Smart Drive motor as a motor 'and' as a generator?

I was thinking of using a four-phase stepper as resolver.  I read an article on this topic years and years ago and cannot find it.  A four-phase step motor sequence uses two signals (bipolar, unipolar is just a winding trick) that are ninety degrees out-of-phase.  The RF community refers to these as quadrature signals.  They use them for detection at much higher rates, which they can because they are not using moving parts.  These are square waves if we are full stepping. They are sinuate if we are micro-stepping. 

The author connected the two coils to a resistor, on the order of the nominal coil resistance, if recall serves.  He also shunted them with back-to-back Zeners to clamp any spikes.  He used a comparator circuit to suss the signum of a step signal if he received one.  This interrupted the processor.  He had an image of the next anticipated step in memory.  If the signal conformed to this, he new he had taken another step, updated his count and image.  If not, he knew a backward step had been taken, decremented his step, and inverted his image of the next step and toggled his direction flag.  If recall serves.  I don't remember how he set up his initial configuration, or if he had to.

I guess I don't understand why it needs a separate generator mode when most of the drives you will run it with can do regeneration.  If you need the separate mode just to prove it's regenerating energy, just put an current meter in series with the phases (or the input bus) and show the direction of current changed.

Edit: I was assuming you were running the motor and then switching to generator mode to brake it, if that is not the case, then using the regen braking of a motor drive might not directly fit the application for you

Hi Michael

There are three wires into/out of the motor for power and 5 for the hall sensors.  Here is a pic of it without the hall sensors.

Cheers

Hi

I was not aware that the driver could handle the regen mode, hence why I was looking to 'externally' manage generation. 

What I need to do is start the unit as a motor and run it until it syncs with the energy input (wind turbine or surrogate), then I turn off the motor and it will run as a generator, continuing to spin, and generate power, thereby demonstrating its function as a generator.  If I can show that the generator is, in fact, generating power (or works under load) then this proves my concept, and I can move on.

Does that make it clearer and does that help you decide if I can use the regen mode of a drive, or should I stick with my original plan which was to disconnect the 'motor' externally and switch to a generator mode.

Thanks

Thanks Don,

Is the method you suggested going to be possible with the motor I have already selected?  As mentioned it is too late to change to another motor/generator system as everything is built around the smart drive specs.

Are you able to tell me how to load a pdf in this forum, because then I could load up the article I have, and perhaps you and others can review this and then suggest suitable parts?

Thanks

Here are some brushless drives that are 230VAC and take hall effect inputs. They do regen.  Not sure how well they'd do with your motor if it has strange windings.  You could always talk to their apps engineer and he might be able to help you out

PML Series

Hi

Thanks for the link.  I have sent them an email with some of my data, so hopefully they can suggest something.

In the meantime, I hope there might be a cheaper suggestion. 

Thanks again.

It's still there as a digital edition, or contact the publisher (Jude).

From what I can tell, they aren't extremely powerful, but the fact they could easily control them, and they didn't need a gearbox, was what made them popular.

My understanding of mechanics suggest that any time you have a gearbox you lose efficiency, that why they reconfigure these for the required voltage rather than try to change the speed.

However I don't know your final design/plan so I'm sure you will have it sorted.

We use an ASCO phase detection system on our generators, that when the phases match, it switches the load.

Once they match they don't change as the smaller generator has trouble driving the much larger generation system.

Mark

This picture doesn't correspond well with your spec showing different restances for phases. It looks like a traditional 3 phase multipole winding. Do you have a controller (or better still a schmeatic of one) from a washing machine.

If it's a simple 3 phase winding it's not (that) hard to make a controller but you would do better to buy one.

MK