Lincoln Electric IM812-A Adjusting Speed Sensor Module, Calibration of LN-35 Wire Speed Dial

D-2 MAINTENANCE D-2

ADJUSTING SPEED

SENSOR MODULE

The LN-35 Speed Sensor Module is a three lead Hall Effect switch device encased in an externally threaded housing which is screwed into a mounting plate on the motor side of the wire drive gearbox.

Proper positioning of this module is critical to proper operation of the LN-35 wire feed speed control. If the device is not screwed in far enough, the LN-35 motor speed could be unstable or run at full speed with no control. If screwed in too far, it will rub a moving part inside the gearbox.

The module is properly mounted to the gearbox as shipped from the factory. If the device is ever removed or replaced, proper mounting technique is as follows:

1.Be sure all power to the LN-35 is shut off at the power source.

2.Check that the module mounting plate is screwed securely to the side of the gearbox.

3.Gently screw the module into the mounting plate until it just touches and stops against the rotating part inside the gearbox.

4.Back the module out 1/2 turn, then snug the module lock nut without rotating the module position. Do not overtighten lock nut.

CALIBRATION OF LN-35 WIRE SPEED DIAL

Calibration of the LN-35 Wire Speed dial is achieved by proper mounting of the dial knob to the speed potentiometer shaft. Whenever the knob is removed, the dial is recalibrated as follows:

NOTE: Knob set screw does not seat on shaft flat.

1.Be sure the Wire Speed potentiometer mounting nut is securely tightened, then rotate the potentiometer shaft so its flat faces about to the 100 mark on the calibrated dial.

2.Set WIRE FEED MODE switch to CV position.

3.Press gun trigger to feed wire and measure the wire feed speed (IN/MIN) using a Portable Digital Wire Feed Speed Meter (Lincoln K283). Take at least two readings to assure repeat- able accuracy.

Feed Speed Meter (Lincoln K283). Take at least two readings to assure repeatable accuracy.

WARNING

Electrode will be electrically “hot”. Do not allow fed wire to contact any metal common with welding work.

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An alternate means to measure wire feed speed is as follows:

a. Cut wire off at the end of the gun tip.

b. Press trigger to feed wire for exactly 30 seconds.

c. Cut fed wire off at the end of the gun tip and accurately measure its length.

d. Multiply the measured length by 2 to obtain the wire speed (IN/MIN).

e. Repeat above steps to assure repeatable accu- racy.

4.Carefully slip speed knob onto potentiometer shaft so it points precisely to the wire speed measured in step 3, then secure the knob set screw without disturbing the position. Recheck by repeating step 3.

LN-35