Steppers, Series, Parallel

[Robin Hewitt]

But aren't your motors on mains voltage, or something silly high, in which case it's hardly surprising that they would overheat in parallel?

I wasn't born with them, I used lower Voltages for years then woke up one morning and found 220 Volts suddenly seemed like a good idea

And, Cor blimey, I wasn't trying to be controversial, just observing that you need twice as much power supply if you want to go in series.

But while we are on the subject of Volts and inductance I can't resist one more quick pop as I seem to have struck a nerve


If you full step the motor all the inductance has to be overcome when you step, the coil goes from full power in one direction to full power in the other.

If you half step the coil gets an off period between the two extremes and the inductance becomes less of a problem.

If go beyond half step you introduce fractional current steps reduce the current switching inductance problem even more.

Stepper heaven is to have the current in two sine waves 90 degrees out of phase, doesn't step at all, turns smoothly.

BUT... he says putting on his asbestos knickers... I have never seen a stepper turn faster than when I full step it and the inductance is hardest to overcome.

[Ricardoco]

Ok so looking at the motors and Drivers below:-


how is the final Required Motor Voltage calculated
What would the suggested setup be..
What sort of rpm could be expected.
I will be using an AC supply with the drivers.

Rick

[m_c]

32 * Sqrt inductance is the most accurate approximation. Failing that, somewhere within 4-20 times rated stepper voltage.

[Ricardoco]

32 * Sqrt inductance is the most accurate approximation. Failing that, somewhere within 4-20 times rated stepper voltage.

So 55-56v max? so what is the optimal then?

Rick

[JAZZCNC]

how is the final Required Motor Voltage calculated
What would the suggested setup be..
What sort of rpm could be expected.
I will be using an AC supply with the drivers.

Rick

I'd run them at 70V and use a DC Toroidal supply not AC. The motors "Safe" running is 55V but we know from experience they will handle 70V without any trouble so thats where I'd be running them.
Reason I'd run DC is because the capacitors handle back EMF better and deliver smoother power. Don't know these drives or the Supply your using so hard to say how they will handle any Back Emf but it's something you need to consider esp if the Gantrys heavy and you plan to run the machine fast.?