What did the shop find - What did they do to fix it?

3 Phase Motor Diagnosis and Repair Reference

Motor History

Reason for Removal from Service

Mechanical Diagnosis
Bearing failed due to circulating currents
Bearing failure
Bearing inner race welded to the shaft
Bearing is brunelled
Bearing outer race welded in housing
Bearing overlubricated
Bearing spun on the shaft
Bearing underlubricated
Bent foot
Broken foot
Channeling of rotating bearing elements
Copper or aluminum spatter
Core iron failed core loss test
Cracked or open rotor bar(s)
End shield cracked
End shield hit windings
End shield pinched leads
Fan cracked
Fan loose
Fan missing or broken fins
Fan retainer clip groove worn
Fan retainer clip missing
Feet not flat (in the same plane)
Foot cracked
Internal fan hit windings
Irons got hot
Irons misaligned
Irons uneven
Leads blown in terminal box
Liquid migrated into shaft or opposite end bearing
Loose coils
Loose sticks
Loose wedges
Motor overspeed
Oil boiled out of shaft end grease
Retainer bolts loosened
Retainer scrubbed on the shaft
Rotor moved on the shaft
Rotor scrubbed on the irons, damaged laminations
Rotor spun on the shaft
Shaft discolored
Shaft is bent at the shoulder
Shaft is broken at the shoulder
Shaft is peened over
Shaft scrubbed
Shaft slinger or seal failed
Shaft stub worn
Shorting ring is open
Slot insulation failed
Snakes, mice, bees
Stator cracked
Stator irons delaminated
Stator irons moved
Water line in stator or end shields
Winding blown at the corner
Winding blown in slot
Worn bearing housing(s)
Worn shaft end or opposite shaft end bearing journal
Mechanical Repair
Assemble, test, paint
Balanced rotor
Bored fan hub
Brush plating repair
Chiseled and burned off
Coil cut-off and burn off
Cold stripped
Converted from F1 to F2 (or vice versa)
Converted to open bearings
Converted to sealed bearings
Converted to shielded bearings
Laminations repaired
Magnaflux rotor irons
Masked stator
Replace shaft
Rewound and pour varnished
Rewound two dips and bakes
Shaft seal(s) replaced
Shaft slinger replaced
Shaft weld repair
Siliconed terminal box
Sleeve repair
Spray weld repair
Stator rabbet(s) repaired
Step key fabricate
Stripped and data collected
Electrical Diagnosis
Air gap densities high
Back iron densities high
Blown connections
Blown leads at connections
Growled the rotor
Hipot test failed
Leads grounded - pinched in the end shield
Leads grounded in the terminal box
Megger windings
One coil in one group is burned out
One phase is burned
Phase to phase short
PI test failed
Post cleaning test failed
Shorted connections
Start around the clock
Surge test failed
Tie cord is brittle or crispy
Tie cord is broken
Tooth densities high
Winding blown at the corner
Winding blown in the slot
Winding chaffed against end shield
Winding coils reversed
Winding data is incorrect
Winding is grounded
Winding overvoltage failure
Winding single phased
Winding turn to turn short
Winding unevenly overheated
Wire behind the paper
Electrical Repair
Class F epoxy
Class F insulating spray
Connect, form and tie
Continuity phase method winding
Converted concentric to lap winding
Converted consequent pole to lap winding
DEVCON 5 minute epoxy windings
Form wedges
Lead sleeving
Leads or connections were tied
Leads replaced
Motor was connected for 3 leads
Motor was connected for 9 leads
Pull up leads, reconnect
Reconnect for different voltage
Rewound class H
Siliconed leads
Tied down leads
Tied on overloads
VPI windings
Weave winding
Winding cleaned and baked
Winding cleaned and re-insulated
Winding cleaned and varnished
Winding re-designed
Wound for a different frequency
Wound for a different speed
Wound for different (higher/lower) voltage


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