Re: [CAD_CAM_EDM_DRO] Re: Gecko and Servos Again !

Bill,

Believe me when I say that I have no idea about stepper equivalency
but I have three of these motors with G340's waiting to be connected
to them. After talking to Mariss when I was ordering the 340's he
suggested that I could calculate maximum peak torque by chucking the
shafts of the motor in a drill press and measuring the voltage and
current output when the motor was spun. Here are the notes I took
while on the phone:

To calculate the continuous torque of a motor:

Hold the motor in a vice, chuck up the motors output shaft
in a drillpress set on slow speed. Turn on the drillpress
and measure the voltage on the power connectors (VDC).
Switch the voltmeter to DC amps and measure the amperage.
Putting the voltmeter into DC amps puts a load on the motor.
This load will try to spin the motor in the vice. Caluclate
armature resistance by dividing the motor output voltage by
current. To calculate mechanical peak torque divide rated
voltage of the motor (30 volts for instance) squared by
four times the armature resistance ie.

V*V
-------
4R

Use half this value and the continuous torque.

If I got this wrong hopefully Mariss will find it in his heart to
correct me :-) Here's the results I got for one of the motors:


5.68 VDC
3.33 DCA

1.7057 Armature Resistance

131.91 Max. Peak Torque

Hope this helps,
Drew


wanliker@... wrote:

>
> How about the following:
>
> What size stepper would this be equivalent to?
>
> 2600 RPM GLOBE MOTORS, #537A274. 30.3 VDC permanent magnet reversible motor.
> The motor has ball bearings and has an optical encoder mounted on the rear.
> The no-load speed is 3780 rpm, no-load current is 0.2 amp. With a load of 60
> oz-in, the rpm is 2600 @ 5.6 amps. This is a very powerful cool running
> motor. The encoder employs a Hewlett Packard HEDS 9100 read head with a
> custom encoder disc. The encoder has a two-channel quadrature output with 512
> counts per revolution. The encoder requires 5 VDC at approx. 40 mA for
> operation. The shaft is 1/4" dia. x 7/8" long. The shaft has a flat running
> full length. The motor has four tapped mounting holes on the shaft end of the
> motor face. The holes are tapped for #6X32 tpi screws. The bolt centers are
> 1-1/16" apart. Electrical connections are made via 3/16" quick connect tabs
> connected to the brush bosses. Dimensions: 2-1/8" dia. x 5" long. Stock
> #DCME9950
>
> Thanks,
> bill

--
Drew Rogge
drew@...