Cg-4 mount with steppers

Thread Starter

clive22

Joined Jun 5, 2024
1
Hey guys,
I originally bought the astroeq and some steppers with the plan to 3d print brackets and belt gears similar to the plans on the site.

I picked up some steppers ( https://www.oyostepper.de/goods-17-...ähte-Kleiner-Hybrid-Bipolar-Schrittmotor.html ) and built up my mounts. First test the mount didnt move. I adjusted the current limit and managed to get the mount moving, but the steppers got so hot it started warping my plastic mounts. After reading the faq on setting current limit and getting it within spec the mount would not move again.

So I was wondering if i should look at adjusting my mount or changing my gear ratio? (currently 15 tooth on motor and 40 on mount) or should i put the steppers in the parts box for another project and buy bigger?

Side note the drive kit for the cg-4 has no problem moving the mount around.
 

MisterBill2

Joined Jan 23, 2018
27,507
There is only one reason for stepper motors getting too hot, and that is excessive current. Using the ancient classic design with 90% of the supply voltage dropped across big external resistors, but connecting without adding those series resistors will cause an overheat every time.
 

MaxHeadRoom

Joined Jul 18, 2013
30,655
No reason anymore for using a resistor in series with Stepper motor, modern drives can/should be capable of setting plate operating current according to plate rated degree.
Motor current should be maintained at this level from zero to max RPM.
 

MisterBill2

Joined Jan 23, 2018
27,507
No reason anymore for using a resistor in series with Stepper motor, modern drives can/should be capable of setting plate operating current according to plate rated degree.
Motor current should be maintained at this level from zero to max RPM.
True, but what sort of driver did the TS use?? AND the TS states that they increased the current. Also, not everybody uses the modern controls hardware.
 

MaxHeadRoom

Joined Jul 18, 2013
30,655
Also, not everybody uses the modern controls hardware.
You don't necessarily need an expensive drive, there are quite a few IC's now that are aimed at Stepper control with current control feedback etc.
A few paltry $$$'s !
If you do not design for this either way, the result will be less than stellar!
 

MisterBill2

Joined Jan 23, 2018
27,507
MY POINT WAS that we have no hint as to what sort of driver circuit that the TS used. So it could have been an older circuit or a "state of the art" circuit, and we have no clue provided. THAT was the point I was suggesting.
Consider that not everybody rushes out to buy the vary latest product.
 

MaxHeadRoom

Joined Jul 18, 2013
30,655
I don't even remember how long ago the series resistor method was in vogue, it has been so long, The IC's that cater to stepper control have been around for some time now.
L297, L298 combo for a couple of examples.
 

MisterBill2

Joined Jan 23, 2018
27,507
It was indeed a while back. BUT those old "Superior Electric" drivers were durable and the TTL chips they used were quite cheap. Mostly it was the big series resistors that failed or got broken. So they could easily be available at used electronics sellers.
OR maybe the TS just raised the current setting on a more modern driver, LIKE WAS STATED.
 
Top