CAN A 1PHASE MOTOR BE REVERSED 1

[jeb3558]

The motor is a single phase 110/220 1 1/2 hp 60hz it has 4 leads out of it.It was mounted on a air compresor turned around with a added plate of steel to run the compresor in the correct rotaion.I would like to put the back on the original location, but can't get the direction to change like a 3phase whould.Its an old unit and was a gift.The leads are marked 1 2 3 4 for 110 line 1 connets to 1 and 2 line2 to 3 and 4 for 220 2and3 connect together line1 to 1 line 2 to 4 Thanks for any help Jeb

 

[rbulsara]

See this links..

http://www.usmotors.com/Connections/108324.pdf

http://www.electricmotorwarehouse.com/motor_connection_diagrams.htm

 

[motorsdirect]

hi.
seeing that this is a dual voltage winding..it sounds like you are wiring it in series and parallel and its not obvious whats going on.
if you still havent got it working, you can always leave a reply...
Jeff
jeff@motors-direct.co.uk

http://www.motors-direct.co.uk

 

[aolalde]

jeb3558

There are many designs for single-phase motors and detail knowledge of the construction is required to attempt modifications. You should regularly provide the entire nameplate data available.
As this motor moves a compressor I will assume it is a split phase capacitor starting motor. For that type of motor you need to reverse the polarity of the starting winding only, but this will be an internal connection.
The starting or auxiliary winding must be connected in series with the capacitor and a disconnection switch, all attached in parallel to a leg of the main winding , this way it always works with 110 volts, in spite of the external connection. You need to locate the two leads of that winding and reverse them in order to reverse the motor rotation.

 

[SteveKW]

To add a bit more information to Aolades explanation of finding the start leads you will need to look at what is connected to the pairs of leads 1&3 and 2&4. One of those sets will have an extra wire to each lead that are of a smaller wire gauge and/or different color wire. This would be your start windings. If your motor has a capacitor on it you can confirm you have the two start leads by putting an ohm meter across them. This would show the changing of resistance as the capacitor charges. Swapping those two wires will reverse the motor!

The third & fourth diagrams here are excellent in showing how your motor is connected. It only lacks the start capacitor in series with the start switch. On that diagram you would be swapping the red & blue leads. Also 1A would be your 1&3 and 1B is 2&4.

http://www.electrical-contractor.net/ubb/Forum15/HTML/000086.html

 

[SteveKW]

Looks like the forum software is not perfect just yet.
Cut and paste the link.

http://www.electrical-contractor.net/ubb/Forum15/HTML/000086.html

 

[Marke]

Hello jeb3558

This type of connection is common for shaded pole type motors, but at 1/2 horspower, this is not likely.

If it is not a shaded pole motor, then it could also be a universal motor (with brushes) again not likely if it is for continuous running.

Logic would suggest that it is an induction motor, and if it is, there must be a start winding.
There are a number of configurations for the connection of the start winding in a single phase induction motor, some of them are represented here :

http://www.lmphotonics.com/single_phase_m.htm

In order to reverse the rotation of a single phase induction motor, you need to identify the start winding and reverse its connection. The four connections that you have identified so far, are connections to two run windings, each wound for 110 volts. You connect them in parallel for 110 volt operation and in series for 230 volt operation. Thes two windings are both run windings, neither is a start winding so do not reverse either winding relative to the other.
I suspect that on of these run windings, will have an internally connected start winding in parallel. The start winding may have a series capacitor and may also have a series switch which operates when the motor reaches full speed. If there is no capacitor, then there must be a switch.
You will need to partially dismantle the motor and trace the connections that go to terminals 1 2 3 and 4 and look for the parallel winding with a series component (capacitor and/or switch). Once you have located this winding, reverse its connections, and the motor will run in reverse.

Best regards,

Mark Empson

http://www.lmphotonics.com

 

[SteveKW]

Hey Mark

I have never run across a "capacitor star/run" motor as described by #4 on your link.

Can you suggest any reference material as to its theory and application? Possibly a web site?

Regards,
Steve.

 

[Marke]

Hi Steve

I came across alot of these configuration in small airconditioning units of Asian origin ome years ago when I was building single phase soft starters. I have'nt seen technical reference to them of late, but they were quite small machines.
If I find further reference, I will post it.
Best regards,

Mark Empson

http://www.lmphotonics.com