CAN A 1PHASE MOTOR BE REVERSED
CAN A 1PHASE MOTOR BE REVERSED
(OP)
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





RE: CAN A 1PHASE MOTOR BE REVERSED
http://www.usmotors.com/Connections/108324.pdf
http://www.electricmotorwarehouse.com/motor_connection_diagrams.htm
RE: CAN A 1PHASE MOTOR BE REVERSED
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
www.motors-direct.co.uk
RE: CAN A 1PHASE MOTOR BE REVERSED
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.
RE: CAN A 1PHASE MOTOR BE REVERSED
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
RE: CAN A 1PHASE MOTOR BE REVERSED
Cut and paste the link.
http://www.electrical-contractor.net/ubb/Forum15/HTML/000086.html
RE: CAN A 1PHASE MOTOR BE REVERSED
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
RE: CAN A 1PHASE MOTOR BE REVERSED
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.
RE: CAN A 1PHASE MOTOR BE REVERSED
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