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Anonymous Poster #1

Slot Cells Rotor Insulation

03/19/2018 12:11 PM

Hi, we have an 200MW generator, 2 poles, 3600 RPM, moved by a turbine.

Recently we hired a Company to repair the rotor and the changed the insulation of slot cells and the inter turn insulation. But I want to know if there any way to test this insulation in order to be sure it's a good insolation and if it will be ready for this operation as high temperature, tipycally in a generator. We have tested the rotor by hipot, and impedance but we are worry about the performance of this materials. They gave un the data sheet and that paper it seems to be ok but they can write whatever they want we want to be sure before to start.
Your help will be appreciated.

Thank

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#1

Re: Slot cells rotor insulation

03/19/2018 12:32 PM

If the results of the hi-pot and impedance tests are satisfactory, the only way to assess the temperature/environmental aspects is to get samples of the materials used in the repair, and subject those samples to accelerated life testing.

There are testing facilities who can perform industry accepted test procedures to give you the information you desire.

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#11
In reply to #1

Re: Slot cells rotor insulation

03/06/2021 6:33 AM

Thanks, your answer was the key.

I just want to say thanks... We took a sample and sent to a laboratory at that time... The results were satisfactory.. Our generator is working those years without any problem.

Thanks again

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#2

Re: Slot Cells Rotor Insulation

03/19/2018 2:35 PM

I agree with post #1.

Did you use a reputable company with a certified quality system to perform the work?

Are you able to obtain the datasheets of the materials used to perform an analysis as to the suitability of the materials? This will help but won't prove workmanship quality.

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#3

Re: Slot Cells Rotor Insulation

03/19/2018 2:52 PM

You are asking total strangers questions you should have asked the company that did the work. And you should have gotten assurance IN WRITING ,from them, before starting work.

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#4

Re: Slot Cells Rotor Insulation

03/20/2018 4:10 AM

This is a big piece of kit.

  • Did the Client's Engineering Representative not discuss and approve a testing protocol before placing the purchase order for the repair?
  • Has the concept of witnessing the testing of the repaired equipment gone out of fashion all of a sudden?

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#5

Re: Slot Cells Rotor Insulation

03/20/2018 1:24 PM

3600 rpm and 200 MW generator is not a toy. How come this work has been given to an agency whom you do not trust? Why have you not gone to the original suppliers? Saving a few dollars could land you in spending much higher sum in future. Have you made quality plans for repair works? Does it include approval of use of materials? You could have gone to some reputed consultant in the field. What is the back ground of company you have given the job? There are many such questions needs to be replied before job is offered.

There are hundreds of factors to be considered before rotor insulation material is selected. Rotor is most heavily loaded (electrically as well as mechanically). Each material is chosen after long term evaluation on various parameters (electrical as well as mechanical) .

There is no use doubting material after the job has been executed.

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#6

Re: Slot Cells Rotor Insulation

03/20/2018 1:41 PM

AP, to find the answers you are looking for you need to do destructive testing and you can not do that on a completed job. You trusted them with your money you better trust their documentation. Are you looking for a way to get out of paying them? Just a question.

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#7

Re: Slot Cells Rotor Insulation

03/20/2018 9:45 PM

You'll get what you paid for!

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#8

Re: Slot Cells Rotor Insulation

03/20/2018 10:28 PM

A note to all those non-engineer accountant/project manager types, newbies, "consultants", and others who get/take a job they're not qualified to do; "The lowest bidder is not always the best bidder". Just ask the folks in southern Florida.

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#9

Re: Slot Cells Rotor Insulation

03/21/2018 6:21 AM

I don't know anything but I would guess that you would of wanted to check out the insulation, while you had a chance.

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#10

Re: Slot Cells Rotor Insulation

03/27/2018 4:11 AM

Ventilating slots are punched in the straight portion of the coils to allow for radial discharge of cooling air.

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