Value of a *big-assed* Allis Chalmers 3 ph motor

Awl--
Recently I posted the availability of a 60-ton Bliss press, for which there seems to be no takers. So ahm thinkin of takin the motor!! Don't know the exact rating, but it is
BIG, proly around 700 lbs, w/ grease fittings. Bigger than most elevator motors I've seen.
Any re-sale value to this motor--before I bust my effing ass taking this thing down? Plus, I might not even have the satisfaction of running it, cuz I doubt if my rpc can handle it. Altho this motor itself would make one helluva an rpc!! Good idear? ---------------------------- Mr. P.V.'d formerly Droll Troll
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My last BF motor deal: GE 40hp never used, wax still on shaft...$50

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http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&itemu03502791 FACTORY FRESH BALDOR 60 HP ELECTRIC MOTOR 230/460, Winning bid: US $299.00
All other 60 hp motors, higher priced, were not sold.
Your motor seems to be well used, and not new like that baldor.
I would not touch these monsters. I would rather deal with smaller $300 items, such as my hydraulic pump that I asked about in this NG (sold for $305).
i
On Sat, 9 Apr 2005 10:44:07 -0400, Proctologically Violated

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Normal guys don't need a big motor. Industrial guys who need a big motor usually want a new one. I don't say you will never be able to sell it, but I doubt it. I would pass on this.
Why would a 60-ton press need a motor that big? The 60-ton press I owned had a 3hp motor.
GWE
Proctologically Violated wrote:

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Procto sez:
"> Plus, I might not even have the satisfaction of running it, cuz I doubt if

Robert sez:
Unless you have one helluva rpc, forget trying to start the monster.
Correct, it would make a great rpc in its own right - - 1) providing it runs on 220 VAC. 2) You could wire it adequately to your residential power drop (not likely) 3) Assuming you could meet 1 and 2 above, you could afford very high electric bills.
Bob Swinney

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I'm sure someone might point this out --- Assuming the motor is strapped for 240 VAC, a large induction motor might be started with the use of a Pony motor (the Rozen system). After starting, it would probably be possible to run the large motor on ordinary residential service (but certainly nowhere near code). If the large motor was say, 60 HP, the idling current to keep it spinning would be in the neighborhood of 10 HP or so. That's 7.5 kW. At nominal 10 cents a kilowatt-hour, that'd be 75 cents per hour just to keep it spinning, not counting the consumption of load motors.
Bob Swinney

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Robert Swinney wrote:

No, the problem is the reactive current would be huge. Somewhere around 75% of the rated load current, but at practically 0% lagging power factor. This would blow your main fuses/breakers. The only way you could do it would be with a totally HUGE phase correcting capacitor bank. I'm guessing the reactive current couldn't be less than about 80 Amps. Maybe with everything else in the house off, you could manage to do it. if you left it running for a couple of hours, the power company would come running with their snoopers to find out who is driving their phase correcting systems crazy with the huge lagging power factor.
Jon
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Hey Guys,
I forget who the OP was on this thing about the large motors, but my experience was this:
I got a really nice ( recently rewound) freebie wound rotor motor (has slip rings) 3 phase (of course) 20 HP 220Volt motor from an elevator (some-one mentioned elevators earlier). Hooked it all up, using the "Jim Rosen" spin-up method, then switched it "on". I have 200 amp fuses for the main panel, and 30 amp fuses for the RPC test rig. It popped the 30's immediately. Eventually had 60 Amp fuses, which held OK, but my Amprobe said the draw on two lines was something over 80 Amps. No way I could afford to continue using this at that rate, so I got rid of the 20 and went to a 7.5 squirrel cage. I forget exactly, but draw now is more like 20 Amps or so.
Take care.
Brian Lawson, Bothwell, Ontario. XXXXXXXXXXXXXXXXXXXXXXXXXXXX
wrote:

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Jon sez:
"> No, the problem is the reactive current would be huge. Somewhere around

Oooooppps! Right you are, Jon. I overlooked the fact that a 60 HP motor's idling current would be much greater than the idling current of a 10 HP motor. I had surmised the idling "draw" of a 60 HP motor to be in the neighborhood of 10 HP. WRONG I had not accounted for the fact that the motor would still take almost the same amount of magnetizing (excitation) current as if it was developing full HP. In a nutshell, the reason is that an unloaded induction motor has a poor power factor. For example, I read that a Design B squirrel-cage induction motor, at 10% of full load, has efficiency of 33% and a power factor of 28%.
Thanks for the correction.
Bob Swinney

