Miller Electric CST 250 VRD manual Stick Start Procedure − Scratch Start Technique, Lift-Arc Start

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4-3. Stick Start Procedure − Scratch Start Technique

1

2

3

With Stick selected, start arc as follows:

1Electrode

2Workpiece

3Arc

Drag electrode across workpiece like striking a match; lift electrode slightly after touching work. If arc goes out electrode was lifted to high. If electrode sticks to workpiece, use a quick twist to free it.

Normal open-circuit voltage is not present before electrode touches workpiece; only a low sensing voltage is present between electrode and workpiece. This allows electrode to touch workpiece without overheating, sticking, or getting contaminated.

4-4. Lift-Arc™Start Procedure

Lift-Arc Start Method

1 2

	“Touch”	1 − 2
	“Touch”	Seconds
		Seconds

Do NOT Strike Like A Match!

Lift-Arc Start

With Lift-Arct selected, start arc as follows:

1TIG Electrode

2Workpiece

Turn gas on. Touch tungsten electrode to workpiece at weld start point. Hold electrode to workpiece for 1-2 seconds, and slowly lift electrode. Arc is formed when electrode is lifted.

Normal open-circuit voltage is not present before tungsten electrode touches workpiece; only a low sensing voltage is present between electrode and workpiece. The solid-state output contactor does not energize until after electrode is touching workpiece. This allows electrode to touch workpiece without overheating, sticking, or getting contaminated.

Application:

Lift-Arc is used for the DCEN GTAW process when HF Start method is not permitted, or to replace the scratch method.

OM-220 812 Page 21

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Contents Processes OM-220 812BDescription From Miller to You Table of Contents Page Marks a special safety message Symbol UsageArc Welding Hazards Electric Shock can killWelding can cause fire or explosion ARC Rays can burn eyes and skinFlying Metal can injure eyes Buildup of GAS can injure or killCalifornia Proposition 65 Warnings EMF Information Principal Safety StandardsAbout Pacemakers − Consignes DE Sécurité − À Lire Avant Utilisation Signification des symbolesLES Décharges Électriques peuvent être mortelles LES Fumées ET LES GAZ peuvent être dangereuxLES Particules Projetées peu- vent blesser les yeux LE Soudage peut causer un incen- die ou une explosionLES Pièces Chaudes peuvent cau- ser des brûlures graves LE Bruit peut affecter l’ouïeLA Chute DE L’APPAREIL peut blesser Risque D’INCENDIE OU D’EXPLO’EMPLOI Excessif peut Faire LES Pièces Mobiles peuvent cau- ser des blessuresInformation sur les champs électromagnétiques Principales normes de sécuritéConsignes relatives aux stimulateurs cardiaques Specifications − InstallationDuty Cycle And Overheating DC Amps Stick Smaw Volt-Ampere CurvesTIG Gtaw Volt-Ampere Curve Selecting a Location Dimensions And WeightLocation And Airflow 150 ft 200 ft 250 ft Weld Output Terminals And Selecting Cable Sizes350 ft 400 ft 45 m 60 m 70 m 90 m 105 m 120 m Terminals AmperesPositive + Weld Output Terminal 50/60 Hz Single-Phase 50/60 Hz Three-Phase Electrical Service GuideStick Dcep Direct Current Electrode Positive Connections Input VoltageSelecting 220 Volts AC Single/Three Phase Input Voltage Relinking Board Connection For 400 440 VAC Input Power Selecting 400 440 Volts AC Three Phase Input Voltage For three-phase operation Connecting Input Power For single-phase operation = GND/PEControls − OperationLift-ArctTIG Normal Process Select ControlLift-ArcStart Procedure Stick Start Procedure − Scratch Start TechniqueLift-Arc Start ApplicationRemote 14 Receptacle Information Amp Adjust ControlFan-On-Demand Rack MountingRoutine Maintenance − Maintenance and TroubleshootingBlowing Out Inside Of Unit MonthsTrouble Possible Causes Remedy TroubleshootingUse proper size and type of weld cable see Section Circuit Diagram − Electrical Diagrams− Selecting and Preparing Tungsten Electrode Safety Information About TungstenSelecting Tungsten Electrode Tungsten Electrode OM-220 812 Main Assembly − Parts ListCAPACITOR,ELCTLT 2400 UF 500 VDC can 2.5 DIA Panel, Front w/Components Panel, Rear w/Components Magnetics Subassembly Heat Sink Assembly, Output Diode Base Assembly Heat Sink Assembly, Input Page Support ServiceMiller Electric Mfg. Co Owner’s Record