GB/T 12665-2008 English PDF (GBT12665-2008)

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GB/T 12665-2008: Requirements of damp-heat testing of electrical machine for service in general environmental condition
GB/T 12665-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 19.040
K 20
Replacing GB/T 12665-1990
Requirements of damp-heat testing of electrical machine
for service in general environmental condition
ISSUED ON. JUNE 13, 2008
IMPLEMENTED ON. MARCH 01, 2009
Issued by. General Administration of Quality Supervision, Inspection
and Quarantine of the People’s Republic of China;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1  Scope ... 4 
2  Normative References ... 4 
3  Test method ... 4 
4  Technical requirements ... 7 
5  Inspection rules ... 10 
Foreword
This Standard replaces GB/T 12665-1990 Requirements of damp-heat testing of electrical
machine for service in general environmental condition.
Compared with GB/T 12665-1990, the main changes of this Standard are as follows.
— Update the reference standards;
— Add the severity condition 55°C to damp-heat test in 3.2;
— Update figure 1;
— Add the article “3.4 Measurement of leakage current”;
— Change the “alternate damp-heat test” to be “damp-heat test” in 4.1.
This Standard was proposed by China Electrical Equipment Industrial Association
(CEEIA).
This Standard shall be under the jurisdiction of Subcommittee 1 of Low-power Electric
Machine of National Technical Committee 26 on Electric Rotating Machinery of
Standardization Administration of China.
Drafting organizations of this Standard. China National Electric Apparatus Research
Institute (CEI), and Hengdian Group Lianyi Electrical Machine Co., Ltd.
Main drafting staffs of this Standard. Yan Jinglian, Liao Guoqing, and Shen Tujun.
This Standard replaces the following historical edition.
— GB/T 12665-1990.
Requirements of damp-heat testing of electrical machine
for service in general environmental condition
1 Scope
This Standard specifies the damp heat test method, technical requirements and inspection
rules of the rotating electrical machine for service in general environmental condition.
This Standard is applicable to all kinds of rotating electrical machines (except mini-type
control machine, hereinafter referred to as electrical machine). According to provisions of
GB 755, the relative humidity of service environment is. the average maximum relative
humidity in the wettest month is 90%; and the average lowest temperature in that month is
not higher than 25°C; it shall meet the requirements of this Standard.
2 Normative References
The articles contained in the following documents have become part of this Standard
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.
GB 755-2000 Rotating electrical machines - Rating and performance (idt IEC
60034-1.1996)
GB/T 2423.3-2006 Environmental testing for electric and electronic products - Part 2.
Testing method test Cab. Damp heat Steady state (idt IEC 60068-2-78.2001)
GB/T 2423.4-1993 Basic environmental testing procedures for electric and electronic
products－Test Db. Damp heat, cyclic (eqv IEC 60068-2-78.1985)
3 Test method
3.1 Preparation before the test
3.1.1 Test equipment and instruments
Damp heat test chamber shall meet the requirements in Chapter 3 of GB/T 2423.4-1993.
The voltage class of megameter for measuring insulation resistance shall meet the
provisions in Table 1.
3.4 Leakage current measurement
After damp heat test, the leakage current of the electrical machine shall comply with the
provisions of the relevant product standards.
3.5 Withstand-voltage test
After measuring insulation resistance and leakage current of test samples, the insulation
withstand-voltage test shall be immediately carried out, which shall be generally in the test
chamber; when conditions do not permit, the high-voltage electrical machines or
components and parts can be removed from the test chamber for testing, however, it must
be completed within 6 h. If there is doubt on the insulation breakdown, it allows re-testing
immediately without changing the test status, and the test voltage shall be still based on
the provisions of Chapter 4.
3.6 Operating performance inspection
The inspection on the operating performance of electrical machine shall be completed
within 48h after being removed from the test chamber; the operating performance
inspection shall be carried out in energizing and operation; and the performance
requirements of electrical machine shall be specified by the various professional product
standards.
4 Technical requirements
4.1 Insulation performance
The complete electrical machine or components and parts (only for large electrical
machines) shall meet the following conditions after damp heat test specified in Article 3.2.
4.1.1 The insulation requirements of complete electrical machine after damp
heat test
The complete electrical machine shall meet the following requirements after damp heat
test.
a) The insulation resistance of the electrical machine windings against shell and the
windings shall not be less than the following values.
The electrical machine with the rated voltage of 220 V and above shall be
determined according to formula (1).
R P
 ... (1)
Where.
R — the insulation resistance of the electrical machine windings, in megaohms
The middle-large electrical machine can be installed with anti-damp heater; the heater
power shall be able to make the temperature inside the shell 5 °C higher than room
temperature, and ensure that the heating temperature cannot cause its nearby insulation
more than the allowable temperature of this insulation.
The damp heat test can not be carried out on the electrical machine installed with heater.
4.4 Others
When the constant damp heat test is carried out on the relevant professional products
according to 3.2, it shall be according to the specified corresponding test cycles and the
technical requirements after damp heat test, but shall not be less than the requirements
specified in this Standard.
The damp heat test cannot be carried out on the large steam turbine generator and
hydraulic generator and whether to install heater shall be consulted and determined by the
user with the manufacturer.
5 Inspection rules
5.1 Overview
Damp heat test shall be carried out under the following conditions.
When the damp heat resistance performance affecting product is changed by the
product design finalizing or design, process and materials are used.
Whether to carry out regular sampling test on products and its deadline shall be
specified by various professional product standards.
5.2 Sampling method
The damp heat test of the electrical machine allows to sample the representative products
for testing in a random sampling method in the same series of products with
same-structure, same-process and same-material; if passing the test, it shall be accepted
that the products with same-structure, same-process and same-materials (including the
derived series and the similar products with the same center height range) are qualified.
5.3 Number of test samples
For the electrical machine under damp heat test, the number of components and parts
shall be according to the following provisions.
For the electrical machine with the center height of 315 mm and below,...