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Re: Need a variable-speed 2hp or greater AC motor for serious gap drive
Original poster: "Nick Andrews by way of Terry Fritz <teslalist-at-qwest-dot-net>" <nicothefabulous-at-hotmail-dot-com>
Well, the squirrel cage on a swamp cooler (evap) is pretty good size and
spins fairly fast, and they are driven by 1/4 up to 1-1/2hp motors just
fine. And they (obviously) move a fair bit of air... Much larger and more
rotating mass than most rotor discs I've seen.
>From: "Tesla list" <tesla-at-pupman-dot-com>
>Subject: Re: Need a variable-speed 2hp or greater AC motor for serious
>Date: Mon, 02 Jun 2003 06:33:03 -0600
>Original poster: "W.R. Langston by way of Terry Fritz
>Funny you should ask. My son, the currently practicing physicist
>(government paid research physicist -- a shade too accustomed to the
>concept of over-engineering IMHO ;-), has machined as close to a
>bulletproof rotary gap as my eyes have ever set on. Somehow he has managed
>to get almost all the people in his section excited about this project and
>directly in on the design and machining work -- if you've ever worked in a
>government lab, that should explain everything about what is going on here.
>It looks like it will require 1 1/2 hp to cause this thing to quiver, let
>alone spin. However, once in motion, it should be able to reverse feed
>Hover for a few seconds as it slows down.
>If there has ever been something that looked virtually indestructible,
>this is it. Once it is all together, I'll post a photo. One picture is
>worth a thousand poetic phrases. The base and standups are all 1" alloy,
>the shaft is 1" SS round stock. It is electrically isolated (read that
>"insulating belt driven"), and the disc is 1" x12" G11. Last time I looked
>at the design, the electrodes were to present a hemispherical, 1/2" face
>to each other -- set at an appropriately calculated angle to allow for the
>burn-off of early arc and/or late quenching to wear uniformly (I'm betting
>that part of the plan will just never work, what with windage and random
>heat transfer and magnetic field effects on the arc and all).
>At any rate, I cannot change his mind to down size the thing, so it fell
>to me to come up with a variable speed control for the 1 phase, 240v, 2 hp
>motor we have now, or a motor and control to suit whatever can get the job
>So, thanks for your input, I'll pass it on to the "team." You see, I am
>over 50 (one foot in the ground already and the other on uncertain
>footing), no longer in an "official" lab... so what do I know -- about
>anything -- in the face of the educated, under thirty crowd????
>Oh well, he is my retirement plan, so I guess I'll humor him ;-)
>Have a great day,
>Tesla list wrote:
>>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
>>If you need one in a hurry, you probably can't be too picky in what you pick
>>up used. Best bet is to check out Grainger-dot-com.
>>They have a very large number of universal motors / induction motors from
>>the fractional range up to the hundreds of HP.
>>Why do you need one between 2 and 5 hp for 15-25 kW. I've typically seen
>>less than 1HP universal motors used on 15-25kW sized ARSG.
>>Unless you are making a HUUGGGEEE rotor, than i think a 0.5-1.0HP motor
>> > Hello folks,
>> > Do any of you have a source for either a universal type AC motor of
>> > 2 and 5 hp, or a variable speed (chopper-type?) controller usable for a 2+
>> > hp induction motor? We need to have built and tested an ASRG for 15-25 kW
>> > by July 1st.
>> > I suppose a suitable sized, and cool-running DC motor (speed controllable)
>> > would work well enough too.
>> > We have the machining and structural aspects well enough in hand, but
>> > finding a large enough, variable speed motor has proven very difficult.
>> > We need to find one or the other asap.
>> > Thanks,
>> > Bill L.
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