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Supply voltage is too low or is severely unbalanced (one
,
phase is low or missing).
7,
Motor leads are miswired at conduit box.
,
Driven load exceeds motor capacity
?,
Load is jammed.
,
Fan guard is bent and making contact with fan
,
VFD with power factor capacitors installed
6,
VFD with motor neutral lead grounded
&,
VFD programmed incorrectly
-
1
Supply voltage has drooped or has become severely
,
unbalanced
7,
Motor is overloaded
,
Motor bearings are seized
?,
Load Is jammed.
,
VFD will not restart motor after tripping
,
Capacitor failure on single phase motor (if equipped)
8
,
Motor leads are not connected correctly
Supply voltage has drooped or become severely
7,
unbalanced.
,
Load exceeds motor capability
?,
Faulty start capacitor (Single Phase)
,
Mechanical Failure
- +
,
Incorrect wiring connection at motor
) -
,
Driven Load is excessive
7,
Ambient temperature too high
,
Motor cooling fins and/or vent openings blocked
?,
Insufficient Air Flow
1
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(1) Check power supply fuses (2) Match motor lead wiring to nameplate connection
diagram and supply voltage (3) Ensure that steady state supply voltage at motor
terminals is within limits (see section 3.4.1.3). Correct as needed (4) Obtain correct
motor to match actual supply voltage.
(1) Verify that motor & load turn freely (2) Disconnect motor from load & ensure
motor turns freely. Note: Roller bearings make noise when motor is uncoupled and
shaft is rotated (3) Verify that motor starts when disconnected from load (4)
Remove excessive / binding load if present.
Replace fan guard & fan (if blades are damaged)
Remove power factor correction capacitors if equipped
Ensure that motor neutral lead is ungrounded
(1) Repeat checks listed above (2) Verify that VFD current limit and starting boost
are set correctly (5) Double check motor and feedback parameter settings and
VFD permissives (6) Repeat autotune (for vector drives) procedure (7) Consult
VFD supplier.
+
(1) Replace fuse or reset circuit breaker. Allow motor to cool down before resetting
manual protector on motor. 5
reset protector warnings (2) Verify that rated and balanced supply voltage has
been restored before restarting motor. Measure voltage during restart. Ensure that
steady state supply voltage at motor terminals is within limits (see section 3.4.1.3).
(1) Verify that motor & load turn freely. Repair binding components as needed (2)
Reduce driven load to match motor capacity or increase motor size to match load
requirements.
(1) Check fault codes on VFD and follow VFD troubleshooting procedures (2)
Verify that VFD input voltage is balanced and within limits (3) Remove excessive
mechanical load if present.
5
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(-
Match motor lead wiring to nameplate diagram.
(1) Ensure that steady state supply voltage at motor terminals is within limits (see
section 3.4.1.3). Correct as needed (2) Obtain correct motor to match actual supply
voltage.
Determine correct motor size and contact motor representative to obtain
replacement motor.
Motor may be too small for load. Record acceleration time. Start capacitors may
fail if acceleration time exceeds 3 seconds.
(1) Check to make sure motor & load turn freely (2) Disconnect motor from load &
ensure motor turns freely
[Single Phase] Reconnect motor according to wiring schematic provided.
Some motors are non reversible
[Three Phase] Interchange any two power supply (phase) leads.
0
(1) If motor current exceeds nameplate value, ensure that driven load has not
increased. Correct as needed. (2) If new motor is a replacement, verify that the
rating is the same as the old motor. If previous motor was a special design, a
general purpose motor may not have the correct performance.
Most motors are designed to operate in an ambient up to 40 C. (See section 4.2.2
Hot Surface Caution)
Remove foreign materials – clear vent openings, fan guard air inlets and frame
fins (TEFC motors)
TEAO (Totally Enclosed Air Over) motors: Measure airflow next to motor surface
and obtain minimum requirements from motor manufacturer.
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See section 1.1 for automatic and manual
8 & 3
: Contact service shop to check capacitor.
Note:
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