Method of insulating a motor

A method of insulating a motor, comprising:

• providing a impregnating resin;
• heating up a motor winding with electricity to 100-120° C., and potting the motor winding with the impregnating resin for 2-5 min at that temperature;
• heating up the motor winding with electricity to 140-160° C. and trickling the impregnating resin for 3-8 min for insulation;
• heating up the motor winding with electricity to 165-175° C., and curing for 15-45 min, wherein a preparation method of the impregnating resin comprising a recited series of steps:
• (1) heating a polyesterimide resin to 100-110° C., adding a modified epoxy resin with evenly stirring, and then cooling to 60° C. and below, adding an active monomer, a polymerization inhibitor, additives, after that stirring evenly to obtain a resin mixture;
• (2) adding the resin mixture obtained in step (1) to a kettle mixer, setting a stirring speed at 1000˜2000 r/min for homogeneous emulsification, and adding an inorganic filler to the kettle mixer to stir and disperse, then changing speed to 6000-13000 r/min to stir and emulsify for 2-3 h with the temperature controlled below 60° C.;
• (3) after homogeneous emulsifying reducing the stirring speed to 500-1000 r/min, cooling down to a temperature below 45° C., adding a curing agent and an initiator to stir and disperse for 1-2 h to obtain the impregnating resin.