Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!usc!orion.oac.uci.edu!cerritos.edu!arizona.edu!arizona!naucse!rrw From: rrw@naucse.cse.nau.edu (Robert Wier) Newsgroups: sci.electronics Subject: Re: Sidereal Time Clock Message-ID: <3122@naucse.cse.nau.edu> Date: 10 Jan 91 19:36:01 GMT References: <5711.277c4a63@nuhub.acs.northeastern.edu> <5972@mint17.UUCP> <9851@as0c.sei.cmu.edu> Organization: Northern Arizona University, Flagstaff AZ Lines: 46 In talking about synching power generators with a grid, about a year ago, I lead an IEEE student group tour down to the Childs hydro power plant (central Az). This is very interesting since it was one of the first plants operating in Az (and the oldest still on line). You go look at the equipment, and much of it is dated 1890 or 1905. Anyway, it is a very small operation, about 500kw run from a small resevoir fed by springs. If I remember correctly there is about 300' of head. When it was first brought online, they said it supplied all the needs of Northern Arizona, and half of Phoenix! I was suprised to learn when the plant was shut down that they didn't disconnect from the grid (for example, to clean the pipes and turbine valves). They just let the grid power the generators as large electric motors. Said it was a whole lot easier than trying to bring them up from a dead stop and re-synch them to the grid (which had to be done by hand). They had the original Westinghouse synch-meter which was about the size of a wall clock. It as (was) calibrated in + and - degrees, with a big crank to make speed adjustments. The tech on duty indicated that he was there once when someone goofed and put the plant on line with a 3 degree difference. He said it sounded like a cannon going off and shook the whole building. Didn't do any damage though. I found it suprising that it was still economical to operate a plant of this size. But basically the capital expense was paid off long ago, the equipment doesn't wear out very fast, and it only takes a couple of guys to run it. Mainly they just have to keep watch on the resevoir water level to make sure it doesn't get too low. It was nice for the students as well since all of the equipment is open-frame, and you can see the rotors going 'round and so forth since there aren't any covers. REALLY noisy, though. - Bob Wier -------------- insert favorite standard disclaimers here ---------- College of Engineering Northern Arizona University / Flagstaff, Arizona Internet: rrw@naucse.cse.nau.edu | BITNET: WIER@NAUVAX | WB5KXH or uucp: ...arizona!naucse!rrw