Re: [CAD_CAM_EDM_DRO] Questions - 90V/120V motor ok?

alex wrote:

>
> Doug,
> thank you for an explanation!
> Let me ask you: Can I use only half of the rated voltage of this motor,
> say 36V? Will I loose lots of torque in this case? I'm concerned
> that 90 V 20 A power supply will be too expensive plus I don't
> need that much of an RPM anyway.

To put numbers to it, I have one of those treadmill motors here,
90VDC 6000rpm (model LP101230 by GS Electric B4CPM-060). Using a
75VDC supply, you'd expect to get 6000*75/90 = 5000 rpm.

As I understand, the torque is undiminished, but the rpm at 36V
would be 6000*36/90 = 2400 rpm.

What the torque actually is, is unknown to me, but the motor is
the same dia but half the length of the (considerably more expensive
and expensively made) 1/4 HP 90VDC Leeson motor, which has a 72 oz*in
continuous rated torque.

So in summary, 2400 rpm might be enough, but is the torque enough?
You might have to run it at 5K rpm and use a 2:1 reduction gear
ratio to double the torque. Even then, it may not be enough for
your application. With sufficient gearing down, the torque may
be right, but the resulting movement slower than we'd like.

But for learning and hobbiests not in a hurry, it is a good tradeoff.

regards
Doug Fortune
http://www.cncKITS.com


















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