Dual Z axis motors Problem.HELP!!!

Hello everyone!

This is my first post in here and I hope to find some answers!
One week ago, I started to built my own Prusa Mendel. Everything was right until today.
I connected the z motors and they don't rotate! I have an Arduino Mega 2560 R3 with RAMPS 1.4.
My stepper motors are NEMA 17 model 42BYGHW811 (2.5A, 1.8deg/step)
When I connect only one z motor, it rotates properly. When I connect and the second one, none is rotating although the Shield "sends" current to both of them. My very first thought was that the current is not enough. Is there any way to change the current that stepper motor driver "sends"??
Any thoughts???????

Elo

Edited 1 time(s). Last edit at 07/24/2013 07:17AM by nerovich.

Are you hooking them up in series or parallel?
There is a very small potentiometer on the stepper driver controller that allows you to adjust the current.
Are you sure you hooked the second motor up correctly in relation to the first motor?

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Hi rhmorrison.

I found out the potentiometer your are talking about and adjusted the current! It was so easy...
Thanks a lot!

Hey! Hi!

I also am new and I had the same problem, which I solved ith the same solution.

You're a life saver!

Thanks!

Going back to the first post. A 2.5 A motor is not what you want with the normal stepper drivers. Running a pair of them would take 5A (you don't want to run them in series...). Most of these drivers are doing well if they put out 1.5 amps.

I know this is an older thread, but I was wondering why you wouldn't want to connect your motors in series? I've read in many other threads that a lot of people prefer series. I'm having similar problems with a Z-axis on an ord bot and am trying to get the right set up for my z-axis motors. Thanks

It depends on the motor specs and driver specs

If you series the motors, the required voltage doubles while the current remain the same as if one motor is running. Doing it in parallel, the voltage required is still the same as running one motor but the current requirement is now doubled

So you need to think what are the voltage and current requirement of the motor and if doing either series or parallel configuration will the driver handle the load configuration?

My motors are 57 oz-in rated at 1.2A. The resistance is 1.7 ohms. Here's the link to them: [www.ebay.com]

I'm running an Ord bot hadron and am having a terrible time getting my Z motors to work correctly. Here's a video of them running on youtbue here:

[www.youtube.com]