Three-phase asynchronous motor winding fault analysis and processing

Winding short circuit Due to poor welding or use corrosive flux,have not cleared after welding,it may cause a pot of welding or loose;Subjected to mechanical stress or collision coil short circuit,also can make the wire burned,short circuit and earth fault in a couple of wire and burn a single or a few wire short circuit,several other wire due to the increase of current temperature rise,cause heating

winding and open circuit.Generally fall into one phase winding end disconnection,turn-to-turn short circuit,parallel branch circuit,wire and burn more of a single circuit,rotor broken cage.1.The fault phenomenon Motor can't start,three phase current balance,no abnormal noise or vibration,temperature rise more than permitted or smoke.2.The reason (1) during overhaul and maintenance touch off or manufacturing quality problems.,(2) winding each element (phase) group and the winding and fixture wire connection head welding,sealing off long running overheating.(3) by the mechanical force and electromagnetic force make winding damage or pulled apart or cause drag mark.(4) or interphase short circuit and grounding caused winding coils badly burned or fuse,etc.Methods to examine 

3.(1) the method of observation.Breakpoint most occurred in winding ends,look have without touch fold,joint the presence of desoldering.(2) a multimeter.Using resistance,to "Y" type of connection to connect a table bar in the center of the "Y" shape,the other in turn in the head end of the three-phase

winding,infinite phase has a breakpoint;"Delta" connection type of short connection,measuring winding in each group respectively,infinity to breaking point.www.dongfeng-motor.com (3) test lamp.Method with former,such as bright a photograph for open circuit.(4) megohmmeter.Resistance tends to infinity (that is,not as a zero value) is the cut-off point.(5) current meter method.Motor at runtime,use current meter to measure three phase current,if the imbalance of three phase current and short-circuit phenomenon,and no is a phase winding is part of the current small short circuit fault.(6) bridge method.A phase when the motor is bigger than the other two phase resistance,resistance show that the phase winding part of open circuit fault;

(7) ac geared motor the current balance method.For "Y" type of connection,but after the three-phase winding parallel,alternating current into the low voltage large current,if the current in the

three-phase winding is greater than 10%,one end of the small current for the circuit;For "delta"

connection type,the stator winding of a contact apart first,then by interlinked into low voltage high

current,one of the small current for open circuit.ac motor wind generator (8) broken cage detector

test.Check,if the broken rotor cage millivoltmeter readings should be reduced.4.Open circuit

processing method (1) the opening in the end,the connection after welded,the package on insulation

materials,set on the insulation tube,good binding,dry again.(2) the winding due to interturn,interphase short circuit and grounding,etc and cause severe charred generally should change new windings.(3) to the breaking point in the slot,belong to a few breakpoints for emergency treatment,the grouping elimination method is adopted to find the breakpoint,and broken in winding connection and the insulation used after 220v ac electric motors qualified.(4) can be used for broken squirrel-cage rotor cage welding,cold connection or change the original repair.