ESAB Removing and Replacing Capacitor Bank Assembly in the Migmaster 251 Troubleshooting instruction

Brand: ESAB

Model: Removing and Replacing Capacitor Bank Assembly in the Migmaster 251

Type: Troubleshooting instruction

Replacing the capacitor bank assembly is a difficult

and critical procedure. This procedure should only be

undertaken by a skilled technician with the proper tools.

To install kit, proceed as follows:

1. Using the 3/8 wrench remove the four screws re-

taining the hinged cover.

2. Remove the hinged cover.

3. Using the 3/8 wrench remove the ten screws re-

taining the large side panel.

4. Remove the side panel.

5. Using the 3/8 wrench or the #3 Robertson screw-

driver remove the screw attaching the rear of the

bus-bar to the plastic mounting bracket.

6. Using the 7/16 wrench loosen the locking nuts

holding the heatsink-capacitor assembly to the

plastic mounting bracket.

7. Using the 9/16 wrenches loosen the nuts and bolts

at the rear of the output stud and the top of the

flexible shunt.

8. The heatsink may have sharp edges that can dam-

age wiring insulation, ensure the wires in the vicin-

ity of the heatsink are protected.

9. While supporting the weight of the capacitor as-

sembly and heatsink, remove the four loose bolted

connections.

10. Using a 7/16 wrench remove the nut attaching the

heatsink to the capacitor bus bar.

11. Carefully remove the capacitor assembly from the

machine.

12. Apply electrical joint compound to the areas around

the three bolt holes of the capacitor bus-bars.

13. Insert the capacitor bus-bar over the bolt in the top

of the heatsink.

14. Align the rear edge of the bus-bar with the heatsink

and attach with a regular nut.

15. Ensure that the bolted connection from the heatsink

to the capacitor bus-bar is tight. This is a high

current electrical connection.

16. Replace the flat washer over the nut.

17. Supporting the weight of the capacitor bank, insert

the bolts from the heatsink into the holes in the

plastic bracket.

18. Install flat washers and locking nuts over the bolts

from the heatsink. Do not fully tighten.

19. Align the top of the bus bar with the back of the

output stud, insert the 3/8 bolt through the output

stud the bus-bar and the copper tab.

20. Assemble the flat washer, lock washer, and 3/8

nut to the bolt.

21. Align the bottom of the bus bar with the inductor

lead and flexible shunt, insert the 3/8 bolt through

the output stud the bus-bar and the copper tab.

22. Assemble the flat washer, lock washer, and 3/8

nut to the bolt.

The Capacitor replacement kit includes:

• 1 Capacitor bank assembly

• 2 1/4-20 locking nuts

• 2 1/4-20 nuts

• 7 1/4 flat washer

• 2 1/4-20 x 1 long screws

• 2 3/8-16 nut

• 4 3/8 flat washer

• 2 3/8 split lock washer

• 2 3/8-16 x 1 long screws

Tools required:

1. 1 3/8 wrench

2. 1 7/16 open ended wrenches

3. 2 9/16 open ended wrenches

4. 1 #3 Robertson screwdriver

5. Electrical joint compound #2

(Alcoa #2 EJC) - 73585980

Removing and Replacing Capacitor Bank Assembly

in the Migmaster 251

P/N 37493

INSTRUCTIONS for

F-15-479

August, 1998

Before installing this kit, make sure all primary input power to the

power source is disconnected and/or lock out procedures are in place.

23. Insert and tighten the 1/4-20 screw through the

plastic bracket to the capacitor bus-bar.

24. Tighten all bolted connections.

25. Insure proper clearances exist between conduc-

tors and nearby parts.

26. Insure proper clearances exist between primary

and secondary conductors.

27. Replace the side panel.

28. Using a 3/8 wrench install the ten side panel

mounting screws, do not fully tighten.

29. While supporting the hinged cover in place install

the four cover mounting screws.

30. Tighten the fourteen screws to retain the side and

top covers.

Fig. 1 - Capacitor Bank Assembly for Migmaster 251

F-15-479 8/98

Supplied

ESAB Removing and Replacing Capacitor Bank Assembly in the Migmaster 251 Troubleshooting instruction

ESAB Removing and Replacing Capacitor Bank Assembly in the Migmaster 251 Troubleshooting instruction

ESAB Removing and Replacing Capacitor Bank Assembly in the Migmaster 251 Troubleshooting instruction

Related papers

Other documents