stepper motor problem

[armess]

I have a stepper motor driver in which i am using TIP122 to drive a 1Amp 2 phase unipolar stepper motor.
Due to the less torque provided by the motor i need to change it to another one. The new motor is asking for 2Amp per phase. What modification do i need to do in my circuit?
I am not using a microcontroller in the circuit and i don't want to use a heat sink.
Can somebody plz help me on this...................

 

[Nigel Goodwin]

Probably none?, the TIP is certainly rated for enough current - it depends on how hot they get?.

What voltage are you runing the motor from?, and what is is rated at? - it's normal to run them at a MUCH higher voltage, with current limiting - this gives higher speeds and more power.

 

[Mike - K8LH]

Listen to Nigel. He knows what he's talking about (most of the time, grin)...

Seriously, I had a similar problem with some 5v/1a NEMA 23 motors. I finally ended up running them from a hefty 12v/5a source with 5 watt current limiting resistors.

You might also consider "torque stepping" the motors by energizing two coils each step instead of one coil. This provides the same number of steps and doubles the current requirements but it provides a significant amount of additional torque.

Good luck with your project. Mike

 

[armess]

That means that i should use the same motor and try and increase the voltage and current driving it????
Plz suggest.

 

[Nigel Goodwin]

That means that i should use the same motor and try and increase the voltage and current driving it????
Plz suggest.

Not the current, use a higher voltage and limit the current - commonly large wirewound resistors are used for this. If you google for "stepper motor tutorial" you can find plenty about it.