IEE Std 522
IEE Std 522
(OP)
Dear all
I was taking a look of the IEEE Std-522 and in this document the test sequence for a new pre formed winding is showed at pag.7 the summary is:
1. Test all coils prior insertion 2. Test all coils after assembly into the stator with out grouping and with out insulate nothing 3. Once all groups are connected before insulating series connections and before connect the groups to create the phases
4. After all connections are made and insulation applied.
The question is : For a 6 Kv Motor wich are the Voltages levels to use in each numbers of the above procedure.
Can someone indicate a best procedure?
Thanks and regrads
Carlos
I was taking a look of the IEEE Std-522 and in this document the test sequence for a new pre formed winding is showed at pag.7 the summary is:
1. Test all coils prior insertion 2. Test all coils after assembly into the stator with out grouping and with out insulate nothing 3. Once all groups are connected before insulating series connections and before connect the groups to create the phases
4. After all connections are made and insulation applied.
The question is : For a 6 Kv Motor wich are the Voltages levels to use in each numbers of the above procedure.
Can someone indicate a best procedure?
Thanks and regrads
Carlos





RE: IEE Std 522
As the standard says, the impulse test voltage should be agreed upon by the manufacturer and the end user depending on the anticipated level of transients. Most often, the 3.5 pu test voltage is used for all stages of testing form wound coils and assembled motors. To calculate the 3.5 pu test voltage, multiply the line voltage by 2.86. So a new 6 kV winding should be tested with about a 17 kV peak impulse. This standard states that the maintenance impulse test voltage should be 75% of new or about 13 kV peak.
The IEC 34-15 equivalent standard recommends an even higher test voltage (4V +5 kV). It recommends a test voltage of 29 kV peak on an assembled varnished 6kV motor.
This proof test voltage may seem excessive, but, it is necessary to ensure that a motor will be reliable. Due to the high distributed capacitance of a large motor, a voltage transient stresses primarily the coils close to the motor leads. These coils must be able to withstand an occasional very high turn to turn transient stress.
I have worked around a lot of motor manufacturing plants and find that reputable manufacturers can supply coils which can withstand the IEC recommended test voltages.
RE: IEE Std 522
Good information.
Thanks
Carlos
RE: IEE Std 522
BUT, the customer and the shop also need to understand the implications.
You should not be using full final test voltage on green coils
Further, "Effect of Surge Testing on Unimpregnated Ground Insulation of VPI Stator Coils" by Stranges, Snopek, Younsi (*), Dymond states:
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 38, NO. 5, SEPTEMBER/OCTOBER 2002
* Dr. Younsi occassionaly visits our forum. Hopefully he will visit this thread.
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RE: IEE Std 522
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RE: IEE Std 522
It is reasonable to conclude the current lower value 40-60% is a result of articles similar to the one linked above.
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