1speeding test: 250° c,45000RPM 10min, diameter, Max, between changes 0.007max for poor 0.002 Max 2fails to note tolerances size deviation according to the limit GB1804 - m. 4 insulation resistance: use ZhaoOuBiao 500V and reversing measuring insulation resistance between the collar, normal 500MOmin, hot 150 ° c, baked 30 points 50MOmin measuring insulation resistance 5 the hook