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  1. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    Muthu, My apologies on the readings. These were of the cables, not the transformer. the readings were taken with the cutouts open, cable disconnected from the transformer. Only thing that was still connected were the 12KV lightning arrestors on the pole. One of these could be bad, we are...
  2. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    Any good write-ups on a turns ratio test? We are trying to avoid paying a testing company $3000++ to come out tell us we have a bad transformer. If we can ascertain that it is bad, we'd rather put the money towards a rebuild or replacement. Given that it has never had an oil or any other test...
  3. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    Bill, I will check for connection between primary/secondary with a megger. We meggered everything at 1000V (obviously not that helpful for the 12 KV side, but a good sanity check on the 480 side)., but I did not check from X1--H1, etc. That is an interesting solution to grounding the system...
  4. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    Wolf, that is what I thought. I am very much comfortable with a star arrangement. This generator has only 3 leads so we are stuck with what we have. It seems like there should be some sort of grounding scheme on the 480V side, perhaps a zig-zag transformer. Rasevski, I believe there is phase...
  5. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    Thanks for the additional help everybody. I'm not sure how the 480V lightning arrestor was connected, as all that remains of it is a pile of debris and a scorch mark on the concrete wall. I will ask the owner to see if he remembers. I'm not quite sure why it was even installed, and putting it...
  6. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    Thank you for the insight guys, I had not thought of the lightning arrestor creating a phase to phase fault. I have not worked with many ungrounded systems, and so I take ground for granted. Why would you build an ungrounded system like this, and what would be the preferred way to establish a...
  7. mhulbert

    250 KVA Hydro Generator - Pick apart the design

    I have a client that has a small hydro generating setup. It's about 30 years old and experiencing some problems. I think there are a few areas of the design that may need fixing. Some of this is outside what I deal with typically, and I would like you guys and gals to give me your opinion. The...
  8. mhulbert

    MP3 Player

    Gilderfluke's site is back up, here is a link to the industrial MP3 player: http://www.gilderfluke.com/index.php?main_page=product_info&cPath=16_26&products_id=33 Also, it can be controlled by RS232 which may eliminate your need for a silence detection scheme. -mike-
  9. mhulbert

    MP3 Player

    You could use this small MP3 player by a company called Gilderfluke: (their website is currently down, but here is a google cache page)...

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