Construction machinery use collector device maintenance rules?

Quarterly needed after a power outage 220v ac electric motor soverhaul:(1) cleaning the dust,tighten bolts.(2) porcelain should be in good condition,if there is any breakage,should be replaced.(3) the contact between www.dongfeng-motor.com the brush and slip ring should be good,spring pressure is appropriate.(4) the slip ring surface such ac geared motor as a

depressed,burr,should be grinding.(5) check the presence of flashover phenomenon,measuring insulation resistance.(6) correction difference of each ring,which make the level of the ring to meet 220v ac electric motors the design requirements.