Lincoln Electric IM924 manual Pulse Welding, Figure A.6 Current Wave Form Pulse

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B-8	OPERATION	B-8

PULSE WELDING

Pulse welding procedures are set by controlling an overall "arc length" variable. When pulse welding, the arc voltage is highly dependent upon the waveform. The peak current, back ground current, rise time, fall time and pulse frequency all affect the voltage. The exact voltage for a given wire feed speed can only be predicted when all the pulsing waveform parameters are known. Using a preset voltage becomes impracti- cal, and instead the arc length is set by adjusting "trim".

Trim adjusts the arc length and ranges from 0.50 to 1.50, with a nominal value of 1.00. Trim values greater than 1.00 increase the arc length, while values less than 1.00 decrease the arc length.

Most pulse welding programs are synergic. As the wire feed speed is adjusted, the Power Wave will automati- cally recalculate the waveform parameters to maintain similar arc properties.

The Power Wave utilizes "adaptive control" to com- pensate for changes in electrical stick-out while weld- ing. (Electrical stick-out is the distance from the contact tip to the work piece.) The Power Wave waveforms are optimized for a 0.75" (19mm) stick-out. The adaptive behavior supports a range of stickouts from 0.50" (13mm) to 1.25" (32mm). At very low or high wire feed speeds, the adaptive range may be less due to reach- ing physical limitations of the welding process.

Arc Control, often referred to as wave control, in pulse programs usually adjusts the focus or shape of the arc. Wave control values greater than 0.0 increase the pulse frequency while decreasing the background cur- rent, resulting in a tight, stiff arc best for high speed sheet metal welding. Wave control values less than 0.0 decrease the pulse frequency while increasing the background current, for a soft arc good for out-of-posi- tion welding.

(See Figure A.6)

FIGURE A.6

CURRENT WAVE FORM (PULSE)

Current

Wave Control -10.0

Wave Control 0.0

Wave Control +10.0

Time

POWER WAVE 455M/STT (CE)

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Contents Power Wave 455M/STT Safety California Proposition 65 WarningsElectric Shock can kill Welding and Cutting Sparks can Cause fire or explosion IiiPrécautions DE Sûreté Sûreté Pour Soudage a L’ArcSafety Safety Thank You Table of Contents Table of Contents Installation Technical Specifications Power Wave 455M/STT CE K2203-4Machine Grounding High Frequency ProtectionLifting StackingInput Fuse and Supply Wire Considerations Input ConnectionElectrode and Work Cable Connections Table A.1Voltage Sensing Negative Electrode PolarityCable INDUCTANCE, and ITS Effects on Pulse Welding System Description Table A.2Work Voltage Sensing Electrode Voltage SensingConfiguring the System Single Head FeederSingle Head Boom Feeder UP to 4 Feeders AllowedDual Head Boom Feeder using two single heads Control Cable Specifications Welding with Multiple Power WavesTWO Power Waves Installation Receptacle Specifications DIP Switch Settings and LocationsControl Board DIP Switch Water Flow SensorSafety Precautions OperationPower Wave 455M/STT CE Definition of Welding Terms General Description Recommended Processes and EquipmentRecommended Equipment Required EquipmentCase Front Controls Power Wave 455M/STT CECase Front Layout Nominal Procedures Fringe ProceduresWelding Adjustments Making a WeldConstant Voltage Welding Welding ModeARC Control Pulse Welding Figure A.6 Current Wave Form PulseSTT Welding Figure A.7Accessories Factory InstalledField Installed Optional EquipmentMaintenance Routine MaintenanceTroubleshooting HOW to USE Troubleshooting GuideUsing the Status LED to Troubleshoot System Problems Error Codes for the Powerwave Error Code # Description IndicationAuthorized Field Service Facility Contact your local LincolnIf the Thermal LED is also lit, see Exceeding the 325 amp limit on WFS Power Wave 455M/STT CE Wiring Diagram Connection Diagram Connection Diagram Semi-automatic Simple SystemWire Feeder Work Sense Power Wave 455/STTDiagrams Power Wave 455M/STTPrecaucion Aviso DE