Here is one you are sure to like: http://www.pololu.com/catalog/product/2502

Bill:

I have looked at the part and the schematics and do not see how this

applies to a stepper motor.  The current capacity is certainly enough.

What am I missing?

Charlie Enz

Darn,  I completely missed that you were interested in Stepper Motor interfaces.  My bad.

http://www.pololu.com/catalog/category/120  lists the stepper drivers available on that web site.

2 amp seems to be the limit on their stuff.  What kind of monster stepper do you have that needs more than two amps per coil?

Bill:

I have a 2120 ounce inch stepper current draw is 3.3 amps/phase.  Frame

size 23, 1/4 inch diameter shaft.  Could the item you suggested be used

with resistors in series with the motor coils and a Polulu 2 amp stepper

driver driving the inputs?  If so, what would the schematic look like?

Don't worry about the misunderstanding.  Anyone who can frankly admit he

made an error has established his integrity in my mind and deserves both my

respect and trust.

Best wishes - Charlie Enz

Bill:

The previous e-mail should have said 210 ounce inches

Charlie Enz

I think you need to be looking for a traditional bridge with discrete components to drive something that thirsty.  I found some  "digital" power FETs on ebay that can source a lot of current.  They are advertised as

Fairchild HUF76107P3 MOSFET 20 AMP 30 VOLT  (Arduino motor control).

That may not be the voltage range you looking for so I found a design for a CNC mill that uses 100V 12A MOSFET.  You can take a look at it here: http://www.instructables.com/id/Easy-to-build-CNC-Mill-Stepper-Motor-and-Driver-ci/

Bill:

I made a mistake the correct torque is 210 ounce inches.  Is it possible

that the board you initially recommended could be driven by a Polulu 2 amp

stepper driver?  If so, how should they be connected?

Thank you - Charlie Enz

Bill:

I made a mistake the correct torque is 210 ounce inches.  Is it possible

that the board you initially recommended could be driven by a Polulu 2 amp

stepper driver?  If so, how should they be connected?

Thank you - Charlie Enz

Hello Charles,

     I had a bit of time just now to work on your request for assistance.  Although I do not know much about the subject in detail, it does fall into the general topic of mechatronics which is my chosen vocation.  Therefore, on eBay UK I stumbled across this beauty.  Which naturally leads one to an inquiry at google.com.  So there you go and I hope you can locate a suitable supplier for your CW5045 if that is what you believe will serve you best.   The most enlightening bit of info that you and anyone using stepper motor like yours for CNC machines should read and understand is found in this excellent post.  If I were you I might make an effort to chat with Pololu.com tech support about their 2 amp stepper motor controller.  Best of luck and I want to thank you for the opportunity to be useful.