You are here:

Electric Motors/Old lathe motor


I have an old motor, the label reads 'Woods of Colchester' in the UK. 200/220 Volts, 3.8Amps. Cycles 50, phase 1, RPM-1400, 1/2hp, to B.S.S. 170/1926. Repulsion Induction Motor.

It was operating forward and reverse, the latter for screw cutting. It stopped operating in reverse, it was switched with a normal closed contact/switch one way for forward and the other way for reverse.
There are only 3 wires coming from the motor. Swapping the red and black, it still runs forward. I took it to a local motor repairer, they said it will not operate in reverse unless the brushes are physically moved 15 degrees the other way. This was tried, works fine, but it does not explain how it operated in reverse with only 3 wires. Do you have any information that may help me with this problem.

Tony  one thing to keep in mind,  many of those old repulsion induction motors are now antiques and often valuable,      

They are also horribly inefficient   but have tons of low end torque,

The above is very technical but it defines the three types of RI motors.

Without writing a book the above does the technical explaining,   

I guess I am trying to understand the question     the motor reversed prior to   now someone says the reversing is done with physically moving the brushes     does that sum it up?

above  last page   chart/graph  on right  three lead repulsion induction motor,  

The confusion  and I have never heard of a WOODS OF COLCHESTER   but some RI motors have windings internally that are actually wound as one set for one direction and one set for the other direction,  and while in one direction one set of windings is not energized,    

Check your control for burnt contacts,     or an intermittent or completely open wire somewhere  or a high resistance connection   that has become corroded   

If you cannot find the problem write me at my personal email  it is somewhat easier and we will figure it out,  but most likely it has two windings,  as the brushes did not shift with a handle or other mechanism before    I think that is where you are going?  

Electric Motors

All Answers

Answers by Expert:

Ask Experts




Three phase/ AC DC single phase motors, controls, any problems or failures, motor installation, performance issues, connections. All other electric motors/gearboxes/apparatus. Specialty repair concerns, obsolete motors and solutions. Other mechanical or specialty equipment. See my profile under Home/electrical at this site


30 plus years in the electrical motor and apparatus repair industry. VP level management of repair facilities, current owner of my own specialty repair and consulting firm.

EASA, IBEW [retired], other specialty organizations, Lubrication, Vibration EDI, Tribo-electric Councils

Currently fielding concerns at this site under "Home Electrical"

4 year technical, College level specific courses, EASA repair courses, vibration analysis electronic and electrical trade school.

©2017 All rights reserved.