Re: Power Supply for Gecko 320 and servo motors for 3 axis router

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "plastiguy" <plastiguy@a...>
wrote:

> Hi folks -
> I'm putting together the power supply for a 3 axis router using 3
> Gecko 320 drives with 3 DC Brush servo motors at 360 oz-in peak
> torque. The motors are rated at 36 vdc. I want to make sure I'm
> sizing everything correctly. My guesstimation is total maintained
> current draw for all 3 motors will be around 12 amps (20-25 peak

amps

Scott: Most of your questions have been answered by others. One
thing you might not have realized is that a 36V AC transformer will
end up giving you over 50VDC out. That means you are over the rating
of a 50V cap and your 36VDC motors. On Servos you need to adhere to
the nameplate voltage specs. On steppers the nameplate current is
the limit. If you shop for a 24 V high current transfomer (Check
www.MPJA.COM or American Science and Surplus or other surplus outlets
to find want you want) you will end up with about 33VDC nominal from
the filter cap. While motors and transformers and other magnetic
components are pretty forgiving of temporary overloads you don't want
to design something that would allow your motors to burn themselves
up under a heavy load.

Servo motor torque ratings are much more realistic since they are
taken at higher working RPM instead of at stall like steppers. A 360
oz/in servo will have that torque across a wider range of its RPM
than a similar rated stepper. Combine that with the gearing you can
add to step down the higher RPM's and the torque really climbs. I
run a pretty big machine with 120 oz inch servo motors. I have 3:1
belt gearing and about 7:1 screw advantage so two little wimpy motors
drive a 120 lb gantry at 180 IPM. I could go faster but my ballscrews
would jerk themselves out of their mounts!