# Too much mass on stepper motor? It wont spin!

I have a 12V/350mA bipolar stepper motor from Adafruit: http://www.adafruit.com/products/324 I have a Arduino motor shield attached on top of the Arduino; this motor shield uses the LM298 driver, which can output 2A max per channel, according to data sheet. However, due to the huge mass (20 in Al motor shaft + attached PCBs; very heavy stuff) on top of the motor shaft, the motor is no longer turning, and I have to slowly push it w/ my hand to get it to turn step by step. My power supply (from Agilent) is 24V/0.5A. Do I need a larger power supply? All I'm doing is trying to make motor spin back+forth using the Stepper.h library. How do I make this motor turn? Do I need a motor w/ a higher current rating (up to 2A)?

Edit: I have 1 more question-- is there any way to adjust the acceleration of the bipolar stepper motor on the Arduino code? I know I can adjust speed using "myStepper.setSpeed(200)", where 200 = 200 rpm.

and I have to slowly push it w/ my hand to get it to turn step by step

Does that mean that it runs, and keeps going, after you give it an "assist"? If so, that's a clue. Going from a body at rest to a body in motion takes a lot of work. A better-rated supply (or some SLA batteries) may prove beneficial.

Not quite-- it's still at rest no matter what I do. I've tried a different power supply (from 24V to 32V) for the motor. I've tried pushing it, but it's still at rest. I know it's trying to move, because I see the 4 LED lights at the 4 outputs are flashing and there's a lot of audible motor noise.

Clown_of_God: Edit: I have 1 more question-- is there any way to adjust the acceleration of the bipolar stepper motor on the Arduino code? I know I can adjust speed using "myStepper.setSpeed(200)", where 200 = 200 rpm.

http://www.open.com.au/mikem/arduino/AccelStepper/

C_o_G, I think sourcing a stronger motor is your best bet.

My power supply (from Agilent) is 24V/0.5A. Do I need a larger power supply?

Yes

By the way your name is the title of a book that was my kids favorite bed time story.

I figured it out-- the motor was a bad motor. It was stuck even w/ all the load removed. Replaced the motor and everything worked.