Low speed when the motor load

Reason and solutions:1.Power supply voltage is electric motor cooling fan too low,check the

power supply voltage 2.The load is too large,check the load 3.Cage rotor winding -- change the rotor broken bar 4.Wound rotor winding a bad contact or disconnect-check brush pressure,brush contact with the slip ring and the rotor winding,Motor shell charged Reason and solutions:1.Bad earth or grounding acmotor2.blogspot.com resistance is too big,good earthed by the regulation,eliminate bad earth fault 2.Winding be affected with damp rotor balancing machine be affected with damp,dry processing 3.Insulation damage,touch shell-leaching lead paint to repair the insulation,again lead.