Re: Stepper Motor Resonance ?

["Dean L. Hedin" <dlh2001-at-comcast.net>]

On Saturday 23 November 2002 04:45 am, Tim & Heather Smith wrote:
> Has anyone out there had any problems with resonance when driving stepper
> motors?

Definetly try freqmod.o,  makes a big improvement.  Be prepared
to spend some time tweaking emc.ini if you do.

Also,  what type of driver are you using for those steppers?
Switching to a good constant current type made a difference in my case.
The fact that this type of controller overcomes the inductive reactance of 
the motors seems to supress the resonance issue.  

Well heck, might as well do a review on my controller right now for the
benefit of the rest of the list.   Here is the one that I am using:

http://www.brewingtontech.com/

This is a pretty good deal for the EMC stepper user. 3-axis -at- $115

The specs are here : http://www.brewingtontech.com/ds3ax7026.pdf

Pros:  Low cost,  constant current, Good heatsink,  fan connection provided. 
Up to 3 amps per phase.   Nice connectors,  easy hookup.  Extra inputs
are bused for emc inputs (limit switches probe input etc...)

Cons :  Step/Dir are not on the standard emc pins.  So I cut traced/jumped 
the pcb.  The is a nice area on the board to do this.   Board does not have
"idle mode" so constant current flows even when the motors are not moving.
I accomodate this by having a switch to turn off the driver when idled (but I 
may add my own watchdog circuit to do this, should be easy)
You have to purchase a seperate high amperage 32VAC transformer to power this
controller (Brewington does not sell it).  I purchased mine from a surplus
mail order house.

Overall I am pretty happy with it.