RE: Need a variable-speed 2hp or greater AC motor for serious gap drive

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "brianb by way of Terry Fritz <teslalist-at-qwest-dot-net>" <brianb-at-antelecom-dot-net>

And they usually spin at under 600rpm...

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, June 04, 2003 9:56 AM
To: tesla-at-pupman-dot-com
Subject: 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.

Nick A


 >From: "Tesla list" <tesla-at-pupman-dot-com>
 >To: tesla-at-pupman-dot-com
 >Subject: Re: Need a variable-speed 2hp or greater AC motor for serious
 >gap drive
 >Date: Mon, 02 Jun 2003 06:33:03 -0600
 >
 >Original poster: "W.R. Langston by way of Terry Fritz
 ><teslalist-at-qwest-dot-net>" <blangsto-at-iwvisp-dot-com>
 >
 >Dan,
 >
 >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
 >done.
 >
 >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,
 >Bill L.
 >
 >Tesla list wrote:
 >
 >>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
 >><dhmccauley-at-spacecatlighting-dot-com>
 >>
 >>
 >>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
 >>would suffice.
 >>
 >>Dan
 >>
 >>
 >> > Hello folks,
 >> >
 >> > Do any of you have a source for either a universal type AC motor of
 >>between
 >> > 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.
 >> >
 >> >