Thermal and Overload Protection | Lincoln Electric SVM157-A specs

E-5

THEORY OF OPERATION

E-5

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

PROTECTIVE DEVICES AND CIRCUITS

THERMAL AND OVERLOAD PROTECTION

The POWER MIG 200 has two built-in protective thermostats that respond to excessive temperatures. One is located on the main transformer. The other thermostat is located on the output rectifier heat sink assembly. They open the wire feed and welder output circuits if the machine exceeds the maximum safe operating temperature. This can be caused by a frequent overload or high ambient temperature.

The thermostats are self-resetting once the machine cools sufficiently. If the thermostat shutdown is caused by excessive output or duty cycle and the fan is operating normally, the power switch may be left on and the reset should occur within a 15 minute period. If the fan is not turning or the air intake louver are obstructed, then the input power must be removed and the fan problem or air obstruction must be corrected.

WIREFEED OVERLOAD PROTECTION

The POWER MIG 200 has solid state overload protection of the wire drive motor. If the motor becomes overloaded, the protection circuitry turns off the wire feed speed and gas solenoid. Check for proper size tip liner, drive rolls, and any obstructions or bends in the gun cable. Check for any other factors that would impede the wire feeding. To resume welding, simply pull the trigger. There is no circuit breaker to reset, as the protection is done with reliable solid state electronics.

POWER MIG 200

Image 33

Lincoln Electric SVM157-A service manual Thermal and Overload Protection, Wirefeed Overload Protection

Contents

Safety Depends on You Power MIG California Proposition 65 Warnings Safety ARC Rays can burn Electric Shock can kill Iii Cylinder may explode if damaged Sûreté Pour Soudage a L’Arc Précautions DE Sûreté Master Table of Contents for ALL Sections Installation Section Table of Contents Technical Specifications Power MIG Installation 3INSTALLATIONA-3 Figure A.1 Dual Voltage Machine Input Connections Figure A.2 Triple Voltage Machine Input Connections Output Polarity Connections GUN and Cable Installation Shielding GASCylinder may explode if damaged Operation Section B Operation Section Wear eye, ear and body protec- tion Operation Wire Size Conversion Parts Wire Drive RollProduct Description Recommended Processes and Equipment Procedure for Changing Drive and Idle Roll Sets Wire Reel Loading READI-REELS, Spools or CoilsTo Start the Welder Idle Roll Pressure Setting Feeding Wire Electrode Making a Weld Wire Feed Overload Protection Avoiding Wire Feeding ProblemsFAN Control Input Line Voltage Variations Accessories Section Drive Roll Kits AccessoriesK363P READI-REEL Adapter Dual Cylinder Mounting KIT K1702-1 Adapter KIT and Spool GUN Installed Power MIG Maintenance Section Maintenance Liner Removal and REPLACE- Ment Cause poor wire feedingThis screw should only be gently tightened Overtightening will split or collapse the liner English Metric Description Size GUN Handle Disassembly Maintenance Power MIG Theory of Operation Section Line Switch Theory of Operation Motor Control Board Output Rectification Contactor and Control Board Figure E.4 Optional Circuits Control BOARD, GUN Trigger and Wire Drive Motor Thermal and Overload Protection Wirefeed Overload Protection Power MIG Troubleshooting and Repair Section F Troubleshooting and Repair Section How To Use Troubleshooting Guide Troubleshooting and Repair PC Board Troubleshooting Procedures Perform the Main Transformer Perform the Output Contactor These capacitors is toxic Avoid contact with any portionYour body Function Problems Tachometer Feedback Test Welding Problems Weld bead is narrow or ropy Make sure the welding proce Main Transformer Test Test DescriptionMaterials Needed Main Transformer Test ON/OFF Power Switch will be hot during these tests X10 Input Voltage Test Points Table F.1. Test Points Wire Drive Motor and Tachometer Feedback Test Figure F.4. Plug J4 Test Procedure Test for Supply Voltage to Tachometer Disconnect the main AC input power to the machine VDC Test for Feedback Voltage to Control Board Output Bridge Rectifier Test Output Bridge Rectifier Test Test Procedure Contactor Test Figure F.7. Contactor Terminals and Leads Contactor Test Typical Output Voltage Waveform Machine Loaded MAX TAP G Volts 10.0 Normal Open Circuit Voltage Waveform MAX TAP G Volts 20.0 Machine Loaded to 180 Amps AT 16 VDC Scope Settings Volts 20.0 Description Control Board Replacement Procedure Control Board Replacement Wire Drive Motor Assembly Replacement Wire Drive Wire Drive Motor Assembly Replacement Bolt Gas Hose TOC Output Diode Bridge Rectifier Replacement Output Diode Bridge Rectifier Mounting Bracket Mounting Bolts Rectifier Power MIG Output Capacitors Replacement Figure F.14. Capacitor Bank Location Output Capacitors Replacement Lead Mounting Bolts Nuts & Lock washers Places Power MIG Main Transformer Replacement 41TROUBLESHOOTING and REPAIRF-41 See Figure F.17 Main Transformer Replacement Figure F.17. Leads X9, X10, 104B,104C, & H1B Replacement X2 X3 X4 X5 X6 X7 Lead Power MIG FAN BLADE/MOTOR Replacement Perform the Output Capacitor Bank Removal Procedure FAN BLADE/MOTOR Replacement Output Contactor Replacement Figure F.24 Output Contactor Replacement Mounting Bolts Retest After Repair Table of Contents Electrical Diagrams Section Electrical Diagrams Wiring Diagram Power MIG 200 208/230V Schematic Control PC Board G3851-1 PC Board ASSEMBLY-CONTROL SVM Error Reporting Form