View Full Version : Leaving your steppers on.

08-11-2003, 10:33 AM
Ever since I got my router to shut off with an M5, I let the machine cut away while I am back in the house.

When the router stops, the power is still on to the steppers (with no rotation).

I want to know if I am wearing out the steppers or the IC chips (I am using UNC5804's) by leaving the power on to them.

Also, am I correct that would not be a problem with servos?


08-11-2003, 09:22 PM
Don't know the effect on stepper but on my system, power to motor are cut-off after 5 minutes of no activity. I use a simple microcontroller for that.

08-12-2003, 10:41 AM
That sounds like a good way to do it, if you know how.

I have been looking at microcontroller information (like basic stamp), but I still need to learn more about them. Can you suggest a good source for learning how to do this.

How do you turn your power back on?


08-12-2003, 01:14 PM
Steppers get quite hot when left on with no rotation. It's a good idea to shut the machine down some how. On my machine g02 disabled the motors (turbocnc) via the enable/disable pin.

On servos the motors don't get near as warm, as they just draw enough current to sit there and "hunt" around the position between two encoder pulses. Still, I find it wastes energy, and the gecko's stay warm, so I shut it off when I get a chance.


08-12-2003, 03:47 PM
I think it might depend on your particular set up. I leave my machine in idle for hours at a time and the motors never loose position, or get more than slightly warm to the touch.

Also, a warm motor means nothing. The steppers I use are rated to 143c or 284 degrees fahrenheit. As long as you don't exceed the rating, you shouldn't be doing any damage.

08-12-2003, 04:43 PM
Steppers are like power resistors right...? They're not hot if you don't touch 'em right? ;)

08-12-2003, 05:36 PM
Originally posted by anoel
Steppers are like power resistors right...? They're not hot if you don't touch 'em right? ;)

LoL :D

08-12-2003, 09:22 PM

I just looked at UCN5804 datasheet. The chip has Output Enable pin so why not connect it to one of the parallel port pin and have the software disable the steppers (as done by Eric).

I'm basically doing the same thing as above but the enable/disable is connected to microcontroller (which is also translating step/dir to proper switching and current limits) for my driver.

08-12-2003, 09:30 PM

As for microcontroller, I've been using PIC (www.microchip.com) for years now. BasicStamp, which uses PIC, is easier to use as you program in BASIC and does not requires a separate programmer. If you are interested in PIC, visit www.piclist.com for some pointers.
Best of luck.