re: micro hydro [with long distance transmission]
24 nov 1997
steve willey wrote, re:
>...4000 feet electrical transmission... 3 phase induction motors have
>been used with success but they have some difficulties about getting
i've heard of getting induction motors "redipped for generation."
perhaps they could be self-excited, or excited with an inverter.
>...harris hydro units are available with high voltage windings, and
>a specially wound transformer can be ordered...
i wonder how the house and hot water will be heated...
why not vary the load on a 110 or 220 vac induction generator using a shunt
regulator in the house, to keep the frequency constant, with some sort of
lightning arrestor in series, but no batteries, transformers, or inverters?
the cuttyhunk island windmill used to work this way, with a one-byte output
from a trs-80 controlling 8 binary-weighted 1 kw to 128kw air-cooled resistors
with series switches in parallel with the alternator. water cooled resistors
can be simpler and smaller. the strategy was simple: if the frequency is too
high, increase the binary output count to increase the load; too low, decrease
it. and keep the average exactly 60 hz, so clocks run on time.
one might use a microcontroller with commercial "lightning-proof" solid-state
relays, eg digikey's ((800) 344-4539 http://www.digikey.com) $49 parallax
basic-programmable bs2-1c and its accessories, or blue earth or micromint
equivalents. an old pc might work fine... all electronics (800) 826-5432
http://www.allcorp.com sells inexpensive used solid state relays, eg teledyne
615-8500 cat# ssrly-14u relays for $8.50 each, ul and csa listed, which can
control up to 10 amps at 250 vac. a dozen might control an 25 hp induction
motor used as a generator or an 18kw alternator. h&r (800) 848-8001,
http://www.herbach.com, sells new tm93hvc2525/6/7 600/1000/3500w 240 vac
chromalox immersion heaters for $3.50/3.95/6.95 each.