Lincoln Electric LN-25 Service Manual page 31

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Proper positioning of this module is critical to proper
operation of the LN-25™ wire feed speed control. If
the device is not screwed in far enough, the LN-25™
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
re moved or replaced, proper mounting technique is as
follows:
1. Be sure all power to the LN-25™ is shut off at the
power source.
2. Check that the module mounting plate is screwed
securely to the side of the gearbox. Refer to Drive
Motor and Gearbox Replacement Procedure
and access to the Hall Effect Module in the
Troubleshooting and Repair Section.
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
lock nut without rotating the module position. Do
not over tighten lock nut.
CALIBRATION OF LN-25™ WIRE
SPEED DIAL
Calibration of the LN-25™ 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 LO range calibrated dial.
2. Set DIAL RANGE switch to LO and 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.
All manuals and user guides at all-guides.com
MAINTENANCE
turn, then snug the module
Electrode will be electrically "hot". Do not allow fed
wire to contact any metal common with welding work.
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-25™
WARNING
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