Right on, Brian ! Some 2-speed induction motors are classed as "constant torque"; others are classed "constant horsepower". All of them utilize stator windings in which the number of poles is changed, usually 2 pole and 4 pole. Star-delta and delta-star configurations account for the constant HP and/or constant torque designs.
SNIP
Hey Wes,
Ummmm....not really. I'm assuming that the discussion here is about squirrel-cage types. A 2-speed motor is just that. And star-delta is a method of limiting start-up currents, or rather, reducing run-speed current, and is not a "speed changing" scheme. The motor wants to run at its synchronous speed. Many motors run star only, or delta only, depending on the application. The field windings are the same for either one.
2-speed on the other hand is just that, using two different sets of field windings, commonly to provide a 4:1 ratio. For most I've seen the available torque is reduced on the slower speed, unless it is a "special purpose" type.
Lots of 2-speed motors are wound-rotor, and therefore can be used as universal. These can have variable speed, rather than just 2-speed, but often are set up to operate as just 2-speed.
Use two contactors on the output of the reversing contactor or drum switch -- with the two contactors controlled by a form C toggle switch. Ideally, you want a switch which will force a pause while switching from one to the other, so you don't wind up powering both windings at the same time. I would use one of the pull-to-unlock military arming toggle switches for the selection of speed.
One low voltage switch for the speed selection. You can use a full drum switch for the forward/reverse switch -- or to control the reversing contactor (which probably is a latching style).
Thanks for asking. We did go to see the Hoover Dam, in fact on Christmas Day!! And while there were no tours available due to the Holiday, there was a lotta lotta lotta people doing what we were doing too !!! I have been at THE Dam a couple of times before, but my new daughter-in-law had not and she was amazed, mostly at the sheer drop on the "dry" side, although at present it's a bit hard to tell which "side" that is due to the Lake Mead water levels at the dam and as far as you can see being about 150 feet below "normal". And WOWWWW!!! that's a LOTTA water, or not water in this case.
I was most interested to see the completed new bridge, only to find it more interesting in that it is not complete yet, and so the means and methods of construction are readily visible, albeit from about 1/4 mile distant. Ummmm...that's not quite true, in that the "old road" to the west side of THE Dam allllmmmmmooooossstttt does a tight U-turn right under one span of the new bridge. One thing for sure, it will certainly speed up the "thru" traffic in the area, as now there is a "9/11" security inspection on the approaches that slows down traffic as much as the "gawkers" do on the very winding existing road.
Vegas was a Christmas Present for the kids, so Dad here was picking up the whole shot except the one-arm (now button pusher) bandits. 4 bucks for a coffee in Vegas was a bit much. So I was paying over 45 bucks for breakfasts and minimum $150 plus tip for dinners for the 4 of us. That's OK on a one time, but 5 days worth is getting expensive for this old retiree. I've got better things to spend my money on!! Lotsa things that were complimentary the last time we were there are now a profit maker, as the Vegas 2008 income was down 12% over 2007, and
2009 probably wasn't much better. And you can't walk down "the strip" at any time that some greasy looking group isn't handing out call-girl cards, most of which end up on the sidewalks. The city should charge them for clean-ups!! And we had expected to take in a few "shows", but the prices are as Steve B. suggested in his pre-Xmas email advice. Seemed to run about $ 130 per head, and I balked at that and we didn't see any. And long line-ups for almost everything, and my knees are pretty good, but not that pretty good to stand in any line for an hour or more.
We had nice rooms at Bally's though. That I would recommend to anyone going. Ask for a room with a "Strip view".
So, if it was the first time I had been there, I would say "I've been to Vegas twice. The first time, and the last time!!" No plans to go again. Maybe do Carlsbad next time.
Why don't you go BUY one? You are, after all, going to sell this to someone at a nice profit and probably, at best, paid scrap metal price for the rest.
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