Re: [CAD_CAM_EDM_DRO] Low range gears on Bridgeport Series 1

In a message dated 04/28/2001 2:05:02 PM Hawaiian Standard Time,
mcamp@... writes:

> I would be very concerned about the quadrupled available hp, how are you
> going to prevent your self from using it? There seems like
> there is great potential for machine damage here. I suggest that you limit
> the current in your VFD so as not to exceed the original
> current to the motor. Let us know how the tests come out.
> Bob KB1FRW
>
>

Bob, Sven and John,

Yes, most likely I will reduce output current to prevent from getting
carried away. I can't recall ever stalling the 3/4 hp except for feeding a
part in the table feed high range by mistake etc. I've been machining on Bp's
for many years, I don't think I will suddenly double or triple "safe" cutting
rates. I used the 3 HP cause it was low cost and I had a VFD that matched it.
The next size down I have is a 1 Hp and that I know has virtually no low
speed torque.

I think I will keep the back gear, gotta get bearings and dive in. I did not
consider how changing carrier frequencies would smooth the motor out. I can
run it at 6 Hz and tap 1/4-20 in stainless with no sweat. I tried running it
at 5 Hz for an extended time to see if it heated up. Though it was with no
load, it did not even get warm. The last 1 HP I played with got too hot to
handle after a short while....

Will update you folks again as we learn more.

Peter
THRD, Inc.


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