Re: [CAD_CAM_EDM_DRO] Servo survey.

r_fl_z@... wrote:

> In an effort to ensure the correct choice of servos for my 3-axis
> machine, I'd like to hear what motor sizes are being used for the
> axis drives by list members who are using servos.

Machine is a round-ram Bridgeport (older model, just a little smaller
than standard Series-I Bridgeport machine).

I installed precison ballscrews with 5 TPI for the X and Y, and 10 TPI
on the Z.

I have 1/8 Hp (cont. duty rating) GE shunt-wound brush servo motors
on the X and Y. That's a 1/8 Hp rating at 1725 RPM, a very good
rating point for this use. The motors have that continuous rating point
at 75 V, 1.54 A. I allow them to go to about 5 A at about 60 V or
so, as set by the servo amps. So, that works out to a peak rating
of 1/2 Hp. The motors drive the leadscrews with a 2.5:1 belt reduction
ratio, using toothed belts. I don't try to go over 120 IPM, as my
DC power supply doesn't put out quite enough voltage to go much
faster.

I am using a Yaskawa minertia motor from a high-performance tape
drive for the Z axis drive. It is rated at 28 V, 14 Amps, but I don't
drive it anywhere near that current level. I use a 4:1 belt reduction
ratio on this one.

Jon