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PROBLEM
Motor will not start
Motor noisy
Excessive Bearing
Temperature
(anti−friction bearing)
Excessive Bearing
Temperature
(sleeve bearing)
Excessive Temperature
Oil Leak
(sleeve bearing units)
Oil Leak (Flood
Lubrication System)
Excessive Vibration
MN409
This Manual:http://www.manuallib.com/baldor/mn409-large-ac-motors-handbook.html
Table 3-6 Troubleshooting Guide
POSSIBLE CAUSE
Motor improperly connected
Incorrect Line Voltage
Overload relay tripped
Fuses blown or defective
Open circuit in stator or rotor
Short circuit in stator
Grounded Winding
Winding single phased
Loose mounting
Noisy bearing
Coupling halves loose
Vibration
Inadequate lubrication
Coupling misalignment
Inadequate internal clearance
Inadequate ventilation
Inadequate oil supply
Excessive end thrust
Contaminated oil
Tight clearance
Oil rings not functioning
Bearing material wiped
Rough shaft or corrosion
Bearing Misalignment
Coupling misalignment
Shaft current
Overload
Restricted ventilation
Electrical
Overfilled
Seals not secured properly
Pipe fittings loose
Bearing air pressure equalizer vent
passage clogged
Wrong sealing compound used on
bearing cap surface
To much oil flow in pressure lube
system
Air pressure unbalanced
Coupling misalignment
Coupling , Coupling key or Rotor
Unbalance
Foundation resonance structure
improperly designed
Worn bearing
Coupled equipment
CORRECTIVE ACTION
Check motor connection and control connections
Check nameplate for required voltage
Correct and reset
Replace fuses
Check for open circuit
Check for short circuit
Check for ground
If winding is single phased, unit will not start.
Stop unit and try to reset
Check and correct
Check and replace
Inspect alignment and tighten
Check alignment with driver connected
Check feet planarity
Correct balance of motor if necessary
Check key unbalance on coupling.
Add lubricant per nameplate instructions
Realign unit
Incorrect replacement bearing − consult factory
Clean filters, check to see if louvers are blocked
Refer to nameplate requirements and correct
Check for proper lubrication, oil level, leaks
Check alignment and coupling float
Drain and refill, change filters in flood lube system
Inspect for source of contamination
Check bearing bore and shaft O.D for proper clearance.
Check for damage, check roundness and for burrs − repair or
replace if necessary
Dress, scrape and refit.
Dress and polish shaft
Realign bearing or reseat bearing
Realign motor
Insulate bearing and isolate shaft from ground
Reduce load to nameplate rating or replace with larger unit
Check openings and duct work for obstructions and correct
Check for grounded or shorted coils and unbalanced voltages
between phases
Drain to proper level or adjust oiler elevation
Tighten
Tighten or replace worn threaded parts
Clear out passage
Use Permatex Aviation type No. 3 or other non−hardening gasket
sealer
Reduce flow to recommended level on nameplate
Clean venting pipes
Realign to operating condition
Rebalance
Make adjustments to foundation
Replace bearing if oversize
Check motor vibration uncoupled, if necessary rebalance
equipment
Maintenance & Troubleshooting 3-9
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