Detail of GB/T 21707-2018

Introduction of GB/T 21707-2018

GB/T 21707-2018 Insulation specification for variable frequency adjustable speed definite purpose converter-fed three-phase induction motors 1 Scope This standard gives the insulation specifications of three-phase induction motors powered by frequency converters, including terms and definitions, technical requirements and inspection rules. This standard is applicable to variable frequency adjustable speed definite purpose converter-fed three-phase induction motors with rated voltage of 1 140V and below. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 4074.7-2009 Winding wire - Test methods - Part 7: Test procedure for the determination of the temperature index of enamelled winding wires GB/T 5591.3 Combined flexible materials for electrical insulation - Part 3: Specifications for individual materials GB/T 6109.20 Enamelled round winding wire - Part 20: Polyester or polyesterimide overcoated with polyamide-imide enamelled round copper wire class 200 GB/T 7095.6 Enamelled rectangular copper winding wires - Part 6: Polyester or polyesterimide overcoated with polyamide-imide enamelled rectangular copper wire class 200 GB/T 7672.5 Glass-fiber wound winding wires - Part 5:Glass-fiber wound resin or varnish impregnated, bare or enamelled rectangular copper wire, temperature index 200 GB/T 11026.4-2012 Electrical insulating materials - Thermal endurance properties - Part 4: Ageing ovens - Single-chamber ovens GB/T 17948.1 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for wire-wound windings - Thermal evaluation and classification GB/T 17948.3-2017 Rotating electrical machines - Functional evaluation of insulation systems - Test procedures for form-wound windings - Thermal evaluation and classification of insulation systems used in rotating machines GB/T 22720.1-2017 Rotating electrical machines - Qualification and quality control tests of partial discharge free electrical insulation systems (Type I) used in rotating electrical machines fed from voltage converters JB/T 10508 Specifications for slot wedges used in small and middle size electric machines IEC 60034-18-42 Rotating electrical machines - Part 18-42: Partial discharge resistant electrical insulation systems (Type I) used in rotating electrical machines fed from voltage converters - Qualification tests 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 voltage overshoot Ub peak voltage value of the part exceeding the steady-state impulse voltage 3.2 type I insulation systems insulation system that does not bear partial discharge during its life for inverter-powered motors 3.3 type II insulation systems insulation system that bears partial discharge during its life for inverter-powered motors Note: Generally, Type II insulation systems are used for motors with rated voltage greater than or equal to 700V. 3.4 impulse voltage insulation class; IVIC safety peak-to-peak voltage, for inverter-powered motors, related to the rated voltage specified by the manufacturer and marked in the instruction manual and nameplate 4 Technical requirements 4.1 Requirements of single material 4.1.1 Magnet wire 4.1.1.1 General requirements In addition to meeting the requirements in Table 1, the magnet wire shall also be able to bear the tension, and the paint film shall not crack or lose adhesion in the winding process. Table 1 General requirements for magnet wires Magnet wire Technical requirement Enamelled round wire GB/T 6109.20 Enamelled rectangular wire GB/T 7095.6 Glass-fiber wound winding wires GB/T 7672.5 4.1.1.2 High frequency impulse resistance The chemical structure and coating process of magnet wire paint film shall make the magnet wire effectively bear the long-term high frequency impulse voltage. The high frequency impulse resistance of magnet wires shall be assessed under the conditions described in 4.3.1.2, which shall meet those specified in Table 2. Note: This standard only specifies the high frequency impulse resistance of enamelled round wire with nominal conductor diameter of 1.000 mm and grade 2 paint film thickness; for other specifications of enamelled round wire, the high frequency impulse resistance shall be determined by negotiation between the supplier and the purchaser.

Contents of GB/T 21707-2018

Contents Foreword i 1 Scope 2 Normative references 3 Terms and definitions 4 Technical requirements 5 Inspection rules Annex A (Normative) Measurement guidelines of waveform parameters of high frequency impulse tester Annex B (Normative) Test of the volatile matter of impregnating resin Annex C (Informative) Evaluation procedures for insulation systems of variable frequency motors Bibliography Figure A.1 Schematic diagram of comparison between "distorted" waveform and standard waveform Figure A.2 Schematic diagram of the bipolar symmetric square wave Figure A.3 Wiring diagram Table 1 General requirements for magnet wires Table 2 Life of magnet wire under high frequency impulse power supply Table 3 Waveform parameters of high frequency impulse resistance test of magnet wire Table C.1 Test voltage for various parts of the insulation system of a motor powered by two-level converter (peak-to-peak value) Table C.2 Relationship between stress type and IVIC