GE GE752 manual Commutator Resurfacing, Installation, Brushholder Clearance Adjustment

GEK±91584D, Vertical Drilling Motor, Type GE752

3. Remove bolt, washer and brushholder clamp.	COMMUTATOR RESURFACING
Lift the brushholder out of the frame.
Installation	Prior to resurfacing, consider the following:

1.Position the brushholder in the frame with the brushholder studs resting in the clamp surfaces of the brushholder support.

2.Install bolt and washer. Tighten bolt but do not torque until the brushholder±to±commutator clearance has been established. Refer to Brush- holder Clearance Adjustment section for instruc- tions to adjust brushholder clearance.

3.After brushholder clearance has been set, con- nect the brushholder cable and remove protec- tive paper from commutator surface.

4.Check brushes to insure they exceed the mini- mum brush length dimension and are free of any damage. If they are long enough and are not damaged, they can be re±used. If not, replace with new brushes.

BRUSHHOLDER CLEARANCE

ADJUSTMENT

Refer to the DATA section for the brushholder±to± commutator clearance dimension and adjust brushhol- der as follows:

1.The brush surface diameter of the commutator must not be less than the minimum permissible diameter, listed in the DATA section, after resur- facing operations are completed.

2.The commutator can be resurfaced by sanding, stoning or grinding. Choose the method to be used based on the condition of the commutator.

NOTE: Outside power will be required to oper- ate the motor for the following commutator±re- surfacing procedure.

WARNING: For the safety of personnel during resurfacing operations, the following safety precautions must be adhered to:

1.A second person must be at the auxiliary power (welder) control station, ready to shut off power in case of an emergency during the grinding operation.

2.The grinding operator should wear goggles and a dust mask when resurfac- ing or blowing out the commutator.

3.To avoid electrical shock, do not touch any part of the machine interior during grinding operations.

1.Remove the brushes.

CAUTION: Do not allow the brushholder to touch, bump or rest on the commutator.

2.Insert a fiber gauge (equal in thickness to the clearance dimension) between the commutator and the brushholder. (Loosen brushholder first if below minimum allowable clearance.)

Do NOT use a metallic gauge.

3.Loosen the brushholder support bolt and move the brushholder against the fiber gauge so clea- rance±to±commutator is the same as the gauge thickness.

4.Torque bolt to 225±250 ft.±lb. and recheck the brushholder clearance gap.

Preparation For Operating Series Model Machines For Commutator Resurfacing

1.Break the coupling (if applicable) so the machine can be operated from a d±c welding set or other outside d±c power source.

2.Lift all the brushes except two of opposite polarity (adjacent brushholders) which are necessary to operate the motor.

3.Connect the machine to an outside source of controlled d±c power; such as a 3±5 kw, 100 vdc welding set which is capable of driving it at a speed of 900±1000 rpm.

4.Refer to Fig. 7 for diagram of connections to run a series machine from a welding set. Connect

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