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Likely
Cause:
F .
Motor miswired at terminal box.
G.
Uneven, weak or loose mounting support.
H.
Motor bearings defective.
I.
Motor out of balance.
Bearings repeatedly fail
Load to motor may be excessive or
A.
unbalanced.
B.
Bearings contaminated.
Incorrect grease or bearings for
C.
ambient extremes.
D.
VFD bearing damage.
Motor at start up, makes a loud rubbing, grinding, or squealing noise
Contact between rotating and stationary
A.
components.
Start capacitors repeatedly fail
A.
The motor acceleration time is too long.
B.
Motor is being started too frequently.
C.
Motor voltage low.
D.
Defective start switch inside motor.
Run capacitor fails
A.
High ambient temperature.
B.
Input voltage exceeds limit.
Power surge to motor (caused by
C.
lightning strike or other high transient
voltage).
14
©2019, 2020 Regal Beloit Corporation, All Rights Reserved. MCIM2022E • Form# SB0250E
Corrective Action:
Match motor lead wiring to nameplate connection diagram.
Shim, strengthen or tighten where required.
Test motor by itself.
• If bearings are bad, you will hear noise or feel roughness. Roller bearings
are normally noisy when operated without load, limit roller bearing no load
run time to five minutes.
• If sleeve bearing, add oil per nameplate instructions. For motors with
regreasing provisions, add grease per relubricating instructions (see
section 7 .5).
• If noise persists contact warranty service.
1. Disconnect from load.
2. Set motor on rubber pads on solid floor.
3. Secure a ½ height key in shaft keyway and energize from balanced power
supply at rated voltage.
4. Record vibration levels and compare with appropriate standards.
If excessive vibration persists contact motor manufacturer.
1. If belt drive check system per section 4.3.2.
2. Other than belting, check loading on motor shaft. An unbalanced load will
also cause the bearings to fail.
3. Check runouts of mating components, such as a C-face and pump flange.
Motor enclosure not suitable for environment. Replace with correct
enclosure construction.
See Section 7 .3 (Grease types).
Ground brush, common mode filter, or insulated bearings must be added.
Contact motor manufacturer.
Belt squeal during across the line starting is normal:
1. CAUTION! Verify that supply voltage is within limits (see section 4.6).
2. Ensure that motor lead wiring matches nameplate connection diagram:
3. Isolate motor from load.
4. To locate point of contact turn motor shaft by hand.
5. If point of contact is not located contact motor service shop.
Motor may be too small for load. Record acceleration time. Start
capacitors may fail if acceleration time exceeds 3 seconds.
Excessive starting will damage motor capacitors. Contact motor
manufacturer if motor is started more than 20 times/hour or if acceleration
time exceeds 3 seconds.
CAUTION! Verify that voltage at the motor terminals is within limits (see
section 4.6).
Motor internal switch failure overheats start capacitor. Contact service
shop or motor manufacturer.
Verify that the ambient does not exceed motor's nameplate value.
CAUTION! Verify that voltage at the motor terminals is within limits (see
section 4.6).
If a common problem, install surge protector.
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