GB/T 22719.1-2008 English PDF (GBT22719.1-2008)
GB/T 22719.1-2008 English PDF (GBT22719.1-2008)
GB/T 22719.1-2008: Interturn insulation of random-wound winding for AC low-voltage electrical machines -- Part 1: Test methods
OF THE PEOPLE REPUBLIC OF CHINA
Interturn insulation of random-wound winding
for AC low-voltage electrical machines
- Part 1. Test methods
ISSUED ON. DECEMBER 30, 2008
IMPLEMENTED ON. OCTOBER 01, 2009
General Administration of Quality Supervision, Inspection
and Quarantine of the PEOPLE Republic of China;
Standardization Administration of the PEOPLE Republic of
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative References ... 4
3 Terms and Definitions ... 4
4 Test Instruments ... 6
5 Test Methods ... 6
6 Selection Principle of Test Connection ... 10
7 Test Identification ... 11
8 Automatic Testing and Automatic Identification ... 13
Annex A (Informative) Comparison Method of Impulse Waveform ... 15
GB/T 22719 Interturn insulation of random-wound winding for AC low-voltage electrical machines consists of following two parts.
?€? Part 1. Test methods;
?€? Part 2. Test limits.
This is Part 1 of GB/T 22719.
Annex A of this Part is informative.
This Standard was proposed by China Electrical Equipment Industry Association (CIBB). This Standard shall be under the jurisdiction of National Technical Committee (SAC/TC 26) on Electric Rotating Machinery of Standardization Administration of China. The responsible drafting organizations are Shanghai Electrical Apparatus Research Institute (Group) Co., Ltd, Shanghai Electrical Apparatus Co., Ltd, Shanghai Sea Eagle Electromechanical Test Equipment Factory, Jiangmen Sincere Reduction Gear Factory Co., Ltd, Zhejiang Jinlong Electrical Machinery Stock Co., Ltd, Suzhou Jufeng Insulating Material Co., Ltd, and Shanghai Shenfa Detecting Instrument Factory.
This Participating drafting organizations are Guilin Electrical Science Research Institute, and Harbin Electric Machinery AC-DC Motor Co., Ltd.
The chief drafting staffs of this standard include Zhang Shengde, Li Jinliang, Rong Weikang, Zhang Fei, Wu Yaqi, Liu Quan, Ye, Xu Weihong, Xu Baodi, Yu Longying, and Fang Jianguo.
This Part is issued for the first time.
Interturn insulation of random-wound winding for AC
low-voltage electrical machines
- Part 1. Test methods
This Part of GB/T 22719 specifies the test method - interturn insulation test of random-wound winding for AC motor.
This Part applies to random-wound winding interturn insulation test for the 3-phase or single-phase AC electrical machines of which the nominal voltage is no more than 1140V. 2 Normative References
The articles contained in the following documents have become part of this Part of GB/T 22719 when they are quoted herein. For the dated documents so quoted, all the modifications (excluding corrections) or revisions made thereafter shall not be applicable to this Standard. For the undated documents so quoted, the latest editions shall be applicable to this Standard.
JB/T 9615.2-2000 Test limits of the interturn insulation on random wound winding for AC low-voltage machines
3 Terms and Definitions
For the purpose of this Part, the following terms and definitions apply. 3.1
Comparison Method of Impulse Waveforms
A method that uses impulse voltage to test motor winding (or coil) interturn insulation. The principle is to directly apply impulse voltage wave with specified peak value and wave-front time alternately (or simultaneously) ON the same-design test winding (or coil) GB/T 22719.1--2008
7 Test Identification
This Part takes test waveform as the identification basis.
The automatic test waveform identification device which can compare and calculate test waveforms?€? difference quantity can be regarded as supplementary methods for automatic identification.
7.2 Normal Waveform
If damped oscillation waveform displayed in 2 tests overlaps basically without significant difference (abbreviation as overlap), it is called normal waveform, that is that there is no fault of interturn insulation in the test winding, please see annex A.
7.3 Fault Waveform
If abnormal waveform occurs, then there is fault of winding interturn insulation, please see annex A.
7.4 Identification of 3-Phase Motor Fault
7.4.1 3-Phase motor shall be respectively identified for fault by different wiring methods.
If 1 of 2 test waveforms displays difference, then there is fault in 1 winding; if both test waveforms display difference, then it is necessary to conduct the 3rd test. If the 3rd test waveform displays overlap, then there is fault in 1 winding; if difference still exists, then it indicates that there are faults in 2 or more windings.
For the 2nd and 3rd test, it only requires any type of wiring connection to conduct the identification.
7.4.2 Examples of fault identification of ?? (phase) connection are shown in Table 1 (see figure 1 for wiring), use same analogy for others.
The impulse voltage wave is alternatively inputted into the reference winding and test winding. It can identify whether the winding interturn insulation is good by comparing whether the damped oscillation waves are overlapped.
Because the possibility of occurring insulation fault at same degree and at same position in reference winding and test winding IS very little, so comparing the test winding and reference winding is optional. Even if the exactly-same insulation fault appears at the same time, it can be identified by appropriately converting the wiring of test sample. A.2 Non-fault Waveform Display of Interturn Insulation
For motor winding without fault in interturn insulation, the damped oscillation waveform of impulse voltage wave in reference winding and test winding shall be completely overlapped.
However, due to the fluctuations of materials and process, it often causes a little variation of winding impedance. As a result, the damped oscillation waveforms of reference winding and test winding are basically overlapped without obvious differences (abbreviated as overlap)
Special fault may exist even the test waveform is overlapped. See A 3.2 and A 4.2. A.3 Waveform Display of Interturn Insulation Fault
A.3.1 The defect (weak point or damaged point) of winding interturn insulation will be broken through and interturn short circuit will be formed, under certain impulse voltage. In this case, the comparative test waveforms will have differences in time (period), amplitude and square. The difference degree may vary according to the fault degree and position. When interturn insulation is broken through, sometimes it is accompanied with spark discharge and discharge sound, and there are discharge glitch and vibration on the test waveform. This can be a supplementary means for identifying interturn insulation faults. A.3.2 For Y and ??? connection, when interturn insulation fault exists in the common position of comparative circuit, the damped oscillation waveform of impulse voltage wave in test winding and reference winding may also be overlapped, however, the time (period), amplitude and area are different from that of fault-free waveform.
A.4 Waveform Display of Other Faults of Windings
A.4.1 Besides interturn insulation short circuit, when there are faults such as wrong connections and wrong embedding, winding impedance may be also changed. In comparative test, the damped oscillation waveform may also change.
A.4.2 The test waveform will be displayed difference if there are asymmetric faults such as partial wrong connections and wrong embedding. The difference degree varies according to the degree of mistakes. Sometimes it is very similar to the waveform of interturn insulation fault, but there is no discharge phenomenon.
A.4.3 If each phase winding has the same wrong connection or wrong embedding, the impedance is balanced and symmetrical. The two test waveforms will overlap in the comparative test, but its oscillation frequency changes, obviously the frequency is different from windings with correct connections and embedding.
A.4.4 If the winding has broken wirings, a circuit loop can not be formed, thus there will be no oscillation waveform. Sometimes there is discharge phenomenon at the broken position.
A.4.5 If the number of turns of winding is wrong, it may vary according to the percentage of wrong turn-number to the total turn-number and the test sensitivity of instruments. In the comparative test, the damped oscillation waveform will be displayed with certain differences.