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Re: [microhydro] Re: correcting power factor

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  • evansengineering@cs.com
    With regard to all the problems being talked about in relation to difficult power factor regulation, doesn t anyone agree with me that a standard robust
    Message 1 of 9 , Oct 1, 2000
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      With regard to all the problems being talked about in relation to difficult
      power factor regulation, doesn't anyone agree with me that a standard robust
      brushless alternator is easier and cheaper than having all these capacitor
      banks and unknown line characteristics and hence very unpredictable voltages ?

      Rupert
    • microhydro@dplus.net
      Rupert - Yes - I agree - induction machines are w/out brushes and can often more readily handle runnaway speed - these are the only two good aspects of
      Message 2 of 9 , Oct 2, 2000
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        Rupert -
        Yes - I agree - induction machines are w/out brushes and can
        often more readily handle runnaway speed - these are the only two
        good
        aspects of induction generators in my opinion.
        A proper sync. generator gives far better eff and positive control
        of power facter. Especially in the case example that started this
        discussion - moderate capacity site at the end of a weak grid
        extension - Power factor control is essential to reduce var usage -
        even contribute vars to a weak system is a real benefit.
        Even in the small system running mostly transformers for
        flouresent lamps - adjustable ( with excitation control) PF would
        greatly simplify the problem.
        Best Ron

        --- In microhydro@egroups.com, evansengineering@c... wrote:
        > With regard to all the problems being talked about in relation to
        difficult
        > power factor regulation, doesn't anyone agree with me that a
        standard robust
        > brushless alternator is easier and cheaper than having all these
        capacitor
        > banks and unknown line characteristics and hence very unpredictable
        voltages ?
        >
        > Rupert
      • Stewart Craine
        Thanks to all for the advice so far. I believe the peltric sets here are all induction generators, and I think they re brushless, but maybe Ghanashyam can
        Message 3 of 9 , Oct 4, 2000
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          Thanks to all for the advice so far. I believe the peltric sets here are all
          induction generators, and I think they're brushless, but maybe Ghanashyam
          can correct me on this one. Each house will probably have their own switch,
          so there could be quite a variation in load. I'm pretty sure all the PFs
          were lagging, but I'll have to confirm that. The voltage will be about 220
          and a maximum of 2A generated (around 4 - 4.5 kW).

          Cheers,
          Stew


          Stewart Craine
          LEDCO, Nepal
          www.ledco-nepal.com
          stewart@...

          -----Original Message-----
          From: ellwood@... [mailto:ellwood@...]
          Sent: Sunday, October 01, 2000 8:07 AM
          To: microhydro@egroups.com
          Subject: [microhydro] Re: correcting power factor

          >150 households to power about400 lamps.

          Does each house hold have there own switch for the lights or are they
          controlled by several master switches? If controlled by several
          master switches it would be easier to control pf of each bank of
          lamps
          seperately.

          > have shown that locally available 7W-15W CFLs with integrated
          ballasts have
          > power factors of 0.5-0.6, while the non-integrated CFLs with
          magnetic
          > ballasts have PFs of 0.3-0.4.

          As Hugh suggests if some have a leading power factor maybe a
          combination of both leading and lagging may work.

          Are you using an induction generator? If so the excitation
          capacitance will be used in trying to pf correct the laod and
          generation will be lost.

          To work out the pf of the load I would probably need to know the
          voltage / current and the percentage of how many lamps are expected
          to
          be on at a time. With that information it shouldn't be to hard to do
          the calculations.

          Richard Ellwood
          New Zealand




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