Common Motor Failures and Repair Methods

A motor running sound abnormal, there is a noise 1. Fault causes ① rotor and stator insulating paper or groove wedge friction; ② bearing wear or oil sand and other foreign objects; ③ stator and rotor core loose; ④ bearing oil shortage; ⑤ air ducts or fan filler fan rubbing the windshield; ⑥ stator and rotor core rubbing; ⑦ power supply voltage is too high or unbalanced; ⑧ stator winding misconnection or short-circuit. 2. Troubleshooting ① trimming insulation, cut down the groove wedge; ② replace the bearing or cleaning bearings; ③ overhaul the stator and rotor core; ④ refueling; ⑤ clean up the air ducts; re-installation; ⑥ to eliminate the scuff marks, if necessary, the car within the small rotor; ⑦ check and adjust the power supply voltage; ⑧ eliminating the fault of the stator winding.

Second, the motor vibration in operation 1. causes ① due to wear bearing clearance is too large; ② uneven air gap; ③ rotor imbalance; ④ bending shaft; ⑤ core deformation or loose; ⑥ coupling (pulley) center is not corrected; ⑦ fan imbalance; ⑧ casing or foundation strength is not enough; ⑨ motor foot screws loose; ⑩ cage rotor weld circuit; wire-wound rotor disconnection; plus the failure of stator windings. 2. troubleshooting ① overhaul bearings, if necessary, replace; ② adjust the air gap to make it uniform; ③ correct rotor dynamic balance; ④ straighten the rotor shaft; ⑤ correction of overlapping core; ⑥ stator windings. 2. Troubleshooting ① overhaul the bearings, if necessary, replacement; ② adjust the air gap, so that it is uniform; ③ correct the rotor dynamic balance; ④ straighten the rotor shaft; ⑤ correct the overlap of the core; ⑥ re-calibration to comply with the regulations; ⑦ overhaul the fan, correct the balance, correct the geometry; ⑧ reinforced; ⑨ fasten the ground screws; ⑩ repair the rotor windings; repair the stator windings.  Third, the motor can not rotate after power, but no noise, no odor and smoke 1. causes of failure

   ① power supply is not through (at least two-phase not through); ② fuse blown (at least two-phase blown); ③ overcurrent relay adjusted too small; ④ control equipment wiring errors. 2. Troubleshooting ① check the power circuit switch, fuse, junction box, whether there is a broken point, repair; ② check the fuse type, the reason for the fuse, change the new fuse; ③ adjust the setting value of the relay with the motor; ④ correct the wiring. Fourth, the motor does not rotate after power on, and then fuse blown 1. Failure causes ① lack of a phase power supply, or the stator coil is connected to the opposite side; ② stator winding short circuit between phases; ③ stator winding ground; ④ stator winding wiring error; ⑤ fuse cross-section is too small; ⑥ power line short circuit or grounding. 2. Troubleshooting ① check whether the knife gate has a phase is not closed, can be a phase of the power circuit disconnected; to eliminate the reverse fault; ② to find out the short-circuit point, to be repaired; ③ to eliminate the grounding; ④ to find out the misconnection, to be corrected; ⑤ to replace the fuse; ⑥ to eliminate the grounding point.

