Author Topic: stepper motor  (Read 71 times)

timpep

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stepper motor
« on: February 12, 2018, 03:32:42 PM »
Hi
newbie here
I wanted to know how to tell what voltage stepper motors i should by to use with the 2 axis mana se and the 3 axis mana se boards?
I see different voltages available   looking at nema 17
Thank You
Tim

rpt007

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Re: stepper motor
« Reply #1 on: February 13, 2018, 02:33:09 PM »
Hi,

A quote from the source below:

Quote
Perhaps one of the biggest points of confusion is the discrepancy between the coil voltage listed on a stepper motor’s datasheet and the usually much larger power supply used with it. If the datasheet lists a coil voltage of 3.4 volts, how is it that it can be used with a 48VDC power supply? Or an 80 volt power supply for that matter?   

This is the deal. Ignore the voltage rating. Pay close attention to the current rating instead.

This can be done because most stepper motor drivers available are called chopper drives. These drives monitor the rise of the coil current and ignore the coil voltage. When the current gets to a predefined threshold (the maximum motor current), it shuts the power to the motor off. Or chops it. Don’t exceed the maximum voltage rating of your driver. That value is not a suggestion.

Motors are driven by current, and the driver (on a Mana it's an Allegro A4988) has to provide enough (but not exceeding the maximum rated value!) current to make the motor turn.
Normally the machines come with EleksMaker® 42HS34-1304A stepper motors which perform pretty well if you only use them for laser operations.
The datasheet of this stepper tells us:
- max voltage: 3.12V
- max current: 1.3A (this is close to the max current that the A4988 can deliver while not being overheated)
- resistance: 2.4 Ohms
- torque: 28Ncm

So look for a motor with max rated current of ca. 1.3A, 2,4 Ohms (or lower) and 0.28Nm torque (or higher).
Examples are:
17HS13-1334S, 17HS15-1684S or 17HS15-0854S

To get a better understanding of stepper motors:
http://www.machinedesign.com/motorsdrives/misconceptions-about-stepper-motors-explained

Do you have already thought about a solution yourself or is a part of the problem sitting in front of the screen?

timpep

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Re: stepper motor
« Reply #2 on: February 13, 2018, 04:35:15 PM »
Awesome
Thank You Very Much