1. ## advice on voltage and amps to run higher RPM

im using 3 425oz steppers with a 36v 10 amp power supply. my drivers are rated for 18-56 volts and up to 4 amps. currently im giving them 36vs and 2.15 amps per stepper motor.

im not sure if these 425oz are able to go any faster. the fastest axis i have is the y axis using 8tpi. i can run it up to an inch per second. so thats 8 rps. sould this stepper motor be able to go faster than that? would upgrading the voltage or amperage make it run faster?

2. Generally speaking it's the amps that give you the torque and the volts gives you the speed. If all three drivers pulled 4 amps then you'd need 12, but it's normally understood that this doesn't happen, so your 10 amp supply seems OK. But you could use more volts - up to 56 - and you'd then get more speed.

I normally think of feed rate on a per-minute basis, so you're getting 60 inches per minute. It depends how big your machine is - mine is tiny, so I'm happy with a lot less than that.

3. Generally you want to run at the steppers rated current and at a voltage equal to (32*(L^1/2)) where L is the steppers inductance in milliHenries. If this value is higher than the drive's max voltage then run at the drives max voltage. Be sure to read 'Step motor basics' on the support page for Geckodrive even if you're not using Gecko products. It's very instructive.

To get more speed you might want to consider a higher lead screw. You're typically getting into the region of rapidly declining torque at 8 rps. Screws with 4TPI or 2TPI would give an improvement in speed though at the expense of resolution.

Chris

4. Doubling the voltage will double the speed. Increasing the current setting will probably increase your speed. Note, that you do not need to restrict the total current to 10 amps. Try setting the currents to 4 amps per motor and see if it's good enough. If not, get a higher voltage supply.