Lincoln Electric IM467-B manual Hand and Foot Amptrol Operation

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B-12

B-12

OPERATION

HAND AND FOOT AMPTROL OPERATION

Both the Hand and Foot Amptrol (optional kits K870 or K963) work in a similar manner. They are meant to be used for remote current control when Remote Current control is selected. The TIG 2-Step mode must be selected when using an Amptrol for remote current control. As explained below, Amptrols can also be used as arc start switches if Local Current control is selected.

For simplicity, the following explanation will refer only to “Amptrols,” meaning both Foot and Hand models. The term “minimum” refers to a Foot pedal in the “up” position, as it would be with no foot pressure, or a Hand Amptrol in the relaxed position, with no thumb pressure. “Maximum” refers to a fully depressed Foot Amptrol, or a fully extended Hand Amptrol.

The Amptrol is capable of controlling the output cur- rent from 2 amps to whatever current is preset on the ammeter. For example, if the ammeter is preset for 200 amps and the Current Control switch is in the Remote position, the Amptrol, when depressed just past its minimum position, will cause the Square Wave TIG 355 to weld at 2 amps. At the Amptrol’s maximum position, the output would be near 200 amps. See Figure B.4.

CAUTION

Since the full output of the current setting is available when the Amptrol is fully depressed, care must be taken not to set a current which will exceed the current carrying capacity of the tungsten. When in doubt, use a lower current setting first, then increase.

It is important to note that, for many applications, the tungsten will not start an arc at only 2 amps. To start an arc reliably, it is important to depress the Amptrol far enough so that the machine output current is near the tungsten operating range. (See Table B.2 for rec- ommended tungsten currents.) In the example above, a 3/32” (2.4 mm) tungsten may be used on DC- to weld near 200 amps. To start the weld, the operator may have to depress the Amptrol approximately 1/4 of the way down, or to nearly 70 amps, in order to start the arc. Merely depressing the Amptrol to its 2 amp minimum position will not start the arc.

A similar situation occurs when the Start controls are used. For example, a 3/32” (2.4 mm) tungsten is again used for welding DC- up to 200 amps (preset on the ammeter). A Start current of 50 amps is set on the Start Level control. When you depress the Amptrol, the start circuitry sets the output current to 50 amps. If the Amptrol is kept near the minimum position, at the end of the start period the output current will drop to 2 amps, causing the arc to go out in most cases. Depress the Amptrol at least 1/4 of the way down, or to around 70 amps, so that the tungsten remains lit when the start period ends.

The same holds true for a “hot” start, or one in which the Start current is set to a current higher than the cur- rent preset on the ammeter. Again, at the end of the start period, the Amptrol must be depressed far enough so that the machine output will be high enough to keep the arc lit.

The best technique when using the start controls and an Amptrol is to press the Amptrol to maximum at the beginning of the weld, wait until the end of the start period, and then back off on the amptrol only if the current is too high.

If the Current Control switch is set to the Local posi- tion, an Amptrol can be used as an arc start switch. Depressing the amptrol just past minimum will cause the Amptrol’s built-in arc start switch to close, and backing off completely causes the built-in start switch to open. The Amptrol will have no effect on the weld- ing current when used as an arc start switch. See Figure B.5.

SQUARE WAVE TIG 355

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Contents Square Wave TIG Safety Electric Shock can kill Cylinder may explode if damaged Précautions DE Sûreté Thank You Table of Contents P196 Series Section CSection D Section ETechnical Specifications Square Wave TIG InstallationSafety Precautions Select Suitable LocationHigh Frequency Interference Protection Electric Shock can kill Input ConnectionsGround Connection Input Supply ConnectionFigure A.2 Input Supply Connections Reconnect ProcedureVolt/Freq AC Output AWG Copper Cond Table A.1 Recommended Input Wire and Fuse SizesTable A.2 Recommended Input Wire and Fuse Sizes Volt/Freq Nameplate AWG Copper Cond100 ft 30 m 30 to 61 m 61 to 76 m Output ConnectionsTIG Torch Connection Lengths up to 100 to 200 ft 200 to 250 ftStick Electrode Cable Connection Operating Instructions Safety InstructionsRecommended Processes Operational Features and ControlsDesign Features and Advantages General DescriptionLimitations Welding CapabilityUpper Case Front Controls Controls and SettingsUpper Case Front Control Panel Mode SwitchSTEP/4-STEP Switch High Frequency SwitchAuto Balance LED VOLTS/AMPS SwitchPeak Current Control AC Wave BalanceSpot Controls Pulse ControlsStart Controls Crater Fill Controls Figure B.2 Status Indicator Light Sequence Square Wave TIGOperation Figure B.3 Lower Case Frontcontrols Square Wave TIG Lower Case Front ControlsOperation Hand and Foot Amptrol Operation Operation TIG Welding Guidelines Welding OperationInitial START-UP Stick WeldingTable B.1 Specific Effects of Controls Illustrated in the 2-Step Mode for clarityOFF Crater Fill Switch onSpot Switch on Start Switch onPulse Switch on Crater Fill Switch on Spot Switch OFFDcen Dcep + Unbalanced Wave Balanced Wave Table B.2 Typical Current RANGES1 for Tungsten ELECTRODES2Polarity Switch TIG Welding Sequence Operation 2-STEP ModeTIG Welding Sequence Operation 4-STEP Mode Table B.3 Recommended Settings for TIG WeldingAuxiliary Power Overload ProtectionALL Machines OPTIONS/ACCESSORIES AccessoriesInput Power Factor Capacitor Discharge Procedure MaintenanceRoutine and Periodic Maintenance Figure D.2 General Component Locations General Machine Trouble Troubleshooting GuideSymptom Cause and Remedy Troubleshooting Guide Stick WeldingTroubleshooting Guide TIG Welding TIG Welding Lower Panel Controls K870 Foot Amptrol or K963 Hand Amptrol AccessoriesDiagrams Dimension Print Square Wave TIG355 Equipment MANUFACTURER’S Certification Equipment Installation CertificationPage Precaucion Aviso DE