Help Selecting a Power Supply

[millman52]

I have read piles of information on power supplies & I'm still somewhat lost. I'm not looking to build a PS at this point. Just need help in selecting what will fill my needs. & what vendor to purchase from.

I will be using (4) Gecko 203V drives Powering (3) 740 Oz in 4 wire parallel NEMA 34 hybird steppers & (1) 500 Oz in 4 wire parallel hybird stepper.

This system is going to run a burning table so there will be very little friction load to overcome. but adequate speeds will be needed to operate plasma.

If the above listed information is to general. Please ask for the specific information needed.

[Nono]

Maybe this will help..

[millman52]

Ok, thanks based on those design parameters I am going to need around 48V, 15.5A. Now for the next part of the above question. Who carries one available, ready to ship?

[neilw20]

Originally Posted by Nono Maybe this will help..

Yes a single point earth is a good idea, but it should be on the capacitor NEGATIVE TERMINAL.

Much heavier wires than in pictures.

Scheme is AC to the rectifier direct from transformer or via some terminal strip. That's OK.

The PLUS and MINUS from the bridge should go DIRECT to the capacitor(s) so that the only current going through the supply wires is RIPPLE CURRENT.
Then take a pair of wires form the CAPACITOR +/- for EACH stepper motor controller either through connector blocks or DIRECT to the controller.
Each controller should have its OWN set of supply wires, and your common point negative if you still need one should be run DIRECT from the negative of the capacitor.
Read the instructions in the Gecko Manual. From memory this is very close to what Gecko suggest. Also if supply wires to each controller are further than 12" from the capacitor another capacitor is needed at the controller so that the ripple currents don't create havoc.
If you just use point to point wiring, the micro stepping controllers may start to do erratic and unpredictable things, which are almost imposible to diagnose and defeat.
Daisy chained point to point wiring, like hooking up light globes is doomed to create weird faults.

Don't forget to measure and set the current limits on the controllers.

[tauntdesigns]

I got a 65vdc/15a power supply from Keling and they have other configurations.
http://www.kelinginc.net/SwitchingPowerSupply.html

IIRC:
Amps
Add up the amps of all your motors and multiply that sum by .66 equals the amount of amps your power supply should have (or more).

Example:
3 motors at 4amps
3 times 4a equals 12 times .66 equals 7.92
So I'd get a power supply with 8 or more amps

Volts
On Gecko drives I used the 4 to 20 rule. I picked a power supply that fell inside 4 20 rule.

Example:
Let's say you used motors rated at 3v

4 times 3v = 12v
20 times 3v = 60v

So I'd pick a power supply between 12v and 60v (higher the better)

I hope I helped,
Jack

[millman52]

From looking at their list I assume you are referring to the KL-6515 that also has taps for 5 & 12 V.

Originally Posted by tauntdesigns I got a 65vdc/15a power supply from Keling and they have other configurations. http://www.kelinginc.net/SwitchingPowerSupply.html IIRC: Amps Add up the amps of all your motors and multiply that sum by .66 equals the amount of amps your power supply should have (or more). Example: 3 motors at 4amps 3 times 4a equals 12 times .66 equals 7.92 So I'd get a power supply with 8 or more amps Volts On Gecko drives I used the 4 to 20 rule. I picked a power supply that fell inside 4 20 rule. Example: Let's say you used motors rated at 3v 4 times 3v = 12v 20 times 3v = 60v So I'd pick a power supply between 12v and 60v (higher the better) I hope I helped, Jack

[tauntdesigns]

Yea, that's the one I got.

I got 2 425 oz/in wired parallel (4.17v, 2.8a) series (8.4v, 1.4a)
I have 1 640 oz/in wired series (4.5v, 3.2a) parallel (2.3v, 6.3a)

I bought everything before I understood exactly what I needed. I looked at the motors specs for parallel on both and added up the amps (2.8 + 2.8 + 6.3 = 11.9) and was thinking about adding a 4th axis later, so I looked for a 15 amp power supply.

While I was waiting for everything to get here I kept reading and reading. I started understanding better what other here in the zone were saying.

While looking at the 4 20 rule.... all the motors wired parallel I realizes I had a problem.

425oz/in motors parallel (4 x 4.17v = 16.68v and 20 x 4.17v = 83.4v)
My 65v power supply fell inside those numbers

640oz/in motor parallel (4 x 2.3v = 9.2v and 20 x 2.3v = 46v)
oops, my power supply is to big for it.
So I looked at wiring it series (4 x 4.5v = 18v and 20 x 4.5v = 90v)
My power supply fell inside those numbers.

Since I changed the wiring of the 640 motor the amp rating for series wired motor 3.2a instead of 6.3a. So 15 amps is a little overkill for my needs but, You set the amps on the gecko with a current set resistor.

Everything worked out in the end

Later

[neilw20]

Your motors might be able to faster than you expected!