Thread: Spindle motor rewind
Very interesting John, Just goes to show with knowledge and patience a lot can be achieved ..Clive
Brilliant, well done. I don,t suppose that you want to rewind my HF (1000hz, 55volt) to 400hz 230volt), for a (small) bag of gold of course. This is a serious enquiry as I too have been told that it is not possible. G.
There are motor design programs out there but they are very expensive, need to find a friendly face in one of the universities. I tried a couple of re-winders for info but they really don't want to know about anything non standard.
Modifying an existing motor should not be too difficult if you accept that the manufacturer got it right with respect to flux densities in the stator (ampere turns in old money).
This something I found somewhere on the net.
Rewinding for a change in voltage
If a 220 volt motor is to be rewound to operate on 440 volts, use twice as many turns on each coil and one-half the circular-mills area of wire. In other words, if 40 turns of NO. 17 wire were used on the original motor, 80 turns of NO. 20 should be used on the new motor
Some motors rated for 230 volts will not handle the load on 208 volts if loaded to the maximum. The turns must be reduced to the ratio of the voltage change. As an example, 230-volt motor has 40 turns: 230/208 = 1.1, 40 turns/1.1 = 36 turns. If there is enough room, the next larger wire size should be used. An easy way to determine whether there is enough room is to cut the required number of of lengths of wire of this size and fit then into the slot.
Changes for New frequency
There are two ways to convert these motors; one keeps the same horsepower for the new speed, and the other keeps the same torque for the new speed (more horsepower). For the same horsepower, use the following formula: old turns*Sqrt(old Hz / new Hz) = new turns. If you want the same torque then it is: old turns*old Hz/new Hz = new turns.
The Following User Says Thank You to johnsattuk For This Useful Post:
Although lately I've been using this one as it's on the university computers.
Anyway, Geoffrey, have you got a picture of the stator inside your motor? I'd be interested in rewinding it / working out how for you. Who told you that it wasn't possible and what reason did they give?
I originally tried the forum in the hope that some kind soul would help with some positive info.
It is highly unlikely that I will wind another motor, this was a just a whim that became a challenge.
I apologise if I seem to be hi-jacking this thread, but I did start a somewhat similar thread about my spindle and had no response. G.
Last edited by GEOFFREY; 11-04-2014 at 01:43 PM. Reason: apologies
Impressive ! good job (Edit: The rewind I mean)
Last edited by EddyCurrent; 11-04-2014 at 02:12 PM.Spelling mistakes are not intentional, I only seem to see them some time after I've posted
Oops!! That could be my misinterpretation. Perhaps he meant not enough room to get the turns in. Anyway, they said it would be impossible - I guess they were just not interested. G.
What is the current rating of the existing motors, may be cheaper to get a VFD with enough amps to drive them, you would be able to program it for the volts.
Be interesting to see Jonathan's winding solution.
Last edited by johnsattuk; 11-04-2014 at 03:26 PM. Reason: spelling
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