Re: [CAD_CAM_EDM_DRO] Thanks - was: Things to check? is now: RUNNING~!

On Thursday 18 September 2003 11:09 am, Tim Goldstein spake:

> > No, no... we're down to 75VDC now, thanks to Mr. Variac.
> > (...and what a kewl little thing he is, too...)
>
> In the context of limits and motor heating 75 VDC is way up there. What
> is the voltage rating of the motors? If is about 3 you are way up on the
> curve where the majority of your heating will be due to iron losses
> (result of high over voltage). Look at the Gecko whitepaper curves and
> you will see that at the upper end of the recommended 10 - 25X
> overvoltage range the iron losses go up very steep.

<huge deafening bell goes off in Weyland's head at this point>

Oh-oh...
Wait a minute.
See if I'm doing this correctly, please.
Looking up Ohm's Law, if I multiply the current
by the resistance, I should get the normal voltage.
Izzat right?

Then, if I'm using 3.5A, and the phase
resistance is 1.29Ohms, I should be using 4.5 VDC.
Correct?

So, while 75VDC might be at the higher
end of the scale, it should still be okay, no?
Knowing this, what would be safe?

65VDC?

More in another post...

Weyland