Let me first say I am VERY new to electronics, so I apologize ahead of time (I'm very active on StackOverflow.com, so I understand). I have the following components I'm attempting to control with an Arduino Uno:

  1. 42BYGHW609 NEMA 17 Stepper
  2. DQ420MA Microstep Driver
  3. 12V-36V Regulated power supply

All components are listed here: at Ebay

My question: Is it safe to connect this regulated power supply directly to my driver and the driver to my motor? The motor is rated at 1.7A and 3.3V but the driver has 12V in. Is this a safety hazard? Do I need to do something to lower the voltage to the motor or does the driver handle this?

  • 1
    \$\begingroup\$ Since it's a set, it looks like the driver provides the motor with the voltage it needs. \$\endgroup\$
    – Handoko
    Commented Jun 8, 2014 at 16:08
  • \$\begingroup\$ That's what I thought and why I decided on this kit, but before powering everything up I wanted to be sure I wasn't going to fry my equipment. \$\endgroup\$
    – alan
    Commented Jun 8, 2014 at 16:32

1 Answer 1


The stepper driver does current limiting. You can set the current limit with the dip switches. Just make sure it is set to OFF-ON-OFF (SW1-SW2-SW3) for 1.7A.

The stepper coils have a resistance of 2 Ohm, so at 1.7A they will require 3.4V. So the math seems to be correct.

PS. the power supply is actually 24V not 12V.

  • \$\begingroup\$ Awesome, thankyou so much. And yes you're correct it's a 24V, I even tested that earlier with my multimeter. So by setting those DIP switches I could potentially drive a larger stepper? Like a NEMA 23? \$\endgroup\$
    – alan
    Commented Jun 8, 2014 at 18:45
  • 1
    \$\begingroup\$ Yes, you indeed could. \$\endgroup\$
    – Gerben
    Commented Jun 8, 2014 at 19:48

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