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Home > Knowledge > New energy drive motor insulation measurement and resolver parameter measurement method

New energy drive motor insulation measurement and resolver parameter measurement method

Author:F-Diesel Date:August 21, 2025 3:38 AM Tag:[ voltage , motor electrical , 500VDC insulation resistance measurement , EV motor insulation measurement ]
This knowledge base introduces or describes the Complete guide to EV motor insulation and resolver measurement methods, including phase-to-ground insulation resistance testing, resolver sine/cosine/excitation resistance checks, and detailed standard values for CMA, M4, and G7 motors. Learn correct testing procedures, equipment requirements, and performance standards.

Table of contents

1、Motor Insulation Measurement Method

         1.1.Use a dedicated insulation meter with the black

         1.2.Generally, a qualified insulation resistance of 100MΩ is displayed

2、Resolver Measurement Method

 

1、 Motor Insulation Measurement Method

 

 

Requirements  Standard  Equipment 
Phase-to-Ground 500VDC Insulation Resistance  >100MΩ  Insulation Meter

 

 

 

1.1 Use a dedicated insulation meter with the black test lead connected to ground and the red test lead connected to a phase. Then press and hold the TEST button to test.

1.2 Generally, a qualified insulation resistance of 100MΩ is displayed, meeting the insulation requirement.

Use a dedicated insulation meter with the black test lead connected to ground and the red test lead connected to a resolver pin. Then press and hold the TEST button to test the three-phase (U, V, W), sine, cosine, excitation, NTC1, and NTC2 insulation. The standard is ≥100MΩ @ 500VDC.

 

No. Measurement Location Standard  Equipment 
1  NTC 1, NTC 2, ground insulation ≥100 MΩ @ 500 VDC Insulation Meter
2 Resolver: Sine, cosine, excitation ground insulation  ≥100 MΩ @ 500 VDC  Insulation Meter
3 Three-phase U, V, W ground insulation ≥100 MΩ @ 500 VDC Insulation Meter

 

2、 Resolver Measurement Method:

 

Set the meter to the ohm range. Check the units in the upper right corner of the screen: MΩ, Ω, KΩ, diode; for CMA motor resolver resistance, select Ω.

Use a dedicated multimeter and connect the black and red test leads to the sine (positive and negative) poles, cosine (positive and negative) poles, and excitation (positive and negative) poles, respectively, to measure the sine, cosine, and excitation resistance values.

 

 

 

 

（P3）Motor electrical performance test - standard  
Serial number Measurement position  Standard
1 Low voltage connector pin pin rotary variable resistance excitation (11, 12) 24.3-29.7Ω@25℃
2 Low voltage connector pin pin rotary variable resistance SIN (9, 10) 54-56Ω@25℃
3 Low voltage connector pin pin rotary variable resistance COS (7, 8)  57.6-70.4Ω@25℃

 

（M4）Motor electrical performance test - standard
Serial number Measurement position Standard 
1 Low voltage connector pin pin rotary variable resistance excitation (11, 12) 24-30Ω@25℃
2 Low voltage connector pin pin rotary variable resistance SIN (9, 10) 57-71Ω@25℃
3  Low voltage connector pin pin rotary variable resistance COS (7, 8) 45-66Ω@25℃

 

(G7) Motor electrical performance test - Standard
No. Measurement position Standard
1 Low voltage connector pin pin resolver resistance excitation (11, 12)  20.6±2Ω@25℃
2 Low voltage connector pin pin resolver resistance SIN (9, 10) 49.8±5Ω@25℃
3 Low voltage connector pin pin resolver resistance COS (7, 8) 55.3±5Ω@25℃