Maybe with everything else in the house off, you could manage

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Bob --- Isnt it nice to have access to the thinking of guys like Jon!! It is guys like Jon that keep me reading this news group.
Jerry

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10-4 Good Buddy, 10-4!
Bob Swinney

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We toss large three phase motors often. We tossed a 20 HP and a 25 HP a couple of years ago. IIRC correctly I posted a notice here for them that they were free for the taking, but no response! We do keep a few smaller, newer motors, but after we have 1-2 of one HP and voltage any extra gets tossed. Older motors seem to have less value, I guess no one wants to deal with the weight. 3 phase motors are relatively cheap any way. Greg
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Geez, at least sell 'em to a scrap yard - especially these days with copper at $1.50/lb and iron uh, whatever it is ($20/ton? Motor's worth at least a few cents iron alone..). Loose copper wire you can expect like $0.50 to $1.00/lb. from them.
Tim
-- "California is the breakfast state: fruits, nuts and flakes." Website: http://webpages.charter.net/dawill/tmoranwms
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On the big jobs we often rent a roll off for the scrap iron so it does get recycled, we also have a scrap dumpster at the shop. No one here is willing to take the time to strip the copper from the motors. We do save copper scrap when it is easy! So when I said we toss them, we really don't just toss them! Greg
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willing
Ah, good :) I like saving money *and* entropy...
Tim
-- "California is the breakfast state: fruits, nuts and flakes." Website: http://webpages.charter.net/dawill/tmoranwms
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Appreciate the feedback, prices. I was going to make this My Very Last Stupid Act, but maybe I'll pass and do my Act on/with something else. I *still* want a big motor, tho.... :)
Yeah, the point about such a big motor on a press is interesting. I think, in this case, the flywheels are SO big, that considerable hp is needed to get them started. After that, rel. low hp would keep it going. Mebbe it's just a *really big* 3 hp motor!! ---------------------------- Mr. P.V.'d formerly Droll Troll

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You might look at the spec plate on the motor. It could be very large for several reasons. Old motors had much larger frames than modern motors. A good many years ago, I built a ripping saw with a 5 hp three phase motor. The motor was not new when I bought it and it was about the size of a big watermelon ( and painted green to boot. ). I think it was a 284 frame. Now you can get a 25 hp motor in a 284 frame. The saw acted as if it had a 25 hp motor. Never saw it slow down even when ripping wet cedar.
It might also be a low rpm motor which would mean a bigger frame. Currently a 15 hp 1180 rpm and a 25 hp 1760 rpm are both 284 frame motors.
Dan
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Newer motors are smaller compared to the old ones of same HP. From "Audels Electric Motors", 5th Ed:
"Electric motors can now operate at higher temperatures because of the development of insulation systems capable of handling temperature extremes. The trend in motors is for reduced size and weight. This causes more heat to be generated by the operation of the motor. This higher heat must be handled by the insulation system without allowing motor life to be reduced significantly. The future may see a change inasmuch as aluminum may be used as the winding wire and the motor size will have to be increased to handle the larger (physical) size conductors. This will probably create a motor with more durability.
The insulation system, once the weakest link in the moor, no longer limits the designer of industrial motors. Newer materials may well be developed to allow for even longer life and the reduction of heat generated by motor operation."
Generally speaking, if you find a motor with a fluted case, it is one of the newer motors with improved insulation. The flutes are there to increase the radiating surface because the motor will run much hotter than an old one of the same HP.
Bob Swinney

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Actually since EPAC 92 and NEMA Premium were instituted, electric motors operate at lower temperatures because the efficiency is higher. EPAC requires 25 hp motors to have an efficiency of about 92%. So a current manufacture 25 hp motor ought to be consuming about 1500 watts at the most when unloaded.
Dan
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Proctologically Violated wrote:

Does this motor have a commutator on it? A lot of these big, old presses, shears and such had motors with wound rotor resistance start systems or centrifugal resistance starting. They have a 16' shear at the metals supplier that I go to. They shut it off when they go to lunch, probably to prevent customers from chopping themselves in half. When they get back from lunch, they turn it back on and let it run the rest of the day. It must take 45 seconds, at the minimum, for the motor to bring the flywheel back up to speed. That one has an automatic resistance starting system. it would burn the motor up for sure if it was a standard induction motor.
Jon
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