
Flameproof motors | 61
www.weg.net
Abnormal noise during
operation on load.
Mechanical causes;
The noise normally decreases when the
rotation drops; see also:
"
Noisy operation
when uncoupled”
Electric causes;
The noise disappears when the motor is
switched-off. Contact WEG;
When coupled noise appears;
When uncoupled the noise
disappears.
Defect on the transmission components or the
driven machine;
Check the power transmission, the coupling
and the alignment;
Defect on the gear transmission;
Align the driven system;
Base not aligned/leveled;
Realign/level the motor and the driven
machine;
Defective balance of the components or the
driven machine;
Perform new balance;
Defective coupling;
Repair or replace the coupling;
Wrong rotation direction of the motor;
Invert 2 phase connection.
Noisy operation when
uncoupled.
Unbalance;
Noise continues during deceleration after
switching-off the voltage;
Perform new balancing;
Interruption on one phase of the stator winding;
Measure the current input of all the
connecting cables;
Fastening bolts loose;
Retighten and lock the bolts;
The rotor balance conditions get worse after
coupling assembly;
Balance the coupling;
Resonance of foundation;
Adjust the foundation;
Motor frame bending;
Check base flatness;
Bent shaft;
The shaft may be bent;
Check the rotor balance and the
eccentricity;
Non-uniform air-gap;
Check the shaft bending or the wearing of
the bearings;