIVE
			MOTOR
	CONTROL BOARD
FAN	RECTIFIER
MOTOR	DIODE			TRANSFORMER	OUTPUT BRIDGE
	BRIDGE		TACH	TRANSFORMER	OUTPUT BRIDGE
	28VAC	CONTACTOR CONTROL	FEEDBACK	THERMOSTAT	THERMOSTAT
LINE	28VAC	CONTACTOR CONTROL	GUN TRIGGER
SWITCH	TAP SELECTOR		GUN TRIGGER
	TAP SELECTOR
	SWITCH
	SWITCH
			OUTPUT DIODE
			BRIDGE
			+	+
			OUTPUT	POSITIVE
			CHOKE	POSITIVE
			CHOKE	TERMINAL
				TERMINAL
		CONTACTOR	OUTPUT
			CAPACITORS
RECONNECT			-	-
RECONNECT	MAIN			NEGATIVE
PANEL	TRANSFORMER			NEGATIVE
PANEL	TRANSFORMER			TERMINAL
				TERMINAL

GUN

ASSEMBLY

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CONTROL BOARD, GUN

TRIGGER AND WIRE DRIVE

MOTOR

When the control board receives an activation command from the trigger circuit the control board activates the gas solenoid, output contactor, and the wire drive motor. The control board monitors the motor’s tach feedback signals and compares these to the wire speed control setting. The proper armature voltage is then applied to the wire drive motor. The drive motor speed is thus controlled which in turn regulates the electrode wire feed speed through the gun.

Two thermostats are included in the trigger circuitry. If either of these thermostats would “open”, the trigger circuit would be interrupted and the machine’s output would be disabled.

NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

POWER MIG 200

Image 32

Lincoln Electric SVM157-A service manual Control BOARD, GUN Trigger and Wire Drive Motor, Figure E.4 Optional Circuits

Contents

Power MIG Safety Depends on You Safety California Proposition 65 Warnings Electric Shock can kill ARC Rays can burn Cylinder may explode if damaged Iii Précautions DE Sûreté Sûreté Pour Soudage a L’Arc Master Table of Contents for ALL Sections Table of Contents Installation Section Installation Technical Specifications Power MIG 3INSTALLATIONA-3 Figure A.1 Dual Voltage Machine Input Connections Output Polarity Connections Figure A.2 Triple Voltage Machine Input Connections Cylinder may explode if damaged GUN and Cable InstallationShielding GAS Operation Section Operation Section B Operation Wear eye, ear and body protec- tion Wire Drive Roll Wire Size Conversion PartsProduct Description Recommended Processes and Equipment To Start the Welder Procedure for Changing Drive and Idle Roll SetsWire Reel Loading READI-REELS, Spools or Coils Feeding Wire Electrode Making a Weld Idle Roll Pressure Setting Avoiding Wire Feeding Problems Wire Feed Overload ProtectionFAN Control Input Line Voltage Variations Accessories Section Accessories Drive Roll KitsK363P READI-REEL Adapter Dual Cylinder Mounting KIT K1702-1 Installed Adapter KIT and Spool GUN Power MIG Maintenance Section Maintenance Cause poor wire feeding Liner Removal and REPLACE- MentThis screw should only be gently tightened Overtightening will split or collapse the liner GUN Handle Disassembly English Metric Description Size Maintenance Power MIG Line Switch Theory of Operation Section Theory of Operation Output Rectification Contactor and Control Board Motor Control Board Control BOARD, GUN Trigger and Wire Drive Motor Figure E.4 Optional Circuits Wirefeed Overload Protection Thermal and Overload Protection Power MIG Troubleshooting and Repair Section Troubleshooting and Repair Section F Troubleshooting and Repair How To Use Troubleshooting Guide PC Board Troubleshooting Procedures Perform the Main Transformer Perform the Output Contactor Your body These capacitors is toxicAvoid contact with any portion Function Problems Tachometer Feedback Test Welding Problems Weld bead is narrow or ropy Make sure the welding proce Materials Needed Main Transformer TestTest Description ON/OFF Power Switch will be hot during these tests Main Transformer Test X10 Table F.1. Test Points Input Voltage Test Points Wire Drive Motor and Tachometer Feedback Test Test Procedure Figure F.4. Plug J4 Disconnect the main AC input power to the machine Test for Supply Voltage to Tachometer Test for Feedback Voltage to Control Board VDC Output Bridge Rectifier Test Test Procedure Output Bridge Rectifier Test Contactor Test Contactor Test Figure F.7. Contactor Terminals and Leads Volts 10.0 Typical Output Voltage Waveform Machine Loaded MAX TAP G Volts 20.0 Normal Open Circuit Voltage Waveform MAX TAP G Machine Loaded to 180 Amps AT 16 VDC Scope Settings Volts 20.0 Control Board Replacement Description Control Board Replacement Procedure Wire Drive Motor Assembly Replacement Wire Drive Motor Assembly Replacement Wire Drive Bolt Gas Hose TOC Output Diode Bridge Rectifier Replacement Output Diode Bridge Rectifier Mounting Bracket Mounting Bolts Rectifier Power MIG Output Capacitors Replacement Output Capacitors Replacement Figure F.14. Capacitor Bank Location Lead Mounting Bolts Nuts & Lock washers Places Power MIG 41TROUBLESHOOTING and REPAIRF-41 Main Transformer Replacement Main Transformer Replacement See Figure F.17 Replacement Figure F.17. Leads X9, X10, 104B,104C, & H1B X2 X3 X4 X5 X6 X7 Lead Power MIG FAN BLADE/MOTOR Replacement FAN BLADE/MOTOR Replacement Perform the Output Capacitor Bank Removal Procedure Output Contactor Replacement Output Contactor Replacement Figure F.24 Mounting Bolts Retest After Repair Electrical Diagrams Table of Contents Electrical Diagrams Section Power MIG 200 208/230V Wiring Diagram Schematic Control PC Board PC Board ASSEMBLY-CONTROL G3851-1 SVM Error Reporting Form