Adding a second transformer for a servo

[bgolash]

Hi
I have a stepper cnc and had a problem with lost steps. Its
my belief that the 286 oz*in stepper was just too small for the
machine. The z axis hanging weight approaches 85 pounds.
As a experiment I`m going to update the z and use 360 oz*in
servo from Jeff at homecnc.com. I`m going to use a 2 to 1
ratio to increase the torque to 700 oz*in.
I have one transformer that feeds two steppers. I need to
build a second transformer for the servo. I plan to use a 24 volt
10 amp transformer. I`m wondering if this is large enough to
run the single servo. The servo is rated for 12-60 VDC at a maximum of 20 amps.
The capacitor for the power supply is 75 volts and 10,000 uf. Will
that be enough for the motor. Will be using a Gecko 320
Thanks

[unterhaus]

torque is related to current, so cutting corners on current will possibly hurt you there. However, I doubt that 20 amps is probably a max current, so you could be ok. Voltage is related to speed. Whatever the max speed will be degraded by a factor of 24/60.

[H500]

bg: You're probably wasting 60% of the motor's capabilities by driving it with only 24v. The proper approach is to drive the motor to the full RPM and then gear it down to the max RPM you need. You'll be amazed at how much more power is unleashed.

[ViperTX]

Well it would be better to have a large capacitor.....but it will work....

[ejkoeze]

As a rule of thumb we here in Europe say you need at least 1000uF per Amp for the cap. Running a 60V motor @ 24V is really a waste. Better buy suitable 24V servo's or upgrade your PS. Problem is to get 60V dc under load your non load DC voltage will be dangerously close to the voltage limit on your cap.
DC voltage unloaded is ~1,4 times AC rated voltage of transformer
DC voltage loaded is ~1,2 times AC rated voltage of transformer
This means you'll need a 50V secundairy transformer that'll give you 60V DC under load. 50x1,4 = 70V is near 75V of cap.
Overloading cap is nice fireworks display

Erik Jan