Table of Contents
Advertisement
Troubleshooting
Your motor service and any troubleshooting must be handled by qualified persons who have proper tools and
equipment.
Problem
Motor fails to start
Motor stalls
Motor runs and then
dies down
Motor does not come
up to speed
Motor takes too long to
accelerate
Wrong rotation
Motor overheats while
running under load
10
Vane Axial Fans
Cause
Blown fuses
Overload trips
Improper power supply
Improper line connections
Open circuit in winding or
control switch
Mechanical failure
Short circuited stator
Poor stator coil connection
Impeller defective
Motor may be overloaded
One phase may be open
Wrong application
Overload motor
Low motor voltage
Open circuit
Power failure
Not applied properly
Voltage too low at motor
terminals because of line
drop
Starting load too high
Broken impeller blade(s) or
loose impeller
Open primary circuit
Excess loading
Poor circuit
Defective motor
Applied voltage too low
Wrong sequence of phases
Overloaded
Frame or bracket vents may
be clogged with dirt and
prevent proper ventilation of
motor
Motor may have one phase
open
Grounded coil
Unbalanced terminal voltage
Corrective Action
Replace fuses with proper type and rating.
Check and reset overload in starter.
Check to see that power supplied agrees with motor
nameplate and load factor.
Check connections with diagram supplied with motor.
Indicated by humming sound when switch is closed.
Check for loose wiring connections. Also verify all control
contacts are closing.
Check to see if motor and drive turn freely. Check bearings
and lubrication.
Indicated by blown fuses. Motor must be rewound.
Remove end bells, locate with test lamp.
Look for broken bars or end rings.
Reduce load.
Check lines for open phase.
Change type or size. Consult manufacturer.
Reduce load.
See that nameplate voltage is maintained. Check
connection.
Fuses blown, check overload relay, stator and push
buttons.
Check for loose connections to line, to fuses, and to
control.
Consult supplier for proper type.
Use higher voltage on transformer terminals or reduce
load. Check connections. Check conductors for proper
size.
Check what load motor is supposed to carry at start.
Look for cracks near the rings. A new impeller may be
required as repairs are usually temporary.
Locate fault with testing device and repair.
Reduce load.
Check for high resistance.
Replace with new motor.
Get power company to increase power tap.
Reverse connections at motor or at switchboard.
Reduce load.
Open vent holes and check for a continuous stream of air
from the motor.
Check to make sure that all leads are well connected.
Locate and repair.
Check for faulty leads, connections and transformers.
®
Advertisement
Table of Contents
