new motor to tinker with...

Electric Motors and Controllers
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thunder   100 µW

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new motor to tinker with...

Post by thunder » Apr 05 2021 8:35pm

I happened to replace a 220V 3 ph smart motor and thought it was interesting enough to pass along. This has 3 magnets on the rotor and an 18 pole stator, a 4 inch long 1/2 inch diameter shaft with a D shape . It came off a 5 ton commercial air conditioner squirrel cage fan. These should be readily available form your buddy the HVAC guy since the computer is usually the part that goes out leaving the windings and rotor usable for "projects".
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Vbruun   100 W

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Re: new motor to tinker with...

Post by Vbruun » Apr 06 2021 4:38am

Seems powerful, but also heavy!

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everythingisawave   100 mW

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Re: new motor to tinker with...

Post by everythingisawave » Apr 06 2021 6:52am

thunder wrote:
Apr 05 2021 8:35pm
I happened to replace a 220V 3 ph smart motor and thought it was interesting enough to pass along. This has 3 magnets on the rotor and an 18 pole stator, a 4 inch long 1/2 inch diameter shaft with a D shape . It came off a 5 ton commercial air conditioner squirrel cage fan. These should be readily available form your buddy the HVAC guy since the computer is usually the part that goes out leaving the windings and rotor usable for "projects".
Very curious.. strange that it has only 3 magnets? If it has 6 teeth per phase I would expect more poles, at least an even number :?

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spinningmagnets   100 GW

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Re: new motor to tinker with...

Post by spinningmagnets » Apr 06 2021 7:39am

A section of metal can be formed that has two magnets of opposite orientation embedded at either end of it, and I suspect that is what's happening here. Three segments with three pole-pairs / six magnets.

thunder   100 µW

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Re: new motor to tinker with...

Post by thunder » Apr 06 2021 5:38pm

Very curious.. strange that it has only 3 magnets? If it has 6 teeth per phase I would expect more poles, at least an even number :?
[/quote]

I have a friend that does a lot of HVAC work and will see if he has any of these laying around and check what inside them. I thought it was funny there was 3 magnets on the rotor and its functioning as a 3 phase motor(3 wires going to the stator). That said I understand the 3 phase stator creates an even number of magnetic poles, dependent on the way it's wound

thunder   100 µW

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Re: new motor to tinker with...

Post by thunder » Apr 06 2021 8:38pm

Vbruun wrote:
Apr 06 2021 4:38am
Seems powerful, but also heavy!
16 lbs

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amberwolf   100 GW

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Re: new motor to tinker with...

Post by amberwolf » Apr 07 2021 2:06am

Consider that it only has to run at one speed, and only handle one specific loading, so it probably doesnt' need a lot of magnets for anything like precise position sensing; it just has to be able to startup from a stop and reach a set speed within some short amount of time, then maintain that for however long (including permanently, for those that run their circulation fans continously with the "fan always on" switch on the thermostat).

Weight doesn't really matter for it either, in it's fixed mounting on the roof or a concrete pad, etc. ;)


Also, cross linking these two threads since they're about the same basic motor:
viewtopic.php?f=30&t=96136

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