Troubleshooting & repair, Scr removal and replacement (continued) – Lincoln Electric IDEALARC R3R-500 User Manual
Page 85
TROUBLESHOOTING & REPAIR
F-51
F-51
IDEALARC R3R
CLAMPING PROCEDURE
FOR 1/4-28 CAP SCREWS
NOTE: This procedure can only be used with
1/4-28 cap screws.
Do not use cap screws with any other type
thread or new SCR will be damaged.
Do not over tighten cap screws. The leaf spring
will apply the required clamping force to the
SCR.
1. Do not turn the nuts. While holding the nuts
stationary, turn the cap screws only with the
following procedure.
2. Tighten first cap screw 1/4 turn.
3. Tighten second cap screw 1/2 turn.
4. Tighten first cap screw 1/2 turn.
5. Tighten second cap screw 1/2 turn.
6. Tighten first cap screw 1/2 turn.
7. Tighten second cap screw 1/4 turn. STOP.
8. Assembly now has the proper clamping
force.
9. Perform the Active SCR Test.
AFTER REPLACING THE SCRs
Follow the steps in the SCR/Diode Rectifier
Removal and Replacement procedure to
reassemble the machine.
CLAMPING PROCEDURE
FOR 1/4-20 CAP SCREWS
NOTE: This procedure can only be used with
1/4-20 cap screws.
Do not use cap screws with any other type
thread or new SCR will be damaged.
Do not over tighten cap screws. The leaf spring
will apply the required clamping force to the
SCR.
1. Do not turn the nuts. While holding the nuts
stationary, turn the cap screws only with the
following procedure.
2. Tighten first cap screw 1/4 turn.
3. Tighten second cap screw 1/2 turn.
4. Tighten first cap screw 1/2 turn.
5. Tighten second cap screw 1/4 turn.
6. Tighten first cap screw 1/8 turn.
7. Tighten second cap screw 1/8 turn. STOP.
8. Assembly now has the proper clamping
force.
9. Perform the Active SCR Test.
SCR REMOVAL AND REPLACEMENT (continued)