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I just read IEC 63026 and can't find any reference to VLF withstand testing nor using VLF for TD and PD testing. Am I missing it or did they exclude it in the 2019 version?

Yes, I know what pd is. If you can't answer the question, why reply.

Does anyone know of any good books or articles on the methods to design PD free transformers, up to maybe 100 kVac?

Thanks Muthu for the info. I'll try to write up today an explanation of the motor test set's function with its multiple voltage taps for gradual motor starting. They are worried about the effects on their system and need assurances. Thanks to all for your response. This is a great forum for...

Thanks Mutha. Good to hear from you

Thanks all. But one question still remaining is: if the motor under test is brought up to speed slowly, and never slammed on line, why do we care about starting currents, locked rotor currents, no load or full load currents in terms of the effect on the utility of the service is designed for...

The percent reduction will be the minimum needed to break over the torque to get it spinning, probably 60 - 65% of nominal. The testing will be occasional as we rewind motors, but not everyday. The soft start is the reduced voltage starting. Thanks

Using a Motor Test Set with many reduced voltage taps. Utility worried about inrush on a 5000 HP, 12470V motor. Since we will be starting at lower voltages and working up, there will be no full v online starting currents. When will my max current occur? Need they worry?

Thank you

Is this standard under review for an update. Will the new version include the use of VLF 0.10 Hz frequency for tan delta/power factor testing?

Can anyone recommend a book or other materials to teach the design of oil insulated high voltage capacitors used in charge/discharge applications like thumpers/cable testers, energy pulse supplies, etc. Typical ratings are 10-20 kVdc @ 500J - 2000J.

Looking for company/consultant with design experience in high voltage AC supplies, particularly transformer design for low PD output. Also, bushing design for the same.

Any Siemens people out there to help? I am trying to find out the capacitance of a large HV motor so that we can size the power required from and AC hipot to perform overvoltage testing. I have the nameplate data.

Please, if anyone reading this can help, it would be greatly appreciated.

Can anyone recommend one or more books for the design of high voltage, oil immersed transformers, particularly the design and processing steps necessary for low pd output. Thank you.

In terms of volts/mil, are these two equal in their voltage ratings. When oil soaked following a full vpi and when not soaked.

I understand, but probably many would opt for VLF is they understood the economics and convenience of using VLF over a multi-ton power frequency set. For withstand testing it should not be objectionable.

That's a pity. Why is the IEEE standard not good enough for your clients? Worldwide standards have existed for twenty years for using VLF for testing cables and terminations. Rotating machinery is a far less complicated and exacting an application than cable testing. There is nothing magical or...

I assume you are referring to clients that are testing motors and generators. For cable testing we have used VLF for withstand and TD and PD testing for over twenty years, with standards existing for almost as long. That is old news and beyond question. If you are referring to only rotating...

What you say is true, however, your testing scenario introduced cable testing into the equation, not just generator coil testing: much more complex in distinguishing what’s going on where. VLF is great for testing those high uF loads where a Parallel Resonant set or huge AC Dielectric Test Set...