Lincoln Electric SVM134-A service manual Control of Welding Current, Figure B.2 Current Controls

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B-5

B-5

OPERATION

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CONTROL OF WELDING CURRENT

CAUTION

•DO NOT turn the CURRENT RANGE SELECTOR while welding because the current may arc between the contacts and damage the switch.

•DO NOT attempt to set the CURRENT RANGE SELECTOR between the five points designated on the nameplate.

See Figure B.2. The CURRENT RANGE SELECTOR provides five overlapping current ranges. The FINE CURRENT ADJUSTMENT adjusts the current from minimum to maximum within each range. Open circuit voltage is also controlled by the FINE CURRENT ADJUSTMENT, permitting control of the arc character- istics.

A high open circuit voltage setting provides the soft "buttering" arc with best resistance to pop-outs pre- ferred for most welding. To get this characteristic, set the CURRENT RANGE SELECTOR to the lowest set- ting that still provides the current you need and set the FINE CURRENT ADJUSTMENT near maximum. For example: to obtain 175 amps and a soft arc, set the CURRENT RANGE SELECTOR to the 190 to 120 position and then adjust the FINE CURRENT ADJUST- MENT for 175 amps.

When a forceful "digging" arc is required, usually for vertical and overhead welding, use a higher CURRENT RANGE SELECTOR setting and lower open circuit voltage. For example: to obtain 175 amps and a force- ful arc, set the CURRENT RANGE SELECTOR to 240- 160 position and the FINE CURRENT ADJUSTMENT setting to get 175 amps.

Some arc instability may be experienced with EXX10 electrodes when trying to operate with long arc tech- niques at settings at the lower end of the open circuit voltage range.

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FIGURE B.2 – CURRENT CONTROLS

	CURRENT RANGE	FINE CURRENT
	SELECTION	ADJUSTMENT	50
190-120		60	50
240-160	130-80	70	40
220	90	80	30
MAX.	MIN.
		90	20
		100	10	FINE CURRENT
				FINE CURRENT
IDLER	IGNITION PRESSURE	START	CHOKE	ADJUSTMENT
	OIL	START

CURRENT	REMOTE
	CONTROL
RANGE
SELECTOR

CLASSIC I

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Contents Classic I TM California Proposition 65 Warnings SafetyElectric Shock can kill Iii Welding Sparks can cause fire or explosionSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications Classic InstallationLocation and Ventilation Safety PrecautionsStoring PRE-OPERATION Engine Service Trailers Cooling SystemMuffler Exhaust Spark ArresterFigure A.1 Ground Stud Location Machine GroundingCable size for combined length Auxiliary Power Receptacle PLUGS, and HAND-HELD EquipmentElectrical Output Connections Welding Cable ConnectionsClassic Table of Contents Operation Section Operation Safety InstructionsOperating Instructions Generator Operational Features and ControlsRecommended Applications WelderWELDER/GENERATOR Controls Controls and SettingsFigure B.2 Current Controls Control of Welding CurrentReturn Section TOC Gasoline Engine ControlsBefore Starting the Engine Engine OperationStarting the Engine Cold Weather Starting Stopping the EngineBREAK-IN Period After you finish welding Welding OperationTable B.1 Range Settings for Wire SIZE/SPEED Auxiliary PowerTable of Contents Accessories Semiautomatic Welding Accessories OPTIONS/ACCESSORIESClassic I Across the ARC with Connection of Lincoln Electric Wire FeedersWire Feed Module see Figure C.1 Connection of the LN-25 toClassic Table of Contents Maintenance Engine Maintenance Safety Precautions Routine and Periodic MaintenanceFigure D.1 OIL Drain and Refill MAX MIN Figure D.2A Engine Coolant Drain Plug Tool. See Figure D.4 After cleaning or when installing a new spark plugGap Specifications 0.032 inch .8 mm Set the terminal gap with a feeler gauge or gappingClassic I charging system is Negative Battery MaintenanceReturn to Section Return to Section TOC WELDER/GENERATOR MaintenanceIdler Maintenance Figure D.5 Major Component Locations Classic Table of Contents Theory of Operation Section Theory of Operation BATTERY, STARTER, Engine Alternator and OIL Switch CircuitGeneral Description Excitation Flashing ENGINE, Main Generator Armature and Frame and DC ExciterMain SHUNT, Interpole and Series Coils Current Range Selector Fine Current AdjustmentEngine Idler Circuit DC Generator Machines Return to Section TOC Table of Contents Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & RepairPC Board can be damaged by static electricity PC Board Troubleshooting ProceduresObserve Safety Guidelines Troubleshooting GuideDetailed in the beginning of this manual Shunt Field Winding Test Main Generator Throttle Adjustment Test Output Problems Function Problems Troubleshooting & Repair Engine Problems Welding Problems Test Description DC Exciter TestMaterials Needed DC Exciter Test Test ProcedureFigure F.2 Exciter Cover Removal Shunt Coil and Series Coil Resistance Tests Small Flex Lead SolidIdler Solenoid Test Troubleshooting & Repair Main Generator Shunt Field Winding Test Main Generator Shunt Field Winding Test Figure F.6 Plug P10 PIN Assignments TAB Engine Throttle Adjustment Test Strobe Tach Method Engine Throttle Adjustment TestAdjust High Idle Engine Throttle Adjustment TestAdjust Low Idle Description Flashing the FieldsFlashing the Fields ProcedureFigure F.11 Brush HOLDER/BATTERY Jumper Connections Normal Open Circuit Voltage Waveform 115VDC Supply Scope SettingsHigh Idle no Load Fine Current Control Rheostat AT Maximum Normal Open Circuit DC Weld Voltage Waveform Typical DC Weld Voltage Waveform Machine Loaded Selector Switch AT MaximumDC Exciter Armature and Field Coils Removal and Replacement Reassembly DC Exciter Armature Removal ProcedureDC Exciter Armature and Field Coils Perform the DC Exciter Armature Removal Procedure Field Coils Removal ProcedureMain Generator Frame Removal and Replacement Replacement Bolt / NUT Main Generator Frame RemovalPerform the DC Exciter Armature Removal Lead Figure F.16 Selector Switch Lead Removal TerminalFigure F.18 Choke Control Cable Removal Loosen Here Main Generator Frame Removal Figure F.20 Front Panel Fastener Removal Troubleshooting & Repair Remove Mounting NUTS, Washers Bolts FeetPerform the DC Exciter Armature Reassembly Procedure Main Generator Armature Removal and Replacement Armature is now free to be removed from the engine Main Generator Armature RemovalWelder DC Output DC Auxiliary Power Receptacle OutputRetest After Repair Engine OutputElectrical Diagrams Section Wiring Diagram Classic Electrical DiagramsWiring Diagram Wire Feed Module Wire Feed Module Wiring Diagram16990 M Schematic Idler PC BoardIdler PC Board Assembly Idler PC Board