Author Topic: 230v 70s motor wiring  (Read 836 times)

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Offline lightspeedTopic starter

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230v 70s motor wiring
« on: September 03, 2020, 01:59:40 pm »
I have an old compressor I rescued from the trashcan and was looking to test it however while the name plate says  "230v" I see an incoming white and black wire on the pressure switch. Circa 1976.

Thats leading me to believe its actually 120v. Anyone experience this? Wiring diagram seems to contradict voltage rating. Will post pics shortly.
 

Offline WattsThat

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Re: 230v 70s motor wiring
« Reply #1 on: September 03, 2020, 02:09:39 pm »
The wire color means absolutely nothing.

If it more than 1 HP,  I’d lean more towards thinking it’s 230 volt. The starting cap rated voltage may be another clue. You might be lucky and find a connection diagram inside the conduit box or capacitor cover.
 

Offline drussell

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Re: 230v 70s motor wiring
« Reply #2 on: September 03, 2020, 02:16:43 pm »
Indeed, the wire colors are irrelevant. 

Many smaller motors, though, can be wired for either 120 or 230v depending on how the windings are connected in the junction box terminal, usually accessible under a small cover with a couple screws.

The data plate will generally indicate this, though, so if it just says 230v it is probably 230v only. 

Perhaps you could post a photo of the data plate and a photo of the motor itself so we could advise further?
 

Offline Stray Electron

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Re: 230v 70s motor wiring
« Reply #3 on: September 03, 2020, 02:22:00 pm »
  Anything 1/2 HP or less is probably 110VAC only. Anything over 1 1/2 HP  is probably 220VAC only.   Between those ranges it's probably 110 or 220 VAC motor depending on the straps in the junction box.  If there's a box on it open it up and there should be a label telling how to jump it for each voltage.  Keep in mind that manufacturers were lying like all Hell about motor power in those days and it's HP rating is probably greatly exaggerated.   What type power plug is on it?

  You should be able to look up the make and model number and find a manual for compressor and/or the motor and it should tell you everything that you need to know.

   You should be very wary of running on old compressor that you don't know anything about!  Many of those old tanks were never drained properly and water collected in them so they are rusted out and can easily explode if you put much pressure in them.
 


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