AC 230 volt motor won't run, but 120 volt it will

Thread Starter

Dustys

Joined Mar 12, 2014
8
New motor out the box prewired with pig tail won't run on 230 volts, Check wiring on motor a ok. check thermo switch a ok. Check cap uf 800 and check model number on line came back with 120 volt cap. So could this be why it won't run on 230 volts. I put on a jumper and plug it in 120 volts and it ran. Never had one like this before!:eek:
 

#12

Joined Nov 30, 2010
18,224
It must be a 120 volt motor. I'm surprised it didn't just start smoking or explode the capacitor.
 

MaxHeadRoom

Joined Jul 18, 2013
28,702
Do you have any way of checking the current? Clamp meter on etc.
In any case the 120v cap is low value even for 120v supply?
Even if the cap were a problem on 240, the run winding should pass current and be evident by a hum or blow the breaker etc?
Max.
 

Thread Starter

Dustys

Joined Mar 12, 2014
8
When the motor is wired for 230 Volts and put mult meter on it show line open and no amp draw. With 120 volt leads on I do pick up resistance and amp draw is in normal on 120 volts
 

MaxHeadRoom

Joined Jul 18, 2013
28,702
Wrong hook up somewhere!
Check resistance across the line, when wired correctly it should show low resistance.
Where did you get the 230v diag from?
Max.
 

Thread Starter

Dustys

Joined Mar 12, 2014
8
Motor came pre wired with pig tail to be install in a controller for a grain elevator. Wire diag where located on the side of motor. I would post them but have not figure out how to do that yet.
 

Thread Starter

Dustys

Joined Mar 12, 2014
8
Check voltage at control box witch has a 230 coil that control all the safety a-ok and tested pig tail feeds at the motor. There three other motor on the system all setting on 230 volts all working fine, and this one work only on 120 volts.
 

#12

Joined Nov 30, 2010
18,224
You're back to, "read the diagram, find the error". Especially look for what Max said..a missing jumper.

Either your motor is running with only one winding carrying the 120V current or it's a mis-wire.
In 120 mode, 2 coils are in parallel, but they would be in series for 240V.
If one coil is open, it will stop all the current in 240V mode but one of the windings will still work in 120V mode.
Measure the ohms of each winding and see it they are all good.
 
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