Easy Driver does not give stepper motor enough power

Hi,

I have been following Sparkfun's stepper motor tutorial to turn my 125 oz.in motor (RioRand Stepper Motor - 125 oz.in (200 steps/rev)-JK57HS51-2804). however, as I have hooked up a 12v 2A power supply, no matter how much I turn the on-board potentiometer which controls the power output, the motor always turn at very low strength (very low power), I have measured it cannot even lift up 20oz at 1in. My question is what might be the problem I have? do I need a piece of heat sink? change power supply?
This is the potentiometer

link to the tutorial that i followed
https://learn.sparkfun.com/tutorials/easy-driver-hook-up-guide

Thanks so much!
Ti

The A3967 driver chip on the EasyDriver is only capable of 750ma current/phase and your motor is spec'd at 2.8A. There's nothing you can do using that EasyDriver to get the full torque from the motor; you need a driver capable of more current.

You may find some useful stuff in Stepper Motor Basics

Post a link to the datasheet for your motor.

You need a stepper driver that can comfortably provide the current required by the motor. If the motor requires 2.8 amps I would be thinking of a 4 amp or 5 amp driver - which will be very much more expensive than an Easydriver.

…R

Have a look at this thread.
Postings 23 - 30 give you some information about a suitable driver for your project.

There are other drivers available, just compare; the recommended ones are quite reasonably priced.

Chagrin:
The A3967 driver chip on the EasyDriver is only capable of 750ma current/phase and your motor is spec'd at 2.8A. There's nothing you can do using that EasyDriver to get the full torque from the motor; you need a driver capable of more current.

2.8A is beyond a single-chip driver really. Geckodrive or similar might be the way to go,
or http://www.ti.com/tool/boost-drv8711 if
you are prepared to deal with writing some SPI code to control it.