Re: [CAD_CAM_EDM_DRO] Testing a 10HP Spindle with a 2HP VFD...Hmmm

I'm jealous! All I can say is I'm sure it's not recommended, but I run my
4 HP Bridgeport series II spindle motor with a 2 HP VFD, no problems
yet. It wanted a external breaking resistor to decelerate in a reasonable
amount of time. I got a killer deal on a 2 HP VFD, about 1/6th of what I
could find a 4+ VFD for, so I decided to take the gamble and decided I
won't feel bad if I blew it up right away. I also keep a LARGE household
fan blowing on the back, to keep heat down.

Some things to consider, a 10 HP motor really looks different to the VFD
(electrically) than a 2 HP motor does. Lower resistance, lower
inductance?, so even under no-load, it might make the VFD more unhappy than
a smaller motor. And obviously, the differences between a 10 HP on a 2 HP
VFD are greater than my 4 HP on a 2 HP VFD. Just plan on killing the VFD,
and you won't be disappointed! Hopefully presently surprised.

- Steven Ciciora

At 11:33 PM 9/1/2004 -0400, you wrote:

>Hi VFD gurus,
>
>What have I done! I've just won eBay item #3836015794 which I intend
>to use to replace my entire BP clone's varispeed spindle/motor etc...
>Probably not going to run it much above 12,000 RPM without balanced
>tooling but that's going to be way better than the 4500 RPM I get now
>for faster feed rates, particularly with small diameter tools!
>
>Eventually I will get a suitable 10HP vector drive VFD but as I have a
>spare 2HP VFD, I was wondering if I could at least power up the unit
>without any load just to see/hear it run? Or am I likely to break the
>VFD? Yes, I have 3 phase power at my shop.
>
>It's going to be a fun upgrade! I'll post some pics when I get it all
>up and running.
>
>It looks pretty darn cool for a spindle eh? Anyone know where I can get
>ISO30 tool holders?
>
>Cheers, Peter