Author Topic: Any ideas what this motor is?  (Read 2697 times)

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tanner0441

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Any ideas what this motor is?
« on: October 15, 2011, 06:53:47 PM »
Hi

Someone brought me a couple of three phase motors to test the other day.  The first one was a Crompton 1 horse 440 V.  I checked it for leakage and make sure it was star connected, then fed 110 V to it gave it a spin by hand and it ran up, swapped the wiring spun it by hand and away it went, then did the same thing on 240 V, I don't have 3 phase and did not want to go looking for capacitors.

The second one has 6 wires coming from it, it meters out like two bi phase transformers but all the wires are connected and measure 64 or 110 ohms. It is a Swiss motor and I could find nothing on the internet.  It is a well made motor, sealed case with fin cooling and no internal switches.  When connected to an isolating transformer ,sick and tired of resetting the clocks when I trip the RCD (gfci), and it hums but no amount of spinning by hand could get it to run up.

I wondered if it is part of a speed controller or braking system.  I think it will finish up in the bin.  Any ideas would be helpful..

Brian.


rossw

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Re: Any ideas what this motor is?
« Reply #1 on: October 15, 2011, 08:07:36 PM »
The second one has 6 wires coming from it, it meters out like two bi phase transformers but all the wires are connected and measure 64 or 110 ohms. It is a Swiss motor and I could find nothing on the internet.  It is a well made motor, sealed case with fin cooling and no internal switches.  When connected to an isolating transformer ,sick and tired of resetting the clocks when I trip the RCD (gfci), and it hums but no amount of spinning by hand could get it to run up.

My guess is it's a stepping type motor. Electronically comutated. Highly likely it'll require multiphase power drive.

The second diagram on this page is a 6-wire stepper that I think may be similar in function to what you have.
http://www.piclist.com/techref/io/stepper/wires.htm

ruddycrazy

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Re: Any ideas what this motor is?
« Reply #2 on: October 15, 2011, 08:24:38 PM »
If it is a 6 wire stepper then there will be 2 pairs of wires (ie 3) in common. The one that measured 1/2 the ohms will be the power wire. If all 6 wires show ohms then it won't be a stepper. Now when you turn the output shaft does it feel like it slightly cogs and goes in steps, then if so it will be a stepper. If the motor shaft turns freely with no notching then it could be a servo but that only a guess.

Cheers Bryan

ghurd

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Re: Any ideas what this motor is?
« Reply #3 on: October 15, 2011, 11:28:15 PM »
There are some PM servo drive motors something like a stepper motor.
Put a AC volt meter on the 110 ohm wires and give it a spin.

G-

PS- Here is one like I am talking about,

www.ghurd.info<<<-----Information on my Controller

tanner0441

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Re: Any ideas what this motor is?
« Reply #4 on: October 16, 2011, 05:29:05 AM »
Hi

Its not a stepper.  I have stripped it and it looks like a standard squirrel cage rotor. It meters out like two tapped transformers, but all the windings seem connected, it's only just over half horse, if I remember 0.45 Kw shaft output. The winding is not very heavy but there seems to be a lot of wire inside, and the back EMF really bites when I dropped my test wire from the transformer I was using to test it and caught it.

Brian.

ghurd

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Re: Any ideas what this motor is?
« Reply #5 on: October 16, 2011, 08:09:26 AM »
It sounds like Ross is correct.
(not all stepper motors have magnets)

Might be like Ross' example, except dia #3, 5 wire unipolar (it is not super uncommon for larger motors to have 2 joined common outputs).
Are there any 2 wires with 0 ohms?

Might be a 5 phase, if there is only one wire that reads 64 ohms to every other wire.
It would be a VERY expensive motor to replace, but not much demand for them.

Either way, after the wiring is figured out, it would be fun to cram it full of magnets and see what comes out.
G-
www.ghurd.info<<<-----Information on my Controller

tanner0441

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Re: Any ideas what this motor is?
« Reply #6 on: October 16, 2011, 01:31:24 PM »
Hi

It has 6 wires coming out and seems to be wound like two center tapped transformers, ie. 120 ohm across two wires with a center tap that reads 64 ohms from either leg, but there is 120 ohms between the two sets of windings.  It is meant to run on 440 V.  If it is going in the bin I will scrounge it.  I have enough 25mm by 10mm magnets at least 20 of them. It might be fun to get the rotor turned down or see if I can drill 25mm holes to hold the magnets and see if I can work out the way it's wound.

I just cleaned the plate off and it would appear to be two speed 1400 and 2400 RPM.

If I get chance I will try to have another look tomorrow.

Brian.

ghurd

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Re: Any ideas what this motor is?
« Reply #7 on: October 17, 2011, 04:33:41 AM »
or see if I can drill 25mm holes to hold the magnets

Do not set the magnets in holes in iron.
It shorts the flux.
G-
www.ghurd.info<<<-----Information on my Controller