GB/T 21707-2025 in English
VALIDInsulation specification for frequency conversion machine
- Issued on:2025-05-30
- Implemented on:2025-12-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$495.00
| Standard No: | GB/T 21707-2025 |
| Document status: | VALID |
| Title in English: | Insulation specification for frequency conversion machine |
| Title in Chinese: | 变频调速电机绝缘规范 |
| Language: | English |
| File Format: | Electronic (PDF) |
| Delivery: | Via email within 1~3 business days |
| Issued on: | 2025-05-30 |
| Implemented on: | 2025-12-01 |
| Superseding: |
GB/T 21707-2018 Insulation specification for variable frequency adjustable speed definite purpose converter-fed three-phase induction motors
|
| ICS Classification: | 29.160.01-Rotating machinery in general |
| Chinese Classification: | K20-Electric rotating machinery in general |
| Professional Classification: | GB-National Standard |
| Related Keywords: | variable frequency speed regulation motor insulation
high frequency impact test system key equipment parameter requirements high frequency impact resistance frequency conversion machine introduction analysis high frequency impact tester |
| Related Topics: | motor insulation
SS |
《GB/T 21707-2025变频调速电机绝缘规范》由TC26（全国旋转电机标准化技术委员会）归口，主管部门为中国电器工业协会。
Introduction
Analysis of the key points of standard revision
GB/T 21707-2025, as the core standard in the field of variable frequency speed regulation motor insulation, has undergone the following technical upgrades compared to the 2018 version:
| Revision areas | 2018 version | 2025 version |
|---|---|---|
| Requirements for electromagnetic wires | Only basic performance is specified | New high-frequency impact life indicators (Table 2/3) |
| Insulation structure | Unspecified classification | Classified into AD grades according to severity levels (Table 4) |
| Test methods | Unstandardized waveform measurement | Added Appendix A Waveform Parameter Measurement Guide |
Key technical requirements
1. Electromagnetic wire performance
Electromagnetic wire must meet dual indicators:
- General requirements: Enameled round wire complies with GB/T 6109.1, enameled flat wire complies with GB/T 7095.1
- High frequency impact resistance: Tested at 155℃, the minimum life of electromagnetic wires of different specifications is ≥6 hours (Table 2/3)
2. Insulation structure classification
According to the peak factor (OF), it is divided into four severe levels:
| Grade | OF Range | Typical Application |
|---|---|---|
| A(mild) | ≤1.1 | Ordinary industrial inverter |
| B(medium) | 1.1-1.5 | Rail transit traction |
| C(harsh) | 1.5-2.0 | New energy drive motor |
| D(extreme) | 2.0-2.5 | Special high voltage inverter |
Core Test Methods
1. High Frequency Impact Test System
Key Equipment Parameter Requirements:
Electromagnetic wire test (Table 5):
- Waveform: bipolar symmetrical square wave
- Frequency: 20kHz±2%
- Rise time: 100ns±10%
Insulation structure test (Table 6):
- Frequency range: 1-20kHz
- Rise time: 100-1000ns
- Temperature condition: 155℃ constant temperature
2. Special assessment of new energy vehicles
Appendix D stipulates that the drive motor needs to add:
- Mechanical vibration treatment (axial 1h)
- Temperature cycle (-45℃↔155℃)
- Oil resistance pre-test (T/CEEIA415)
Implementation Suggestions
1. Material Selection
Priority:
- Impregnating resin with heat resistance grade ≥155(F) (volatile matter ≤3%)
- Electromagnetic wire tested in accordance with GB/T 4074.7-2024
- Slot wedge materials in accordance with JB/T 10508-2020
2. Test Optimization
Suggested Measures:
- When using the high frequency impact tester, strictly calibrate the waveform according to Appendix A
- The number of model coil samples is ≥5, and the number of actual windings is ≥3
- Record the voltage fluctuation data of the whole process (B.2.2)
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