Lincoln Electric LN-25 SVM179-B Service Manual page 37

D-3
Wire Feed Speed Validation
(See Figure D.1)
Calibration of the LN-25™ PRO may be required when
the p.c. board, wire feed speed potentiometer or motor is
replaced or serviced. Calibration matches the scale on
the name plate to the actual wire feed speed.
Tools required:
• RPM meter
• Constant voltage DC welding power source (DC-400,
V-350, CV-400 or equivalent)
• 7/16" open end wrench
To verify if calibration is necessary:
1. Turn power OFF.
2. Set the wire feed speed per the table.
Model gearing Wire Feed Speed Acceptable Range
Normal Speed 400 in/min
Extra Torque 150 in/min
3. Remove the plastic cover from the lower portion of the
wire drive with a 7/16" wrench.
4. Connect the LN-25™ PRO to the constant voltage DC
welding power source. The work lead of the LN-25™
PRO must be connected to the work terminal of the
power source.
5. Turn power ON.
6. Measure the motor rpm when the COLD FEED button
is pressed.
7. Verify the rpm is within the acceptable range.
FIGURE D.1
MOTOR
SHAFT
COVER
MAINTENANCE
To change the wire feed speed calibration:
(See Figure D.2)
Tools required:
• 5/16" nut driver
• RPM meter
• Shorting plug. LE CO.part # S18250-982 - The short-
ing plug shorts pins 4 & 8 of connector J3 on the Control
P.C. Board. J3 is an 8 pin Molex connector.
1. Turn power OFF.
2. Remove the 4 screws holding the rear cover inside the
feeder and remove the cover.
3. Open the idle arm.
4. Set the wire feed speed per the table.
Model gearing Wire Feed Speed
Normal Speed
69 - 77 rpm Extra Torque
25 - 31 rpm
5. Connect the LN-25™ PRO to the constant voltage DC
welding power source. The work lead of the LN-25™
PRO must be connected to the work terminal of the
power source.
6. Turn power ON.
7. Insert the shorting plug into connector J3 on the Control
P.C. Board. The shorting plug shorts pins 4 & 8.
8. Remove the shorting plug.
9. Turn power OFF.
10. Replace the cover and secure with the screws.
LN-25™ PRO
400 in/min
150 in/min
FIGURE D.2
COVER
P.C. BOARD
D-3