5 phase stepper motors?

[knotlogic]

I was at a surplus store over the weekend and found a stepper motor specced at 0.45 deg/step.  Figured it might be worth picking up as I've been toying with the idea of having a play with a CNC system.  But taking a closer look, it had 10 leads coming out the end.  A quick google search revealed that there are such things as 5 phase steppers.  I'm not sure if this really is one though.  The only material I found on the net says that the 5 phase models run at 0.72 deg/step, which isn't a nice multiple of 0.45 deg/step.  Also, I gave the shaft a turn and found that it turned easily, with no cogging - completely different from steppers I've handled before.

Assuming it really is a 5 phase stepper, anyone know if I'd need a special driver for steppers like these?  I'd really rather not try to build my own given how many options are already out there for stepper motors.

[Nusa]

Yes, 5-phase motors need 5-phase drivers. For a hobbyist, what's available tends to be quite expensive, although you might get lucky on the used market.

[MrAl]

Hi,

5 phases is a lot of phases to have to handle :-)
This is probably more aimed at a commercial product than a hobby project.  Even the two coil steppers are a lot to handle for someone that just wants to connect a battery to a motor and have it turn.

10 wires i guess means 5 coils, each which really has to be driven with an H bridge really.
There is a prototype 'shield' made for Arduino that has two H bridges per chip with two chips,so that is four H bridges.  One more and you have five so maybe you can start with that.

The chips they use are the 293D chips or something like that, which have H bridges built in.  If you got 3 of these chips that would mean you have 6 H bridges, more than enough.  Check the data sheets first though to verify the number of H bridges on the chips you might use and make sure you have enough.   Check the current ratings also.

[CM800]

if it's 5 wires.



if it's 10 wires. (equally you could likely wire them together to look like the first picture.)


https://www.autonics.com/index.php sell some.

[MrAl]

Hi,

Yes the 5 phases can be wired up to two H bridges and a single half bridge.  That makes the circuitry simpler.

[knotlogic]

if it's 5 wires.



if it's 10 wires. (equally you could likely wire them together to look like the first picture.)


https://www.autonics.com/index.php sell some.

Thanks. What's odd though is that second image says 0.72 or 0.36 deg/step.  The units I saw were definitely labeled 0.45 deg/step.  Unless they weren't actually 5 phase steppers and had extra wires for some reason.

I'm almost tempted to get one just to play around with it.  Juggling too many things right now though, so that would be bad.

One other thing I don't get is in that diagram showing the phase pattern on a 5 wire device, how would we energise neighbouring coils in the same direction?  Sure we could apply the voltage across 2 or more at the same time, but that also split the applied voltage across each.  I'm probably missing something very obvious...