Sealey Drill Motor - Electrical help

Electrical help requested

I have a 0.5 hp induction motor (240 volt) that was fitted to a Sealey drill press. Is it possible to reverse the D.O.R by swapping the wires over. Would like to use this motor to power a small vertical milling machine and it would make life simpler if it ran the other way. Steve

Edited By JasonB on 22/03/2015 07:45:11

Stephen, it may be possible, can't say without more information. Photos of motor, data plate and motor connections would help.

Dave

Edited By JasonB on 22/03/2015 07:45:32

Thanks Dave will try to post necessary info asap.

Steve

Edited By JasonB on 22/03/2015 07:45:49

To reverse a single phase motor you reverse the polarity of the start winding. The problem is in identifying the start winding! If the motor has a centrifugal switch, the winding attached to the switch is the start winding, just reverse the connections of the coil, and the motor will reverse. Likewise if you see four wires coming out of the motor at the terminal box, see if there is any information on the inside of the box cover. Sealey may be able to tell you. As has been said above however, some motors are often connected for single direction rotation and to find the ends of the start winding would involve cutting into the motor tail connections, not recommended unless you know what you are doing. It used to be easy when we had British Standards and the start winding was marked Z1 and Z2, but unfortunately we no longer live in the age of quality manufacture and universal compatibility.

Ho Hum

Phil

Have tried to upload pics of motor but have not succeeded yet. It doesnt help being away with work for two or three weeks at a time. Also my IT man(11 year old grandson) works out very expensive. Will keep trying< thanks for comments so far.

Steve

Hi steve,
Posting pictures on this forum is not as easy as on other forums. You first have to upload them to your albums. Here are links to some threads on the subject.

http://www.model-engineer.co.uk/forums/postings.asp?th=103028

**LINK**

**LINK**

Les.

Edited By Les Jones 1 on 03/04/2015 08:56:26

Hope these pics help and thanks for the posting help

Steve

Hi Steve,
From your pictures there only appears to be two wires coming from inside the motor.This could mean two things. One The windings and capacitor are connected togeter inside the motor. Two There are some wires connected to the back of the connection block. It may be posible to undo the screws holding the terminal block to see if there are wires connected to the back of the connection block. If you cannot do this remove the yellow wires that come out of the motor (Mark them so you know which is which.) Measure the resistance between the yellow wires. Measure the resistance between the terminals on the connectot block. I expect one of the readings to be between 2 and 15 ohms. The other will read open circuit. (It may read less than an open circuit very briefly if it is a winding in series with a capacitor.) If you do not see the brief reading then connect these two terminals to the mains via a low wattage filiment bulb. 15 to 40 watts.) If tha lamp does not light at all then the conections between the windings and the capacitor must be inside the motor. If you have any test equipment that can read capacitance then use this instead of connecting it to the mains via a lamp. If the connections are internal then the motor will need to be dismantled and you may even have to get into the end connections of the windings. As you do not fully understand motors then you will need someone to help you. Report back with the results of these tests.

Les.

Les I have now done what you said and the lamp did not light, so assume, as you say, the connections must be inside the motor. I shall seek a mechanical means of reversing DOR. Thank you all for your help

Steve

Edited By Stephen Fuller on 03/04/2015 16:07:56

I wonder if this motor can be reassembled with the shaft at the other end and if so will it still rotate in the original direction? Colin

Hi Steve,
Colin's suggestion is worth considering but it will probably require extending the wiring to the centrifugal switch. Also check that the axial alignment of the rotor and stator are still correct with the ends reversed.

Les.

Thanks for that suggestion Colin and Les but as the motor still runs nicely it is probably best if i stay outside it.

Steve