79
Fault Probable cause
Motor without load, current is
balance, but the value is large
①Reduce too much number of stator windings when
repair motor winding.
②Power voltage too high.
③Y connected motor wrongly connect to Δ
④During motor assemble, rotor oppositely connects,
make stator core unaligned, effective length shortens.
⑤Air gap over large or uneven.
⑥When remove old winding for overhaul, use improper
way that burn the iron core.
Abnormal noise when motor runs
①Insulation paper of rotor and stator or slot wedge
rubs.
②There is foreign body as sand in oil or bearing wear.
③Stator and rotor core loosen.
④Bearing lack oil.
⑤Air duct stuffing or fan rubs the fan housing.
⑥Stator and rotor core rub.
⑦Power voltage too high or imbalance.
⑧Wrongly stator winding or short circuit.
Big motor vibration during running
①Too big wear bearing clearance
②Uneven air gap
③Rotor imbalance
④Revolving shaft bend.
⑤Iron core deforms or loosens.
⑥Housing or basic capacity is insufficient.
⑦Motor foot screw loosen
⑧Open circuit of cage rotor open welding, open circuit
of wound rotor, or winding fault with stator.
Bearing overheat.
①Over much or few grease
②Bad oil quantity and contains impurity.
③Mismatch between bearing and journal or end
cap(too loose or too tight)
④Eccentricity of bearing bore, rub with the axle.
⑤Motor end cap or bearing cap not even assembled
⑥Coupling between motor and load not adjust
⑦Too large or too small bearing clearance
⑧Motor axle bend.
Motor overheating or smoking
①Too high power voltage, greatly increase the core
heating.
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