Re: Is it possible to change the BP motor to eliminate shifting?

Thanks everyone, At second blush it looks like the shifting is going
to have to stay. I like the idea of a stepper motor in place of the
spindle, but the way these motors loose torque at high rpm might
creat the opposite problem. At least NC control of the spindle
speed in the two ranges will be a great improvement.

Thanks,
Keith


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Peter Reilley"
<micrio@m...> wrote:

> Perhaps the best way to think about it is with an analogy. Could
> you have a car without a transmission? The answer is yes.

However,

> you would have to make some choices. If you pick a fixed ratio
> that allows you to go highway speed then you will accelerate very
> slowly to get to your desired speed. There are some hills that

you

> could not climb.
>
> If you choose a ratio that allows you to go up any hill then you

would

> not be able to reach highway speed. Driving around town would be
> fine.
>
> Of course you could install a very large engine that would have

enough

> torque for any hill but would still reach highway speed. The

downside

> is gas mileage and cost.
>
> The transmission in your car like the transmission in your

Bridgeport

> gives you the ability to use a motor of reasonable size to do most
> any job that you want.
>
> In the early days of automatic transmissions for cars they used a
> torque converter but few gears. Some cars had two speed

transmissions

> or even one speed. They depended on the torque converter to
> multiply the engines torque. Torque converters, then and now,

cannot

> produce the torque range that a gear box can. These cars

accelerated

> at a majestic (slow) rate as my father remembered. He recalls

driving

> some way back then. This probably slowed the acceptance of

automatic

> transmissions. Most people bought standard transmissions.
>
> Pete.
>
>
> ----- Original Message -----
> From: "Keith Clark" <mail@t...>
> To: <CAD_CAM_EDM_DRO@yahoogroups.com>
> Sent: Sunday, April 10, 2005 11:14 AM
> Subject: [CAD_CAM_EDM_DRO] Re: Is it possible to change the BP

motor to

> eliminate shifting?
>
>
> >
> > I was wondering if there some more powerful motor or other way to
> > gear it to maintain the torque in the low range?
> >
> > Thanks
> > Keith
> >
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Lance Hopper"
> > <snaggletto@c...> wrote:
> >>
> >> Yes, you can use a VFD, to control the speed of the motor.
> > However,
> >> you will lose tons of torque (cutting power) at lower RPM's by

not

> >> using the backgear (low gear range). This would render the
> > Bridgeport
> >> nearly useless while using larger diameter cutters at low RPM.
> >>
> >>
> >>
> >>
> >> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Keith Clark"

<mail@t...>

> > wrote:
> >> >
> >> > Is it possible to change the 2 HP motor on my (Series 1
> > originally
> >> > Boss controlled) Bridgeport spindle during conversion to

control

> >> > spindle speed, to a motor that could have the entire speed

range

> >> > needed and thus obviate the need for the gear shift?
> >> >
> >> > Thanks,
> >> > Keith
> >
> >
> >
> >
> >
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