Re: Motor calculations? Help!

This is actually a Pratt & Whitney Tape Mate C. It is not that big.
It weighs about 4500 lbs. These are the motors it comes with.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
> snaketracks wrote:
>
> >
> >What calculations could I use to figure out the max voltage and
> >current specs on these motors? I am trying to figure out what
> >voltage to make the power supply and which drivers to get. I want
to
> >have enough supply to run the motors up to the max rating of 2000
> >RPM, so I think the power supply has to be somewhere above 50V
for
> >the Z axis motor and above 100 Volts for the X and Y going by the
> >back EMF that has to be overcome. I just don't know how much
higher
> >or how to calculate it. Or I could even be way off base. Any help
is
> >much appreciated. Please e-mail me at jevs@c... if you have
> >any ideas. Here are the only motor specs, I had to pester Fanuc
with
> >about 10 phone calls before they would even give me this. They
are a
> >pain to get info from:
> >
> >Fanuc DC Motor 0 (z axis)
> >Type: 0-2000M
> >Output Power: 0.4 KW (0.5 HP)
> >Rated Torque: 28 Kg-Cm
> >Max. Torque: 240 Kg-Cm
> >Max. Speed: 2000 Rpm
> >Rotor Inertia: 0.029 Kg-Cm-S 3
> >Back EMF Constant: 25 V/K RPM
> >Torque Constant: 2.44 Kg-Cm/Amp
> >Mechanical Time Constant: 25 mSec
> >Thermal Time Constant: 50 Min
> >Weight: 12 Kg
> >
> >
> 2000 RPM needs 50 V plus an allowance for I*R drop. I don't see a
> figure for armature resistance,
> so I can't calculate farther on that. at 2.44 Kg-Cm/Amp, and 240
Kg-Cm
> peak, the peak current is
> 98 Amps!
>
> >Fanuc DC Motor 5 (x,y axis)
> >Type: 0-2000M
> >Output Power: 0.8 KW (1 HP)
> >Rated Torque: 55 Kg-Cm
> >Max. Torque: 480 Kg-Cm
> >Max. Speed: 2000 Rpm
> >Rotor Inertia: 0.05 Kg-Cm-S 3
> >Back EMF Constant: 50 V/K RPM
> >Torque Constant: 4.87 Kg-Cm/Amp
> >
> >
> 50 V/KRPM * 2 (000) = 100 V + I*R. I peak is 98.5 A. I'd think a
150 V
> supply would be
> good here. Hmm, I assume you will be retrofitting a Kearney &
Trecker
> horizontal boring
> mill or similar monster machine with motors like this! These X-Y
motors
> could crank a
> large V-8 engine with no direct drive to the crankshaft! Do you
really
> need to hang a 16 Kg
> motor on your axes? Can your leadscrews and structure withstand
such a
> motor?
>
> Jon