Re: [CAD_CAM_EDM_DRO] Beaver Mills & Motors

info.host@... wrote:

> >First off the motor will be 4 pole 1425 rpm. It gets the top speed
> >from gearing up.
>
> Lower speed on the same power, more torque. What else does 4 pole offer? If
> nothing then they could just use 2 pole and only gear down. Is it a little
> smoother?

A 2-pole motor runs at twice the RPM as a 4-pole. For the same HP
rating a 4-pole will have twice the torque of a 2-pole.

> There is a small handle on the side of the head, is this for tensioning the
> belts for when it's time to change speed and therefore belt position?

Could be. bridgeports have handles bristling all over them. there is a
spindle brake on top, a direct drive clutch handle up there, too. Then,
there's a handle that loosens the motor for belt groove changes, a
back gear lever, a feed worm lever, power feed rate selector, power
feed direction selector, the power feed engagement knob, and probably
a few more. 2J heads with the variable speed move the direct clutch
and back gear engage to one handle, and add a speed control dial.

>
> Got it, we did this ages back in physics. I didn't recall the HP on the
> motors was their electrical input power, not shaft mechanical power. Wait a
> second, we did that in physics too. Thanks for the reminder.

No, motors are rated at their mechanical output. But, the power input
can be pretty accurately estimated from that. The current draw and
power factor, however, are much more variable by motor design.

Jon