different size motors

[woodlice]

Can you use different size motors on a cnc router or will this cause problems like needing 2 power supples for the different volt amp ratings say nema 34 600 oz/in and nema 24 200oz/in?

[cueshark]

you did not say if they are servos or steppers. if they are servos they need to be real close in volts. if they are steppers then you would need a power supply that would be between 10 & 20 times the volts on the different motors. so you could be 10 x the volts on 1 motor & if the other motor specd half the volts as the first motor it could be 20x & you would be ok with the right ps. hope this helps more info on the motors would help.
greg

[woodlice]

I was thinking of using 2 x nema 34 KL34H280-45-8A 640 oz/in 6.3A 2.3v 8 wires for x,y and 2 x nema 24 KL23H2100-30-4B 495 oz/in 3A 3.6v 4wires on the MDF CNC Router im building. It has grown from 600x600 to1mx1m. I'm really warried about using to small a motor but do you think this is over kill? would I have to have 2 power supplies or 2 driver boards or should I just go with 4 of the same motor? The motors are from Keling Technology, Inc. www.kelinginc.net

[bobchiloquin]

cueshark,

I'm a little confused. You talk about running steppers at 10-20 times the rated voltage. Does this mean I could run a 24v, .3A, 6 wire stepper at 240v to 480v without fear of it burning up?

Bob Hayes

[ger21]

Originally Posted by bobchiloquin cueshark, I'm a little confused. You talk about running steppers at 10-20 times the rated voltage. Does this mean I could run a 24v, .3A, 6 wire stepper at 240v to 480v without fear of it burning up? Bob Hayes

Possibly, if you could find a drive that would handle that kind of voltage. Most steppers used in CNC applications are in the 1.5V-5V range. And most users use power supplies in the 36V-72V range. Gecko drives are limited to 80V, and cheaper drives are usually less.

[bobchiloquin]

Gerry,

So my 24v steppers(Eastern Air Devices, p/n LA23ACK-3) probably aren't strong enough for my modified Joe's Hybrid router. There's no indication of torque on the nameplate. Y axis slides are modified, ball bearing, undermount drawer slides, mounted on 80/20 2x4 extrusions.

Bob Hayes

[jeffs555]

Does this mean I could run a 24v, .3A, 6 wire stepper at 240v to 480v without fear of it burning up?

Bob,
When running a higher voltage than the motor rating, you do need some way to limit the current. Most modern drives have some way to set the current. However, there are still a few drives being sold with no current setting, and if you get one, you will need external current limiting resistors in order to run higher voltages(current limiting resistor generate a lot of heat).

The reason for higher voltage(ie 10-20x the rated voltage) is maintain good torque at higher speeds. Higher voltage will make little if any difference in low speed torque. The torque from a stepper drops off as speed increases. Using higher supply voltages lessens the drop in torque. The reason you want motors rated 5 volts or less is that most drives have a voltage limit of 30-50 volts and even the better drives rarely handle more than 80 volts.

Jeff