Reversing an electric motor

[John MCParticipant @johnmc39344]

[John MCParticipant @johnmc39344]

Morning all. I need to reverse a small (240v, 1/10hp) motor. The motor has 3 wires and a permanently connected capacitor. The wiring diagram for the motor tells me it is non-reversible without dismantling. So I googled the problem and found a video that suggests that all I need do is remove the rotor and replace the opposite way around. Is it really that simple?

John

[Ian S CParticipant @iansc]

Yep John, that's it.

Ian S C

[roy entwistleParticipant @royentwistle24699]

If your going to remove and reverse the rotor why not just turn the motor round ?

Roy

[john fletcher 1Participant @johnfletcher1]

If the motor is permanent capacitor without a centrifugal switch ? if so, yes. If it has a centrifugal switch then you would have to some how extend the wires which are connected to the C/switch to the other end. On some make of motor that is possible ,not easy though.John

[John MCParticipant @johnmc39344]

Many thanks for the replies. I don't think turning the motor over will change the direction of rotation! I'll dismantle the motor and do the necessary next week and report back.

John

[Ian S CParticipant @iansc]

At that size i imagine that it is a shaded pole motor, if so, all it takes is the time to undo the 2 to 4 through bolts that hold the end covers in place, pull the armature and turn it around, and bolt up again.The motor will still turn in the same direction, just that the shaft will stick out the other end.

Ian S C

[EmgeeParticipant @emgee]

Hi John

You may like to try this first, Diagram 15 shows how to reverse a 3 wire induction motor with capacitor start & run..

**LINK**

Emgee

[John MCParticipant @johnmc39344]

Kudos to Emgee, the link was just what was wanted, motor now running in the right direction.

Now I have had a good look at the motor, reversing the position of the rotor would not be a good idea, the innards are not symmetrical.

Once again again, thanks Emgee.

John

[EmgeeParticipant @emgee]

JohnMC

I don't know your application for the motor but if you want to be able to run in either direction all you need is a SP changeover switch (SPDT) With centre OFF, The circuit is on the same site as the drawing.

Emgee

Edited By Emgee on 09/10/2017 19:13:07

Edited By Emgee on 09/10/2017 19:14:04

[John MCParticipant @johnmc39344]

Hi Emgee, the motor is driving a G H Thomas designed sensitive drilling machine. Originally the motor was mounted so the belt could be crossed to get the correct rotation. I have now mounted it in the conventional mounting position for a small drilling machine hence the need to reverse the direction of rotation.

I built the machine when GHT described it in ME, 1983-4? The motor came from K R Whiston, remember them?

The drill could do with a little more power, 88w at the moment, starting torque could be better, once up to speed a 1/16" through steel is OK. Been looking for a more powerful motor, no luck yet.

John

[Author]

Posts