Repairing smaller 400V HVAC flu motor with open wire

[DAVEISGREAT]

Picked up a dead 400V HVAC flu motor at a flea market.  At 120V no current would flow so I took took it apart and found an open very fine copper wire.  Soldered open wire, motor now passes current, and will move the shaft a fraction then quit,, at 120v.  Also, tried manually spinning motor to give it jump start,, no go.  I do not need the motor since I only have 120 and 230V.  It has value and would like to sell,, but want to make sure it is working properly.  Thought about connecting 220V but motor's power input only has 2 wires so I do not know how to hook up 220V(120V,, simple blue and red).  The capacitor tests good.  Attached is wiring diagram.  Any advice how to test/wire motor for proper function greatly appreciated.

[langwadt]

a broken motor you found at a flea market, what value does it have?

[DAVEISGREAT]

Here's clearer picture of wiring.  Looks like wiring was backwards as found,, now I'm even more confused. 

Working,, has value of course.  minimum, a spare when your heat or AC goes down.  As long as the motor's windings are not burnt, motors can be quite robust lasting decades. 

Besides not knowing how to properly wire motor for test, also do not understand the stamping on motor "asynchronous single phase"...

[Jwillis]

That's a 460V motor. At 120V it probably doesn't have enough torque to turn over or keep running. Might at 220V. 
The connection of the blue and red wire to AC doesn't matter.
 

[Zero999]

It might turn at 240V, but will be weak and might even draw too much current and overheat.  You need a step-up transformer to get it to work properly, which will cost more than the motor itself. My advice is to count your losses and junk it.

[CaptDon]

Looks like that motor has had a rough life. If it is a bronze bushing motor I would junk it now as the bushings will probably be just about shot anyway. I have never encountered a 460VAC rated flue motor and can't imagine it has much use to anyone except those with industrial 3-phase wiring where this motor would sit across any 2 of the 3 phases, and if so, they would never pay for a questionable used motor. Here in the states I think the shift was from 440V.A.C. to nominal 480V.A.C. with that motor being 460 rated have I missed something? Surprised to see a 450vac rated capacitor on a 460vac rated motor?

[Zero999]

a broken motor you found at a flea market, what value does it have?

I'm certainly not judging the original poster for buying junk. I've done it myself in the past and I'm sure many others here have. It's part of the learning curve. The best thing to do is dispose of it, hopefully getting some money back if possible and learning from the experience.

[DAVEISGREAT]

Hope you all understand english: 

I have repaired the motor,,
Motor/blade spins freely like new $500 motor,,
My question is,, I don't understand how to wire motor to 220V for a QUICK test? As found, looks like leads are wrong,, per diagram appears capacitor leads should go to motor/vice versa?):

I have a shiny new 220V bare extension cord on hand.  Motor only has two power leads.  Is it safe to join the 220V cord's 2 hot 120V wires then connect joined cords and neutral to motor's two AC wires?

[Zero999]

The motor cannot be wired for 220V. The fact you've repaired it, does not change the fact that it is the wrong motor.

[DAVEISGREAT]

It might turn at 240V, but will be weak and might even draw too much current and overheat..

Do you think motor would withstand a 1 second test at 220V?

UPDATE:  I switched the leads per diagram.  Flash on/off test,, motor has audible hum at 120V does not spin fan.   As mentioned before,,  as found wiring configuration had same motor hum, plus moved the fan blade 1 inch,, what colors do you think the power leads are?  Maybe the diagram is wrong and as found wiring is correct (diagram could be for a single phase asynchronous motor per label), not for 3-phase wiring which this motor is?  Just call me a confused knob

[DAVEISGREAT]

Is it safe to join the 220V cord's 2 hot 120V wires then connect joined cords and neutral to motor's two AC wires?

