matching a power supply

[krymis]

How exactly are you suppose to match up a power supply? Do you just take the max amp and voltage for one drive? I.E.: Gecko 320 is rated up to
20A/80V and industrial hobbies provides a 20A/65V power supply for 3 of them. Or is it based off of the motors?

A real world example of what i am looking at is the keling X2 3 axis setup.
The power supply provided is a 24V/8.3A. The driver (kl4030) has an input power of 24-40V/0.9-3A. The stepper motor (wired in parallel bipolar) has 4.17V/2.8A listing. How do they match a power supply to the system?

[ger21]

You match the power supply to the requirements of the motors.

For steppers, it depends on the drive somewhat, but you generally need about 2/3 of the motors rated value. So 2.8 * 3 motors * 2/3 = 5.6 amps. Add a little extra for a cushion and 8 amps is fine. Not 100% sure how to figure current reqirements for servos.

[krymis]

I am just trying to wrap my head around the gecko white pages. Also I need to figure out how to match the ps to a servo setup.

[keebler303]

It depends on what exactly you are doing. If all three motors hit peak 20A at the same time, then you would need 60A! This is fairly unlikely to occur so you can derate it depending upon how severely your machine will stress the drive components. If it is only likely to see peak current on 1 axis at a time, then the supply only needs to be a bit higher than what 1 motor peaks at. The power supply should be sized to provide the maximum current the machine will ever see.

Matt

[krymis]

ok so now i am at a few more questions...
If you are doing current then you need to take into account the # of motors. Do you need to do that for Voltage also?

Also using the keling example up top the input for the drive is only 24-40V. If you take the 4.17V times 20 (the target # from the gecko pages)= 83.4V. That is way above the drivers capability. Do you then just take the low and high voltage of the driver into account? If I did that the 24/4.17=5.76 and 40/4.17=9.52. So that puts you in the 5.76 to 9.52 times the motor voltage range to be compatable with the drive. Is that correct?

How do you know the max current your machine will reach at one time? The IH power supply, for example, give a 20A current. Does that mean that only one axis is expected to reach full current?

Sorry to do this but i would like to understand all aspects of a retrofit package.

[ger21]

Originally Posted by krymis Also using the keling example up top the input for the drive is only 24-40V. If you take the 4.17V times 20 (the target # from the gecko pages)= 83.4V. That is way above the drivers capability. Do you then just take the low and high voltage of the driver into account? If I did that the 24/4.17=5.76 and 40/4.17=9.52. So that puts you in the 5.76 to 9.52 times the motor voltage range to be compatable with the drive. Is that correct?

Yes, just use the Max for the drive. Also, if you don't need 20x the rated voltage, don't use 20x, as it will just make your motors run hotter.

[krymis]

thanks...Any help towards a servo setup or any other of the posted q's?
can a regular toroid ps be used for servos? Would it use the same equations?

[krymis]

The keling stepper motors list Phase as 2 on bipolar parallel. Then it lists rated voltage as 4.17 and current/phase as 2.8 . Do I then have to multiply 2.8 by 2 to get the correct Amp requirement for my power supply?