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Author Topic: Interchangeability of Grafar UK 3- and 5-pole motors  (Read 285 times)

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Offline Dr Al

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Re: Interchangeability of Grafar UK 3- and 5-pole motors
« Reply #15 on: March 15, 2019, 12:32:25 AM »
As an aside, and for reference and interest - all of Farish's new tool models have 3 pole can or coreless motors.

Cheers,
Alan
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If Dr Al is online he may be able to provide a more comprehensive answer.

“We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.” – Dr. Carl Sagan

Online V72

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Re: Interchangeability of Grafar UK 3- and 5-pole motors
« Reply #16 on: March 19, 2019, 12:11:15 AM »
I will measure performance of the 3-pole and compare with performance after change to 5-pole, knowing that I can always go back to the 3-pole. I'll  use the same grey white-spot magnet and the same brushes for these tests. Probably, next week will be the first opportunity.
I haven't opened up a canned coreless motor but assumed them to 5-pole. It's really an eye-opener, Alan, to learn that they are actually 3-pole, since their low voltage performance is really smooth.

Cheers, Steve

Offline Dr Al

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Re: Interchangeability of Grafar UK 3- and 5-pole motors
« Reply #17 on: March 19, 2019, 12:19:26 AM »
I haven't opened up a canned coreless motor but assumed them to 5-pole. It's really an eye-opener, Alan, to learn that they are actually 3-pole, since their low voltage performance is really smooth.

Precisely the result of being coreless, so no cogging between poles.

I tore a dead one down a while back, which is why I know:


The size of the coreless motor is such that it would simply be impracticable to wind five coils in it, and even more to produce a robust commutator at that size - it's notable how small motors are all 3 pole - the Farish armatures and the Mashima 1015 are some of the smallest 5 pole out there.

Cheers,
Alan
Quote from: Roy L S
If Dr Al is online he may be able to provide a more comprehensive answer.

“We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.” – Dr. Carl Sagan

 

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