JB/T 7785-1995 Rapid test and evaluation method for the life of low voltage motor insulation structure (step stress method) JB/T7785-1995 standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T7785-1995www.bzxz.net
Rapid test and evaluation method for the life of insulation structure of low-voltage motor (step stress method)
Published on October 9, 1995
Ministry of Machinery Industry of the People's Republic of China
Implementation on October 1, 1996
Mechanical Industry Standard of the People's Republic of China
Rapid test and evaluation method for the life of insulation structure of low-voltage motor (step stress method)
Subject content and scope of application
JB/T 7785-1995
This standard specifies the rapid test and evaluation method for the life of the insulation structure of the stator winding of a low-voltage motor. This method uses the whole machine as a specimen, achieves the purpose of rapid testing in a temperature stepping manner, and obtains the maximum likelihood estimate of the average life of the insulation structure. This standard applies to three-phase and single-phase low-voltage motors of various heat resistance grades operating under general conditions. Their lifespans follow a log-normal distribution. The tested insulation structure is compared with the reference (benchmark) insulation structure in the same test to make a relative assessment. 2 Referenced standards
Basic technical requirements for rotating electrical machines
JB/DQ3205 Test methods for the life of low-voltage motor insulation structures as a whole machine 3 Terms and symbols
3.1 Forward and reverse rotation
In the acceleration test, the sample motor operates at a certain time rhythm in the form of "power-on operation →+power-off coasting-→reverse power-on reversal →>power-off coasting", which is called forward and reverse rotation, also known as reverse starting operation. 3.2 Temperature step accelerated life test:
Specifies a set of test temperature levels higher than the normal operating temperature—T
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