Motor Movement

Hello,

I have assembled a RepRap Prusa Mendel i2. I am stuck up with the electonics, Please Help !

Im using a 450W , 12V SMPS.
NEMA 17 and POLOLU A4988.

The motors were revolving all fine in the start. But, after a couple of runs, the motors move and stop, move and stop.
This process continues, for all the three motors whenever i give an input in pronterface.

For Example, If i give an input of 10 towards positive x direction, The motors move towards +x like :
Move ( 2 steps ) STOP Move (2steps) STOP ...... And then this continues till it completes the 10 steps.
The movement is not continuous. There are regular stops.

Please Help .
Thanks !

Sounds like your stepper drivers are over heating. Do you have cooling (heatsinks and a fan) on them?

Did you set the voltage reference on each driver? I've run two printers with A4988 drivers with just heatsinks and had no problems and I now run the DRV8825 without heatsinks or fans and they run fine but I am always running at 70% of max current of the motor.

Thanks for the quick reply.

But, I have a cooling sink on them, and i am working in an air conditioned lab. So, I guess heating should not be a problem.

I have tried varying the voltage between the trim pot and the ground of the power supply in the range of 0.4 V to 0.8V
But still, the situation is the same.

What do you exactly mean by 70% of max current of the motor ? Could you please explain the setting procedure for that ?

Quote
Bharadwaj
I have tried varying the voltage between the trim pot and the ground of the power supply in the range of 0.4 V to 0.8V
But still, the situation is the same.

What do you exactly mean by 70% of max current of the motor ? Could you please explain the setting procedure for that ?

Only follow this if you have the Pololu A4988, otherwise you need to find the value for your sensing resistors.

http://reprap.org/wiki/Pololu_stepper_driver_board#Tuning_motor_current

Sorry for being so late.,

The problem is set. I changed the power supply.
I use a 12V 30Ah Power Supply now, and everything is working fine.