Ge GEH-5304A User Manual download pdf (Page 23)

GEH-5304A

a. Unfasten pigtail.

b. Release spring by pushing in slightly to disengage locking tab, then pull spring back.

c. Remove brush.

2. Brush Installation

The following procedure should be used to install brushes:

a. Place brush in holder with bevel towards spring. Brushes should move freely in holder.

b. Push spring into position until lock tab engages slot and locks.

c. Connect pigtail.

The presence of silicone in DC motors, particularly with totally enclosed con-

structions, will cause rapid brush wear. Sources of silicone include oils, RTV

compounds, hand creams, mold release agents, grease and some insulating

varnishes. These silicone substances must be avoided to ensure proper motor

performance.

Brushes should have their commutator contact surfaces curved to exactly fit the commutator surface.

This is accomplished by “sanding in” the brushes in each brushholder separately. Draw a sheet of

coarse non-metallic sandpaper under the brushes with the rough side toward the brush, while the

brushes are pressed firmly toward the commutator. Do not use emery cloth. When sanding brushes,

do not get carbon dust into the windings. The motor should be thoroughly blown out after sanding the

brushes. This can be accomplished by cleaning the dust from the commutator, brushholders and adja-

cent parts with a vacuum cleaner, air blast or other suitable means. After the rough sanding, the

brushes should be finely ground to fit using a brush seater. Rotate motor at around nameplate RPM.

Make sure there is no load on the machine (armature current is nil). Carefully and lightly rub the

brush seater across the entire commutator surface for 10 or 15 seconds. Repeat between each and

every set of brush studs. Reverse motor rotation and repeat. Stop motor and cut all power to the mo-

tor and check brush face. Continue seating until brush face is 85% seated. Again, the motor must be

thoroughly blown out after brush seating, the same as with sanding.

Avoid inhaling carbon and seater dust. GE Industrial Systems recommends

using a dust mask during sanding, seating and blowing or vacuuming.

High voltage and rotating parts can cause serious or fatal injury. The use of all

electric machinery, like all other utilization of concentrated power and rotating

equipment, can be hazardous. Installation, operation and maintenance of elec-

tric machinery should be performed by qualified personnel. Familiarization

with NEMA Safety Standards for Construction and Guide for Selection, Installa-

tion

and Use of Integral HP Motors and Generators , National Electrical Code and sound local prac-

tices is recommended.

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Ge GEH-5304A User Manual Page 23