Maximum stepper motor power with Smartstep/3?

[milton d]

I'm doing a long run of parts with a 1996 MicroMill (converted to lathe use) which has a Smartstep/3 controller. Martin Ironmonger of Denford was kind enough to hook me up with a good used Smartstep for a fair price which will be kept as a spare until the project is completed in March. The original board's bridge rectifier died but I was able to replace it and continue the job. I was afraid it might die again so the spare was obtained. Murphy says if you have a spare, the original part most likely won't fail.

When the job is finished, I want to reconfigure the MicroMill for mill use and build or modify another small lathe for CNC use utilizing the spare Smartstep board. I found a spec sheet for it which says the following:

"The SmartStep/3 controller is a programmable computer designed specifically for the control of 3 independent stepper axes, integrated with a power supply and three small bipolar stepper drives, as a single compact unit. The drives provide 2A per phase at 40V in half step mode, which makes the system suitable for many frame size 23 and 34 motors.

18-28VAC input or 24-40VDC input, onboard power supply provides all other voltages required."

The stepper motors the mill came with are Vexta PH266-E1.2, 2 Phase, 1.2A, 5 ohms. I'd like to use more powerful stepper motors but not overload the controller, keeping in mind that it will be driving only 2 motors. I will also add additional mass/area to the driver heatsink and add a dedicated cooling fan based on the heat induced failure of the original. Do any of you experienced CNC/electronics gurus have any recommendations as to the stepper motor specs (voltage/amperage/ohms) I should look for that would be safe to use? I'm guessing the same controller was used on other Denford machines of that era and were equipped with more powerful stepper motors.

Thanks for looking,
Milton

[Denford Admin]

I would say that the stepper motors we use now on microstepping drives (and the old baldor built in drivers) are good for turning and milling with 5 to 12mm pitch screws.
We use Motion Control Products Ltd M57STH51-2008S-2
Something similar is here:
https://www.motioncontrolproducts.com/mo ... .php?cat=1

[milton d]

Thank you very much; that gives me something to work with.