Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Posted by
Kim Lux
on 2004-01-06 08:31:54 UTC
On Mon, 2004-01-05 at 22:14, Gregory Kamysz wrote:
high on these motors.
2000 RPM would be 400 ipm. The largest travel we have these motors on
is a lathe with 40 inches of bed travel, so the time they would be at
this speed would be small.
Kim Lux <lux@...>
> I don't think that 40V and 4 Ohms is realistic for this motor unless4 ohms might be over stating it, but the armature resistance is fairly
> it's huge. That would be 400W in heat.
high on these motors.
> Also if 10A was the maxI'll stay out of this.
> possible current than this would be stall torque and not rated torque.
> Torque would decrease as soon as the motor started turning with a 40V
> max input.
> Operating the motors at voltages over the specified voltage is OK asThe only time the motor is used at those speeds is on rapid traverses.
> long as it holds together mechanically. However you will have to derate
> the 10A continuous if you intend to run the 2500RPM for a long period of
> time with significant load.
2000 RPM would be 400 ipm. The largest travel we have these motors on
is a lathe with 40 inches of bed travel, so the time they would be at
this speed would be small.
> It will not handle 2500RPM and 10A if theAgreed.
> 1800RPM limit was related to heat rather than mechanical issues. If you
> look inside the motor and the windings are tied and wedged then
> mechanically it should be sound. It's hard to say exactly why the
> manufacturer marks a specific RPM value.
> If you are doing it simply toOK.
> speed up your rapids(where the current will be pretty low) heat
> shouldn't be an issue. Brush bounce can be an issue, this is one cause
> of arcing.
> I fly electric model airplanes and running motors above the ratedCooling is the key.
> voltage isn't an issue except for brush and comm wear. In that
> application cheap motors are expected to be scrap in a few hours of
> operation so it doesn't matter. When using high quality motors they can
> handle the abuse and brushless motors don't mind much at all as long as
> you keep them cool enough.
> In models the thermal mass absorbs most ofAgreed.
> the heat, convection and radiation doesn't come into play unless you
> have very large batteries. However in the shop if you want to push a
> motor adding a fan will let you get a bit more out of the motor. You
> then have to worry about the reliability of the fans.
>
> Yes, by the book you may want to change the ratio to get more speed, but
> at what cost? In this case adding a gearbox would add complexity, cost,
> increase drivetrain losses,...etc.
> The above applies to DC permanent magnet motors.--
>
> Greg
>
>
> Kim Lux wrote:
>
> > I'd like to "over voltage" the motors so that they can run at a higher
> > speed. These motors have significant armature resistance and with a 40V
> > power supply we run out of supply voltage long before we are anywhere
> > near the peak current of the motors.
> >
> > The max voltage spec on these motors and servo motors in general is
> > pretty soft. More important that max voltage is not exceeding a
> > practical speed limit, not exceeding max current, etc.
> >
> > Kim
> >
> >
> > On Tue, 2003-12-23 at 17:31, industrialhobbies wrote:
> >
> >>Color me ignorant. But why would you over-volt your servos so much?
> >>I run and sell Pittman's which are 24v motors, I can do 180 IPM
> >>rapids and all that other stuff. So what will you gain? Up to a few
> >>volts over isn't all the extra power just going to heat? Which
> >>servos don't like.
> >>
> >>Not that I'm attacking your position. If it works for you I wish you
> >>all the best.
> >>
> >>I'm just curious as of why?
> >>
> >>Thanks
> >>Aaron Moss
> >>www.IndustrialHobbies.com
> >>
> >>
> >>
> >>
> >>--- In CAD_CAM_EDM_DRO@yahoogroups.com, Kim Lux <lux@d...> wrote:
> >>
> >>>We are running the them with 40 volt supplies, Gecko 320s and US
> >>
> >>Digital
> >>
> >>>encoders, 500 CPR. With a 5 TPI ballscrew, this combo gives
> >>
> >>1/10,000"
> >>
> >>>resolution and 150 IPM using TCNC.
> >>>
> >>>If I had to do it over, I'd use 60 or 80V supplies. It sounds like
> >>
> >>the
> >>
> >>>new version of TCNC is going to have a much higher stepping rate and
> >>>will allow 250 IPM with this sort of set up.
> >>>
> >>>Kim
> >>>
> >
>
>
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Kim Lux <lux@...>
Discussion Thread
ja_erickson
2003-12-22 15:59:38 UTC
Question for Kim Lux
Kim Lux
2003-12-23 08:14:14 UTC
Re: [CAD_CAM_EDM_DRO] Question for Kim Lux
industrialhobbies
2003-12-23 18:36:54 UTC
Re: Question for Kim Lux
Kim Lux
2004-01-05 08:46:37 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Robin Szemeti
2004-01-05 11:19:50 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Kim Lux
2004-01-05 12:59:28 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Bob McKnight
2004-01-05 15:21:20 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Kim Lux
2004-01-05 16:11:14 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Robin Szemeti
2004-01-05 17:27:42 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Gregory Kamysz
2004-01-05 21:12:41 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux
Kim Lux
2004-01-06 08:31:54 UTC
Re: [CAD_CAM_EDM_DRO] Re: Question for Kim Lux