"Big" Electric Motor?

Ive nothing else to do right now so why not reply? If youve the motor allready set up on the compressor frame, why not ry it out? A repulsion induction motor is designed to start on load mine have brushes and a commutator and windings on the armature. as well as the normal field windings. your modern one might not. Also what about the power supply for it? plugging in a 5HP compressor into your domestic supply is asking for trouble. It sounds like its a factory type compressor. How many CFM is it designed to give at 90 psi? The start load will blow most main domestic fuses.But its the right one for the compressor. Dont be in a hurry to junk it. Its equivalent new one today is going to very expensive!!

Repulsion/induction motors draw significantly less starting current than capacitor start motors. Unless you want to run the compressor on 3-phase, I'd use the old motor.

Ned Simmons

If the bearings are in good condition and the motor runs, why not just keep it on the compressor? Repulsion-type motors were designed for compressors, pumps and similar hard to start loads, and since it probably has more iron and copper in it than an equilivent modern motor, there is a very good chance that it will run cooler and draw less current. I use a 1/2 hp Century repulsion-induction motor patented in 1915 on my lathe (9" South Bend) and, while it is about as big as a present-day 5 hp. motor, it runs barely warm even under the heaviest cuts.

Mike

Um, what do you want to do with what you bought? (the compressor)? If the motor runs, why not leave it as is?

i

Thanks for all the suggestion on using the "Big Motor". I answered an add on Craigslist.com for a free compressor, just get it out of my garage, no picture included. After a phone call and asking some questions, I'll take it I said. Well when seeing it in person, I almost backed out because it so big. This is a compressor you would see in a service station. I wanted to upgrade my air needs a bit but this might be over kill. But it was free. It's a 2 stage Air flow compressor with a 3 foot cooling coil mounted on the back. I was hoping to use a smaller motor to make this thing a bit smaller. But the giant runs, and it was running on a household current at it's previous location so I guess I'll use the huge motor. It isn't the stock motor because it has a piece of angle iron bolted to the deck that houses the compressor and the motor. The motor it self is bolted onto a 1/2 inches piece of steel plate

18"x24" . The shaft is 28 inches long, end to end. with the body of the motor 15" in diameter. Now I just have to figure out were to put this thing. The wife isn't to happy to see it sitting in the garage. Jerry

Good deal.Care to post a picture?

You can always build a doghouse for it, just make sure that it is ventilated and add a little source of heat there, like a 130v light bulb.

i

If it was running on 120 volts at the previous location the compressor must not require a full 5 hp because that would require drawing somewhat more than 30 amps from the circuit. That's not very likely.

Maybe the compressor originally used a smaller hp motor and that 5 hp one was put on just because it was handy. If it WILL run on 120 volts as is, you could measure the current draw and decide if a smaller motor could do the job.

Jeff

-- Jeffry Wisnia (W1BSV + Brass Rat '57 EE) The speed of light is 1.98*10^14 fathoms per fortnight.

"Derstine" wrote in news:kL2dncb-lpzogwrYnZ2dnUVZ snipped-for-privacy@comcast.com:

Put a cabinet around it - it'll help muffle the sound and camoflage it.

Here are some quick pictures

I put a 5 gallon gas can in each picture for reference scale

Looks pretty nice. I hope that it works. If not, you can always buy a new pump. They are not too expensive if you look in right places.

i

I've got one too.(also a century) Huge, heavy, and bulletproof. I was trying to think of a way to mount the tank on TOP of the compressor to be able to make use of it but gave up.

Hummmm...ah...why not simply use it? You dont have space for the motor? Doesnt it mount on the compressor?

Think it will use that much more electricity? Might want to put an amp meter on both of them and fire them up.

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Outside the garage, with a nice (cheap) leanto type shelter built over it. Out of sight, out of mind.

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Nice!!

Ah..I thought you said it was big?

Thats a great rig. And its got an aftercooler too!

Great score!

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Keep the motor and use it. If you buy a new one, it'll cost you big money and probably won't be half as good.

Chris

Btw....thats probably not 110vts, but 220. Might want to check the data plate closely. Id be surprised if that were actually 110vts

And yes..its a big motor. Which is a very GOOD thing.

Gunner

Political Correctness

A doctrine fostered by a delusional, illogical liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Oh HELL yes, keep it, save it, use it. If the bearings are good, and the insulation checks out OK, use it - as others have said, they really don't make them like that anymore.

Repulsion-start induction motors have excellent starting properties with a very low current inrush, and it handles voltage dips on start gracefully, making them perfect for residential use on smaller main breakers and very long feeds from the pole - go read page 17:

It is probably worth fixing if it has minor problems - I would make sure the start switch mechanism is free and works before powering it up the first time, once the motor gets up to speed it shorts out the windings on the rotor with a flyweight system - if it stays in repulsion too long it may overspeed...

Should have a local motor shop look and make sure the stator windings don't need a varnish "Dip and Bake".

If you really don't want it, there are a few things to do. You can call around to regional museums and see if they need one to restore a display, or repower some period equipment.

You could call A.O. Smith Motors, current owners of Century - they are still around and might have a museum.

-->--

Ahaaaaaa, A picture is worth a 1000 words. From the looks of it, the motor and compressor are much earlier than the tank and the pressure control switch. Not that it matters, Id say that the motor and compressor are from the 1930's to 40's. and the tank from the 60's to 70's. Also as I thought, its a brush start, with centrifugal throw out of the brushes when up to speed. the bearings will be plain, and when you unscrew the closing strips above the barings youll see felt threin. Probably dried out. So put some engine oil in there . There might also be a drain screw low down in the bearing area. All motors of this age need to be kept in the dry as the insulation varnish was not up to todays standard. outside in a leanto isnt safe enough, even with rcd s in the circuit, It also looks as tho it was all mounted onto the top of the later tank. Leave as is... Also clean out the valve in the tank inlet below the compressor switch, these do get all gummed up and then dont seat properly then back pressurise the line to the compressor. Whilst your at it check the valves in the compressor head. Take care not to damage the gaskets, as you probably wont find new replacements, and making up out of cornflake packets is a chore.# Nice one!! Isnt the throwaway society marvellous!!