Troubleshooting - BONFIGLIOLI RIDUTTORI BN Série Manuel D'installation

9 TROUBLESHOOTING

Although the electric motor has been factory tested, the following information is intended to serve as
an aid in locating and eliminating defects and faults.
In some cases, such faults may be caused by the plant or machine to which the electric motor is
assembled and hence, the cause and remedy will be described in the Manufacturer's technical
documentation for the machine/plant in question.
FAULT
The motor does not start
The motor takes a long time to
accelerate or does not come up to speed
Incorrect direction of rotation
The motor overheats
Protections tripped
Excessive running noise
Abnormal vibrations
Bearings overheated
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CAUSE
Power failure
Incorrect connections
Overload
Stator short circuit
Mechanical fault
Sudden power supply voltage drop
Excessive load applied
The motor is designed for delta
connection, but has been connected in
a star sequence
Unsuitable power voltage or frequency
Incorrect connection
Overload
Insufficient cooling
Ambient temperature too high
One motor phase interrupted
Power voltage out of range or
unbalanced phases
Overload
Stator short circuit
Defective connection
Phase interrupted
Damaged bearings
Mechanical contact
Motor and driven shafts not properly
aligned
Defective bearings
Rotating parts not balanced
Incorrect alignment
Bearings overloaded
Bearings worn
REMEDY
Inspect the cabling and protection
devices
Make sure the connections comply with
the connection diagram
Check the motor rating
This will cause the cut-outs to trip. The
motor must be repaired.
Make sure the motor and driven
machine rotate freely
Check the connections and cross-
section of the power cables
Check the motor rating (load inertia and
reactive torque)
Change the connection
Compare the power supply rating with
that of the motor itself
Swap two phases
Reduce the load
Make sure the motor is well ventilated
and clean the cooling fins
Check the ambient conditions
Check the connections
Check the power voltage or balance the
phases
Check the motor's power absorption
and reduce load if necessary
The motor must be repaired
Repair connection
Check power supply
Replace bearings
Identify the parts in contact
Align
Replace bearings
Balance the rotating parts using the half
key (rotor and coupled components)
Align
Check overhung/thrust loads
Replace bearings