cnc

[jakejones]

building a cnc lath just got the contorler but it is to small for the seppersmotors i have. is there a way to get more current like using a darlinton.the driver chip is a MC3479
its 200 ma i think.or is there a driver that can handle more current.

 

[dknguyen]

Is it meant to drive the motor? Or is it meant to drive the large power transistors that are meant to drive the motor? I'm not sure if the terms driver and controller differentiate between the two or if they are interchangeable. So I will use the terms motor controller and gate driver.

The gate driver just drives the gates of the power transistors meant to deal directly with the higher power currents of the motor, while a driver is a controller and the power transistors in one. I might have it backwards or the terms might be interchangeable.

If it's a motor controller you are meant to hook up power transistors up to it. If it's a driver, then you probably can't rearrange the external wires in any way to connect to larger power transistors to drive the stepper (since there are probably less motor wires than power transistors needed).

I didn't bother to look, but my impression is what you have is a gate driver (well not a bare bones gate driver but a glorified one with extra functionality meant specifically to drive motor power transistors.)

 

[picasm]

The MC3479 is designed to drive small stepper motors directly. Probably not worth trying to increase current with any modifications.

You need to check what type of stepper motors (Bipolar or Unipolar) you have and build or buy a driver to suit them and their power requirements.

Here is a good site with plenty of links to drivers to build or buy:

For a Bipolar driver to build:
https://www.fromorbit.com/
For a Unipolar driver:

 

[Pommie]

Perhaps you should have a look at CNC Zone. Lots of very knowledgeable people over there.

Mike.