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### calculating setup with different z-axis motor

Posted: Mon Jul 24, 2017 8:27 pm
Hi!

i would like to upgrade my 2 y-axis motors and my x-axis motor and leaving the z-axis motor as it is.

the new motors obviously differ alot from the new motors, so my question is, how i would calculate the power supply using different motors?

the z-motor is:

Rated current: 1.7 A
Rated voltage: 6.8 V
Phase resistance: 4 ohm
Phase inductance: 14 mH
0.88 N·m, 125 oz·in

the other motors are:

Size: 56.4 mm square × 56 mm, not including the shaft (NEMA 23)
Weight: 0.7 kg (25 oz)
Shaft diameter: 1/4″ (6.35 mm) “D”
Steps per revolution: 200
Current rating: 2.8 A per coil
Voltage rating: 2.5 V
Resistance: 0.9 Ohm per coil
Holding torque: 13 kg-cm (180 oz-in)
Inductance: 2.5 mH per coil

using a geckodrive g540 as driver and a 36V 10A power supply, but i think i would have to upgrade to 48 for the strongers motors, right?

would i have to transform the power down leading to the z-motor or could i leave them as they are?

thanks!

### Re: calculating setup with different z-axis motor

Posted: Tue Aug 01, 2017 12:48 am
You don't need 48V for those motors, but they'll be stronger if you do. It's the amperage you need to think about. Your current PSU is probably fine, but 10 amps may be pushing it. Assuming those ratings are correct, you're looking at 10.1 amps. I'd probably substitute for a 12 or 15 amp PSU (and if you're doing that, you may as well go 48V, but it'll be more expensive than a 36V).

Are you already using the G540, or upgrading to it? That board requires current set resistors for each motor, so you'd just put the appropriate value for each of X, Y1, Y2, and Z. The G540 will limit the amps according to that.