Not in my case!!  So in as found motor wiring configuration, I shorted both 120V hot wires at the bare end of a 240V plug together and connected both live wires to one motor winding, then connected plug's neutral wire to other motor wire.  Then I plugged plug into 240 outlet ---> LOUD POP THAT THANKFULLFULLY TRIPPED THE 240v BREAKER AND ALSO TRIPPED THE 150A 100A HOUSE BREAKER !!  Now I know how ElectroBOOM must feel.  Can someone explain what just happened (please refrain from lecturing lucky to be alive)?

[langwadt]

Is it safe to join the 220V cord's 2 hot 120V wires then connect joined cords and neutral to motor's two AC wires?

Not in my case!!  So in as found motor wiring configuration, I shorted both 120V hot wires at the bare end of a 240V plug together and connected both live wires to one motor winding, then connected plug's neutral wire to other motor wire.  Then I plugged plug into 240 outlet ---> LOUD POP THAT THANKFULLFULLY TRIPPED THE 240v BREAKER AND ALSO TRIPPED THE 150A HOUSE BREAKER !!  Now I know how ElectroBOOM must feel.  Can someone explain what just happened (please refrain from lecturing lucky to be alive)?

put down the wires and do some reading before you kill yourself or someone else, you seem to be missing the most fundamental understanding of how 120V/240V mains works

[Gregg]

I fully agree with Langwadt. 
First thing you need to do is figure out what is wrong here: "I shorted both 120V hot wires at the bare end of a 240V plug together"

[DAVEISGREAT]

For the 250V test, should have wired the two hot 120V leads to the two motor leads.   Double Doh. 

What should I do with the plugs ground wire?  If ignored does current have a path?  If no path, ground it to motor -help?

[vk6zgo]

Hope you all understand english: 

I have repaired the motor,,
Motor/blade spins freely like new $500 motor,,
My question is,, I don't understand how to wire motor to 220V for a QUICK test? As found, looks like leads are wrong,, per diagram appears capacitor leads should go to motor/vice versa?):

I have a shiny new 220V bare extension cord on hand.  Motor only has two power leads.  Is it safe to join the 220V cord's 2 hot 120V wires then connect joined cords and neutral to motor's two AC wires?

NO! in the NA system those two "hot" 120v wires are at 240v potential with respect to each other.
Connect them together & you will see a big flash & your Mains circuit breaker will trip.
If you plug the extension lead into your 240v power outlet you should be able to measure 240v across the two "hots".

If I was testing your motor with the single phase  230v (nominal) Australian system, I would probably "take the chance" & connect its two AC wires between Active (hot) & Neutral, as the latter is connected to ground at the entry point into the building, &  in any case, even with a wrong selection of connections there is probably little chance that any of the accessible metal parts are connected to either side of the mains connection.
It would probably be OK with a motor designed for 400v, but I have zero experience of that system.

[Jwillis]

North America has split phase. Connecting two 120V to make 240v off of one phase will blow the breaker. Think of split phase as a centre tapped transformer with 3 terminals. 120V-0-120V.
To get 240V the 2 120V live from each phase without the common from either makes 240V. Just like a centre tapped transformer. that has  12V (first tap)  0V(centre tap) 12V (last tap) the centre tap is Common. When you connect the to out taps it makes 24V.

If you don't understand this. STOP NOW! Before you hurt yourself or burn your house down.

[DAVEISGREAT]

If I was testing your motor with the single phase  230v (nominal) Australian system, I would probably "take the chance" & connect its two AC wires between Active (hot) & Neutral, as the latter is connected to ground at the entry point into the building, &  in any case, even with a wrong selection of connections there is probably little chance that any of the accessible metal parts are connected to either side of the mains connection.
It would probably be OK with a motor designed for 400v, but I have zero experience of that system.

Do you think if two motor leads are connected to two hot 120V leads and plug's ground is left open motor will draw proper current?

[DAVEISGREAT]

To get 240V the 2 120V live from each phase without the common from either makes 240V. Just like a centre tapped transformer. that has  12V (first tap)  0V(centre tap) 12V (last tap) the centre tap is Common. When you connect the to out taps it makes 24V.

