Speed of the Nanotec ST5709S1208-B

Just got my motors working and have found, them to be very slow. I could count the RPM.. if i waited

is this right? or have i got something wrong?

yeah, i cant get much above 100RPM out of them. i think this is due to the high precision. my 200 step motors can easily do 250 RPM, and forrests motors that are like 15 steps can do much higher RPM.

i think there is a speed/precision tradeoff involved.

I'm getting a maximum of about 1200 rpm or 480 steps/sec with mine. Thats about the maximum speed I can run it at and still get any useful torque.

Of course, I am doing 15 degree steps and am using a small stepper that only pulls .44 amps/phase instead of those big boys you guys are using.

Hi Barry and Zach,

it's the step-frequency what counts - 'oldstyle' stepper IC's like the 3479P drives normal motors with fullstep at 500 to 700Hz with max. 700mA current.

My full/halfstep-controllers from ISEL are capable of running until 10000Hz, but my motors in the CNC stalls when over 8000Hz, but with microstepping i'm able to drive them over 10000hz too ...

It's depending from the step-angle, the effective mass you have to move and from the current/power you apply.

With an old Isel-controller with 2Amps at 40 Volts i was able to drive my first CNC with 4000Hz max., the same motors with my actual were driven with chopper-pulses until 6Amps at 70Volts with 8000hz, so doubled the speed (and the noise too).

So it's not the RPM what counts, but the step-rate per second, the accuracy per step and the moving and holding force or the stall-limit.

Viktor

Thank you all for the reply,
I am now informed, and will keep building.

BarryGlen.

... an update: i calculated and tested with my CNC-mill - with 8kHz in freerun i can move the CNC-axes with up to 100mm/s, what's very fast, because i have some kilograms to move!

The motors are turning max. with 1200rpm (or 20rps) with 5mm translation per turn and i have a positioning accuracy of 12,5 microns per step (with halfstepping 400 steps/turn).

When milling i reduce the speed dependant of the material and mill-diameter sometimes down to 3mm/s, but mostly it's something between 20mm/s and 5mm/s with mills from 3mm to 0,5mm diameter ...

Viktor

interesting and informative as usual viktor.

question: if you were designing a protocol and one of the parameters it had to pass was the speed to move the motor, what would be the idea units for that? for steppers? for something that could be driving either steppers or servos?

Hi Zach,

when calculating my paths or predefining milling parameters i count steps per second with steppers or millimeters per second in general.

For the tripod-controlling i have to convert the cartesian defined path (as outputted from the host-software) in short pieces and translate the angular displacement of the both endpoints in stepcounts which the three parallel aligned motors have to run to perform the bending of the struts.

So my main-unit is the single step of the motor.

I think with servos you can simply use the discrete counts of the encoder, so it should behave in the same manor.

Then you have to decide, which dimension is easier - in my CNC i have actually 12,5 microns per (half-) step or 3,125 microns per microstep, in the tripod i have a higher accuracy (but this is to change with the next setup)

I have often to convert from 'steps per second' in 'millimeters per second' or vice versa ...

Viktor