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GEH-5304A
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G. Mechanical
Check the condition of air filters and replace filters if they are dirty. Check for unusual noises which were
not present when the unit was originally installed. Check all electrical connections for tightness. Clean out
any dirt from screens, louvers, etc. which would interfere with the flow of cooling air.
H. Shaft End Play
The CD2512AT-CD2813AT designs use a wavy washer (preload spring) to eliminate endplay.
I. Waterproof Machines
Waterproof machines require the use of sealing devices to exclude water from the bearings and from entering
openings in the magnet frame. When a waterproof machine has been disassembled, it will be necessary to
remove the old sealing compound from around the mating surfaces of the bearing brackets and magnet
frame, from underneath the field pole bolt heads and bearing cap to bearing bracket bolt heads, and from
around the conduit box adapter threads to the magnet frame. Reapply new sealant (use Titeseal T20-66,
light weight, GE Part No. 905A999AC009) to these areas and wipe excess sealant with a clean rag slightly
dampened with mineral spirits. Do not use silicone sealants. When accessories such as brakes and ta-
chometers are disassembled, it will be necessary to reseal at the accessory mounting face. Prior to reassem-
bly, inspect for damage at the gaskets around enclosure covers and at the shaft rubbing seals located in the
bearing caps.
J. Lubrication of Flexible Couplings
Flexible couplings are normally lubricated with a semi-fluid grease or an oil. The coupling manufacturers’
instructions should be followed in choosing a lubricant and setting relubrication intervals. GE ball bearing
grease D6A2C5 is a suitable lubricant for flexible couplings in most applications.
Flexible couplings which join a small machine to a large machine may have two different size coupling
halves joined by an adapter plate. Couplings of this type have a separate lubricant supply for each half.
Therefore, both halves must be lubricated separately.
K. Insulation
Eliminate sources of contamination and moisture for maximum insulation life.
Air filters for blowers, air piped from cleaner locations, shielding from water
leads or spray, proper use of space heaters during downtime, etc., will all help
to prolong insulation life.
Contamination includes excessive moisture, oily vapors, conducting and non-conducting dust, chips and
chemical fumes. Contamination is best avoided by proper enclosure and ventilation. Filters, ventilation
from a remote clean air source, unit coolers and a totally enclosed construction are all possible means of
protecting DC machines in adverse environments. Space heaters protect against moisture damage by main-
taining the machine above dew-point during storage or when idle. Space heaters should be arranged so that
they are automatically energized whenever power is removed from the motor. Space heaters do not supply
enough heat for drying out windings which have been water-soaked.
Mechanical factors include shock, vibration, overspeed, etc. Maintaining machines in good mechanical re-
pair, including isolation from excessive external shock and maintenance of smooth running conditions, will
contribute to long insulation life.
The insulation system in these machines is capable of withstanding some short time periods of operation at
temperatures higher than than used for the basis of machine rating. Prolonged or excessively high tempera-
ture will cause the insulation to become brittle and crack, leading to premature failure. Application data is
available from GE Industrial Systems for any particular machine giving suggested maximum loads for vari-
ous operating conditions. Operation within these maximum loads will limit the temperature to suitable val-