Wednesday, April 11, 2012

Medium Voltage Fun

So, some of you may think 15KV is High Voltage but in reality it is really Medium Voltage. This morning was all about lifting a 15KV 2400KVAR capacitor bank and a four place 15KV / 1250 Amp Trayer Switch into place All this is to control / feed a 15KV / 4160V step down transformer that will end up powering a 3000HP induction motor and variable frequency drive to power the main propeller of our wind tunnel. This will be quite the upgrade from the WW2 surplus 1000HP synchronous motor we are currently using. The existing was surplus when it was sent here and it has served well past it's expected lifetime. It is now past due for retirement. Add to that the ancient transformers that are in the low right corner of the picture. That is the original gear installed to power the tunnel and the crews that care for the power distribution here at the University are more than happy to see it all go away.
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8 comments:

  1. AnonymousApril 11, 2012 at 8:59 AM

    I worked in a manfacturing plant that had one large old 800(?)HP synchronous motor left over from the 1940's. The plant utility engineers loved it. They ran it idling, meaning not doing any useful work, to use for power factor correction. I am surprised the Aggie Engineers didn't want to keep it around.

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  2. TXGunGeekApril 12, 2012 at 5:16 AM

    Actually, I went back and changed the description. Not sure where it came from. We installed a 2400KVAR capacitor bank. That is there for line conditioning. About 600 of it is for existing phase issues and the rest is for the induction motor should we ever run it with the back up soft starter instead of the VFD that is the primary control. Running the synchro motor would just be a waste of power at that point.

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  3. AnonymousApril 12, 2012 at 9:54 AM

    According to our engineers at the time, running the already depreciated 800 HP synchronous motor doing no useful work (I think it turned a fan) and paying for current to it was still economically better than paying extra for having a low PF or buying a new capacitor bank for PF correction.

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  4. KevinApril 12, 2012 at 3:16 PM

    Whose drive? And going from 1kHP to 3kHP? That's a pretty significant step up!

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  5. TXGunGeekApril 12, 2012 at 6:05 PM

    Kevin, I can't comment on the manufacturer of the drive, it is a prototype, actually a beta unit so we are not disclosing that part. THe motor is a TECO/Westinghouse. Yes it is a big jump in power but the prop is rated and structural analysis says the tunnel will handle it. We likely won't be pushing it that hard to start though. We have a series of typical tests coming up before we have any time to really characterize it so we can push.

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  6. KevinApril 13, 2012 at 11:27 AM

    Somebody else is joining the party? Interesting. I figured it was an ABB, Allen-Bradley, Cutler-Hammer, Siemens/Robicon or Toshiba. 3kHP @ 5kV is pretty standard for all of those guys.

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  7. TXGunGeekApril 13, 2012 at 12:41 PM

    Yup, there is a new kid soon to be on the block. They were looking for so,eplace that was not mission critical application that they could test and we fit that bill with a soft satart as an alternate way to just run the motor at 2100RPM straight. we have some complicated switchgear in front and behind the SS and VFD to switch between the twoo in case we have issues with the VFD. Promises to be interesting.

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  8. TXGunGeekApril 13, 2012 at 2:16 PM

    WOW did I suck at that type job.

    someplace
    start
    1200RPM
    We
    two

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