Plug and outlet are 240V so connecting the two hot leads separately to the two motor leads, leaving plug's ground open should send 240V to motor without popping breaker this time, if I understand correctly?

[Jwillis]

Please be careful. I had a colleague that was highly experience with high voltage equipment and wiring. One slip up and he died hours later after severely burning himself. Not a nice way to go or to have to remember.
A 240V outlet can have 120V  0Vcommon  120V   plus a ground for a total of 4 terminals (for a dryer is an example) Or it can have 3 terminals 2 120V one ground but no common (electric stove or welder).
Before you start make sure that the coil of the motor is not shorted to the body or rotor, A simple continuity check would work. I also suggest a switch between the motor and power. Secure the motor so you don't have to hold it. If the motor trips the breaker,  This would indicate that a short is in the coil. Then it'd best to dispose of it.
Again. Please be careful.

[DAVEISGREAT]

Thank you.  Motor has no shorts and I will add a switch as you suggest, along with a resettable fuse, and try in the morning in case of a black-out.

[soldar]

Here's clearer picture of wiring.  Looks like wiring was backwards as found,, now I'm even more confused. 

Working,, has value of course.  minimum, a spare when your heat or AC goes down.  As long as the motor's windings are not burnt, motors can be quite robust lasting decades. 

Besides not knowing how to properly wire motor for test, also do not understand the stamping on motor "asynchronous single phase"...

Do you understand "460 V"?

[CaptDon]

Question, the motor carries a 460 volt rating. Was that a typical rating for the old U.S. 440 V.A.C.? Since the U.S. has now chosen standards of 120, 208, 240, 277, 480. The 460 would seem a bit odd today. At G.E. in Erie Pa. we also had some 550vac and 600vac circuits. An engineer had to be very careful about connecting to the mains. We had equipment destroyed by the oddball 120 / 120 / 208 orange wire 'wild leg' 240vac tapped delta where one side of the delta is center tapped to get 120-0-120 or 240 as single phase. Sadly an electrician mistake put 208 on our lab 120vac receptacles. I worked around a really stupid implementation at a central Pennsylvania factory, 13.2KV 3 phase ran across the parking lot on poles and when it reached the roof of a particular building it was supported 2 feet above the roof for about 20 feet of distance and you could walk right into it!!! I have no idea how it functioned when the snow covered it?? Amazing no one was ever killed, even by coming into contact with the snow!!

[Zero999]

Use a small control transformer run in reverse. There appear to be plenty of units available with a 460V primary and 110V secondary. Running on 120V is no problem because it'll have extra turns to account for the volt drop, under load.

Here's one I found on eBay, but 50VA is a bit small for continuos operation.
https://www.ebay.co.uk/itm/184160007031

Here's a brand new one, which would be my recommendation.
https://us.rs-online.com/product/mgm-transformer-company/m22427/73662402/

[DAVEISGREAT]

Placed both hot leads across two motor leads,, with protective inline fuse and inline microwave switch(always off. as a kill switch).  With motor secured,, used a broom handle to momentarily depress switch for two or three seconds.  Unfortunately, similar motor hum, little if any rotation.  Mercifully, no million amp short!

Plan B:  I do have a 120V to 240V transformer rated at 500W .  Would it be possible to wire 220V into T's 120V side to  briefly get 440V output, then test motor start-up?

UPDATE:  Zero999 just noticed your post.  Like your similar, better idea but don't want to spend that much.  You think plan B is useable option?

[pcprogrammer]

Plan B is not a good idea. See https://www.eevblog.com/forum/chat/hv-transformer-dude-almost-terminating-himself-and-the-house-cat!/

It probably won't explode like what he used, but better safe then sorry. You will melt your transformer when you input double the nominal voltage.

Edit: The motor most likely has two windings. The main winding that is fed directly from the mains and an auxiliary winding that is fed via the capacitor to get a phase shift between the two windings. Make sure the capacitor is connected when you apply the voltage. Internally the mains wires will be connected to both windings and the capacitor will be in series with one of them.