Reversing a universal motor.
Reversing a universal motor.
(OP)
I have a 1.5 HP commutator motor running on 230V AC, I need to be able to reverse the rotation, can anyone point me to some data on this type of motor, or how I can carry out this modification. It is an old Metropolitan Vickers, ( type CKS 3014. 230/450 V. )
Thanks, Will.
Thanks, Will.





RE: Reversing a universal motor.
RE: Reversing a universal motor.
RE: Reversing a universal motor.
RE: Reversing a universal motor.
RE: Reversing a universal motor.
There are 4 wires coming from inside the motor, one pair is connected to the incoming phase wire, and the other pair to neuteral.
Don't know which ones to change. Tried swapping the incoming line wires around, of course with no result.
Can anyone enlighten me, or show me some good sites with a clear description of what to do, so I can enlighten myself.
Thanks, Will.
RE: Reversing a universal motor.
It could be a Schrage Commutator motor that has brush braces for RPM control/adjustment.
Regarding the connection and speed reversal, visit
http://www.electricmotorwarehouse.com/aosmith/C_U_CONNECT.PDF
to see what may be involved. It would be more appropriate to obtain information from the motor manufacturer.
RE: Reversing a universal motor.
The motor is old, and I'm not sure that this company exists anymore. Nameplate reads:-
Metropolitan Vickers,
( Type CKS 3014 )
230 / 450 Volts
1450 RPM
Running on 230 V Ac, 50Hertz.
( Just realised I gave this info way back at the beginning )
The internal wiring from the junction box is all black this doesn't help at all.
The brushes are all perpendicular.
Thanks everyone,
Will.
RE: Reversing a universal motor.
The neutral position for the brushes coincides with the axial centre line of the main poles i.e. the stationary windings mounted on laminated poles around the bore of the motor housing. As you have 4 brush positions, you should have a 4 pole motor i.e. there are 4 main poles.
Incidentally larger DC motors (supplied with DC), particularly those meant to be reversible, usually have the brushes in the neutral position and instead have additional windings (interpoles) placed between the main poles, and possibly even compensating windings mounted in the pole face of the main poles, to reduce the sparking. I doubt very much that your universal motor will have either interpoles or compensating windings. Relying on the brush position shifting has two disadvantages:
1. the ideal position for the brushes depends on motor current - higher loads ideally require a larger shift, so some compromise may be required if the load is variable.
2. if the motor is reversed, or changes from motoring to generating, the brush position must be shifted to the opposite side of the neutral position.
Hence the technique is only used on relatively small motors. You may have to experiment with brush position to minimize sparking at the brushes.
To achieve reversal then, you should find that every other brush holder is connected together. If you shift the connections around by 90 degrees (ensuring that opposite brush holders are still connected to the same point), and if necessary move the brush positions to minimize sparking as previously described, you should be in business. You may want to experiment with on reduced voltage at first, ac or dc.
I hope this all makes sense. Metropolitan Vickers was an old UK company by the way, they disappeared nearly 40 years ago so you do have an old machine!