Five, the motor does not rotate after power on the buzzing sound 1. causes ① stator, rotor winding circuit (a phase of broken wire) or power a phase of the power loss; ② winding lead wire start and end of the wrong or winding internal connection reversal; ③ power circuit contacts loose, contact resistance; ④ motor load or rotor stuck; ⑤ power supply voltage is too low; ⑥ small motors assembled too tightly or bearings in the grease is too hard; ⑦ bearing stuck. 2. troubleshooting ① identify the broken point to be repaired; ② check the winding polarity; determine whether the winding end is correct; ③ tighten the loose wiring screws to determine the false connection of each connector using a multimeter; use a multimeter to determine the false connection of the connectors. 2. Troubleshooting ① identify the broken point to be repaired; ② check the polarity of the winding; determine whether the winding end is correct; ③ tighten the loose wiring screws, use a multimeter to determine whether the joints are false, to be repaired; ④ load shedding or to find out and eliminate the mechanical problems; ⑤ check whether the Δ connection is also mistakenly connected to the provisions of the Y; whether due to power supply wire is too thin to make the voltage drop is too large, to be corrected; ⑥ re-fit to make it flexible; replacement of qualified grease; ⑦ repair the bearings.Qualified grease; ⑦ repair bearings. Sixth, the motor no-load current imbalance, the three phase difference is large 1. causes ① rewinding, stator three-phase winding turns are not equal; ② winding first and last end of the wrong connection; ③ power supply voltage imbalance; ④ winding there is a short-circuit between the turns, the coil reversed and other faults. 2. troubleshooting ① rewinding to make flexible; replace the qualified grease; ⑦ repair the bearings. Troubleshooting ① rewind the sub-winding; ② check and correct; ③ measure the supply voltage, try to eliminate the imbalance; ④ Cliff in addition to the winding faults.  VII, motor no-load, overload, the ammeter needle is unstable, swinging 1. Fault causes ① cage rotor guide welding or broken bars; ② wire-wound rotor failure (a phase of the circuit) or brush, collector ring short-circuiting device contact is poor. 2. 2. Troubleshooting ① find out the broken bars to be repaired or replace the rotor; ② check the winding rotor circuit and repair.  Eight, the motor no-load current balance, but the value of large 1. Fault causes ① repair, the stator winding turns to reduce too much; ② power supply voltage is too high; ③ Y connected to the motor misconnected to Δ; ④ motor assembly, the rotor mounted upside down, so that the stator core is not aligned, the effective length of the shortened; ⑤ air gap is too large or uneven; ⑥ overhaul dismantling of the old windings, the use of thermal dismantling method is not appropriate to make the iron core burnt. 2. Troubleshooting ① rewind the stator winding, restore the correct number of turns; ② try to restore the rated voltage; ③ reconnect to Y; ④ reassembly; ⑤ replace the new rotor or adjust the air gap; ⑥ overhaul the core or recalculate the winding, the appropriate increase in the number of turns.  Nine, motor starting difficulties, rated load, the speed is lower than the rated speed more 1. causes ① power supply voltage is too low; ② Δ connection method motor misconnected to Y; ③ cage rotor welded or broken; ④ stator-rotor local coil misconnection, connection reversal; ⑤ repair motor windings to increase the number of turns is too large; ⑥ motor overload. Troubleshooting ① Measure the power supply voltage, try to improve; ② Correct the connection; ③ Check the weld and break and repair; ④ Find out the misconnection, be corrected; ⑤ Restore the correct number of turns; ⑥ Load reduction.  Ten, motor overheating and even smoke 1. causes ① power supply voltage is too high, so that the core heat greatly increased; ② power supply voltage is too low, the motor is running with the rated load, the current is too large for the winding heat; ③ repair and removal of the winding, the use of hot tear down method is not appropriate, burns the core; ④ stator-rotor core friction; ⑤ motor overload or frequent starting; ⑥ cage-type rotor breaks the strip; ⑦ motor phase, two-phase operation; ⑧ rewinding of the stator winding immersion paint; ⑤ overloaded or frequent starting; ⑥ cage-rotor breaks the strip; ⑦ motor phase, two phase operation; ⑧After rewinding the stator winding dip paint is not sufficient; ⑨ high ambient temperature motor surface dirt, or blocked ventilation ducts; ⑩ motor fan failure, poor ventilation; stator winding failure (phase to phase, turn to turn short circuit; stator winding internal connection error). 2. Troubleshooting ① reduce the supply voltage (such as adjusting the power supply transformer tap), if the motor Y, Δ connection error caused by the connection should be corrected; ② increase the supply voltage or change the thick power supply wire; ③ overhaul the iron core, troubleshooting; ④ eliminate the rubbing point (adjusting the air gap or frustration, the car rotor); ⑤ load-shedding; the number of times the control of the specified startup; ⑥ check and eliminate the rotor winding faults; ⑦ to restore the three-phase operation; ⑧ the use of secondary dipping paint and vacuum dipping paint; ⑩ motor fan failure; poor ventilation; stator winding failure (short circuit between phases; stator winding internal connection error.Second dip paint and vacuum dip paint process; ⑨ cleaning motor, improve the ambient temperature, the use of cooling measures; ⑩ check and repair the fan, if necessary, replacement; overhaul the stator winding, eliminate the problem.  XI, motor bearing overheating 1. Failure causes ① too much or too little grease; ② bad oil containing impurities; ③ bearing and journal or end cap with improper (too loose or too tight) ④ bearing bore eccentric, and shaft friction; ⑤ motor end cap or bearing cover is not mounted flat; ⑥ motor and the load between the coupling is not calibrated or the belt is too tight; ⑦ bearing clearance is too large or too small; ⑧ motor shaft bending. 2. Troubleshooting ① add grease according to regulations (volume of 1/3-2/3); ② replace the clean lubricating grease; ③ too loose available binder repair, too tight should be car, grinding journal or end cap bore, so that it is suitable for; ④ repair bearing cover, to eliminate the rubbing point; ⑤ re-assembly; ⑥ re-calibration, adjustment of belt tension; ⑦ replacement of new bearings; ⑧ correction of the motor shaft or replacement of the rotor.