Stepper motors & vma03 shield power

Hello everyone,

I am very new to this game so please don't be offended by any of the following possibly stupid things I might say.

I recently obtained an arduino uno R3 coupled with a vma03 motor&power shield see and two steppermotors
for details on the hardware:
vma03
steppers

The motors respond like they should when I connect the USB, but they lack power when I put them in place. They are used for two rotating platforms, directly connected to the axels and intended to work at a low speed. the weight of the platforms shouldn't be a problem; 7mm MDF board 30cm diameter.

So i figured the stepper motor driver has to powered as well. But when I connect both USB (or the DC input) to the UNO and a direct power supply (DC 12v 1500mA) to the Vma03: the motors are spinning faster, leds are brighter and the driver gets really hot!

The datasheet tells me that the max input of the vma03 is 50v, Do I have to worry about frying the driver with a 12v input??

However the motors can only take 3v. And I'm not sure if the driver limits the current?

If anyone has any ideas on how to properly supply these things of power, on alternatives for the driver (pololu a4988?) , motors (higher voltage?, it needs to deliver at low speed), it would be highly appreciated! And my gratitude would be eternal.
Or if this construction is doomed to fail in any other way, please share your insights!

Thanks in advance.

Best,
Raf

Have a look at stepper motor basics.

Those motors require 2.5amps which is well beyond the capacity of the hobby stepper drivers such as the A4988 or DRV8825. They need a more powerful stepper driver capable of supplying 3 amps or more.

That type of h-bridge shield is a very poor choice for any stepper motor and quite unsuitable for the motors you have.

...R

Hi Robbin, thanks for your reply!
So a solution could be to look for a stepper motor which requires less amps? within the capacity of drivers like you mentioned?

rvdv:
So a solution could be to look for a stepper motor which requires less amps? within the capacity of drivers like you mentioned?

Yes, if you want to be able to use the lower priced drivers. But there is no use buying a motor that is not powerful enough just so it can work with cheaper drivers.

Strictly speaking the proper order of events is

  • work out the torque required for the application
  • identify a motor that can produce enough torque (allow a good margin of error)
  • find a driver that will suit that motor

...R

So if i where to combine for instance the polulu A4988 which is capable of providing 1.5A per coil, and the following motor: 42BYGHW804 -> http://www.wantmotor.com/ProductsView.asp?id=155&pid=80
which rates at 1.2A, the problem would be solved? The holding torque is slightly less on this engine, but still within the margins I believe..

That motor should work well with the A4988. I have no idea whether it would be suitable for your application.
The Pololu DRV8825 is rated up to 2.2Amps if you think you need a more powerful motor.

…R