Circuit Protection

B-4

OPERATION

Return to Section TOC

Return to Master TOC

A manual reset circuit breaker protects the AC supply line and the wire feeder from overloads, usually caused by excessive wire drag or other wire feed problems. To reset the circuit breaker, raise the cover of the wire drive compartment and push the white button on the side of the control box above the drive rolls. If the circuit breaker trips again, refer to the Troubleshooting Section.

The LN-7 GMA also includes a Ground Lead Protector (GLP) circuit and fuse in the 2-4 contactor circuit. See the Theory of Operation Section for a description of these circuits.

AVOIDING GROUND LEAD PROTECTOR (GLP) ACTIVATION

DO NOT allow the electrode to contact the case of the wire feeder or the uninsulated part of the wire reel stand when the gun trigger is activated.

Be sure that all work lead connections to the work make tight metal-to-metal contact.

DO NOT allow excess input cable or work cable to be placed closer than three feet from the wire feeder.

DO NOT coil excess input cable assembly or use a coiled assembly as shipped from the factory. Instead, loop the excess cable length back and forth in three to six foot straight lengths. Coiling the input cable results in a transformer action between the electrode conductor cable and the ground lead in the multiconductor control cable. This transformer action can cause a current to flow in the ground lead which will falsely activate the GLP circuit.

To reset the GLP circuit, press the red button above the drive rolls and to the left of the circuit breaker.

DRIVE ROLL INSTALLATION

CHANGING DRIVE ROLLS FOR TWO- ROLL WIRE FEEDERS:

To change drive rolls on a two-roll wire feeder, refer to Figure B.2 and perform the following steps:

1.Rotate the latch knob on the quick release arm.

2.Remove the hex head screw and clamping collar. Remove the drive roll from the shaft. On new machines, remove the tape and the drive key.

3.The new roll to be installed is stamped for the size to be fed. An “A” after the size indicates aluminum wire. Remove the rolls from the kit and wipe them clean. Wipe the output shaft and locating shoulder clean.

4.Use the drive key, clamping collar, and hex head screw to install the roll on the output shaft. Certain size drive rolls consist of two roll halves, and may contain a spacer. If the drive roll you are installing contains a spacer, the spacer fits between the two halves of the drive roll. Tighten the hex head screw.

5.Back out the guide tube clamping screws. Remove the old guide tubes, if installed.

6.Insert the outgoing guide tube (the one with the plastic insert) into the front hole. If the guide tube has a non-symmetrical chisel end, the larger radius must face the drive roll. See Figure B.2. Push the guide tube back as far as it will go and tighten the clamping screw. Insert the incoming guide tube as far back as it will go and tighten the clamping screw. The clamping screws are dog points. When the guide tubes are properly installed these dog points will lock into the annular grooves in each of the guide tubes.

7.Set the idle roll pressure as detailed in the Idle Roll Pressure Setting procedure detailed later in this section.

Lincoln Electric SVM 106-A service manual Circuit Protection, Drive Roll Installation

Models: SVM 106-A

OPERATION