Yes, those are the servos. I bought them from Jeff Davis (HomeCNC) a while back. He modified them to accept the US Digital encoders and a NEMA 23 style mounting plate. He also tested them with a Gecko 320 drive with good results.
Here are the specs:
Use a 36VDC power supply.
No-load RPM at 36VDC = 3,130
(Ke = 11.5, KRPM = 36V / Ke)
80% of no-load RPM = 2,500 RPM
Leadscrew RPM @ 120 IPM, 5TPI = 600RPM
Reduction Ratio = 2,500 RPM / 600 RPM = 4.1666:1, Use 4:1
Kt = 1.351 Ke = 15.5 in-oz / amp
Maximum continuous current = 3 Amps
Maximum continuous torque = 3A * Kt = 46.5 in-oz
Torque on leadscrew = 46.5 in-oz * 4:1 reduction = 186 in-oz
Leadscrew thrust = pi/8 * TPI * in-oz = 365 lbs
Maximum speed at full load = 2500RPM /(ratio * TPI) = 125 IPM
Maximum speed, no-load = 3,130RPM / (ratio * TPI) = 156 IPM
Power delivered to load = RPM * in-oz / 1351 = 86 Watts
A link to the servos:
http://www.automec-direct.netfirms.c..._dc_motor.html
Here is a quote from Jeff in the other thread:
Yes, I finished my testing and I have the full specs on these motors.
They are the next size smaller than the ones I get new from Poly-sci. They are 360 oz/in peak motors at a peak of 20 amps. This means they have an 18 oz/in per amp rating.
Testing results:
Made a bar that had a hole 1" from the center and placed a wire hook there to attach to a bucket. The only thing I had to add for weight was 45 cal bullets. I had my Gecko drives current limited to around 10 amps. I kept adding weight to the bucket and lifting the bucket with the servo motor. I got to a point where the motor would just lift the weight past horizontal and then the drive would fault and the bar would fall down vertical. I weighed the bucket and it was close to 11 pounds. So it lifted 11 in/lbs with my current limited to around 10 amps.
This is very close to what my Poly-Sci specs say. If you do the math, the spec says 18 oz/in per amp. So 18 * 10 amp is 180 0z/in. Convert that to pounds would be 180 / 16 = 11.25 lbs. I'm a 1/4 pound off. Maybe I don't have the current limit screw set to exactly 10 amps
The perfect power supply for these would be a 36VDC supply @ 20 amps. You could leave the Gecko drives current limit screw all the way up to 20 amps. This way if you needed the current for one axis that is working hard it can take what ever is available from the power supply. |