You are right, I miss the photos of the coil connector, where you can see the pair of junctions of copper wire.

 

Do you think that the TS will be able to assemble a driver circuit for this motor??

You're probably right... but I don't think you would like it if someone said that about you.
It seems to me the second time you've made these kind of allusions.
Meanwhile, in this AAC thread we are collecting on a lot of information about this strange engine that cannot be found elsewhere.

 

Dyson Actually built and invented their new motors, known as Dyson Hyperdium Motors.
They are capable of speeds up to 125,000 RPM hence the small compact rotor.
They operate on a very high speed double pulse system.

I would think it is going to involve a very high frequency pulse generator, and by the size of those stator windings, the current is going to be HIGH. !

Hi @MaxHeadRoom,
what mean double pulse system? Two different frequencies on the same signal?
When you tell very high frequency what order of magnitude you think?
And when you tell about HIGH current.. In your opinion how many A?

I don't know if with a motor in the middle the things are much more complicate,
but I remember the Vacuum Cleaner was about 200W.
If the battery is 22V... maybe we are around 10A or similar?

 

Meanwhile, in this AAC thread we are collecting on a lot of information about this strange engine that cannot be found elsewhere.

While not a small very high speed motor the SRM is quite alive and well. A lot of mining machines use them and some cars use them in the electronic power steering. A SRM is one of the very first electric motors invented, way back in 1838. "The first patent was by W. H. Taylor in 1838" from https://en.wikipedia.org/wiki/Switched_reluctance_motor#References

 

You're probably right... but I don't think you would like it if someone said that about you.

He doesn't like it, he calls it "throwing stones" when you show him wrong.

 

Hi @MaxHeadRoom,
what mean double pulse system? Two different frequencies on the same signal?
When you tell very high frequency what order of magnitude you think?
And when you tell about HIGH current.. In your opinion how many A?

I don't know if with a motor in the middle the things are much more complicate,
but I remember the Vacuum Cleaner was about 200W.
If the battery is 22V... maybe we are around 10A or similar?

I meant an alternating pulses between the two windings, The frequency has to be in the order of what ever the required RPM has been selected, which as you can see is very high.
The diameter of the windings indicate a high current but probably very low voltage.

 

While not a small very high speed motor the SRM is quite alive and well. A lot of mining machines use them and some cars use them in the electronic power steering. A SRM is one of the very first electric motors invented, way back in 1838. "The first patent was by W. H. Taylor in 1838" from https://en.wikipedia.org/wiki/Switched_reluctance_motor#References

You're right, but I didn't mean SRMs in general, I meant precisely this engine here.
If you search you'll see that someone has tried to study it... but in my opinion this thread already reach more information than all the others put together.

 

I meant an alternating pulses between the two windings, The frequency has to be in the order of what ever the required RPM has been selected, which as you can see is very high.
The diameter of the windings indicate a high current but probably very low voltage.

Thanks.
Do you have some suggestion in terms of numbers (Hz/kHz/MHz? - 1/2/10/100A? - 1/5/10/20V?) and waveform?

 

It is hard to speculate at this point, they seem to have gone in a completely new direction on this motor.
Obviously at 250,000 revs, there must be some Very high switching techniques circuits involved!

 

Which devices are the switching transistors? That is a question of some importance so that we can see them and estimate the ratings. And I assumed that "Double pulse" meant two pulses with one shorter spacing followed by a longer space then two more closely spaced pulses. That sequence instead of a constant distance between pulses.

 

It is hard to speculate at this point, they seem to have gone in a completely new direction on this motor.
Obviously at 250,000 revs, there must be some Very high switching techniques circuits involved!

Thanks.
But from where come out 250 KRPM? Maybe I lost something in the entire thread.
I don't remember exactly where I read, but I think this motor max performance is around 100 KRPM.

Ciao

 

I understand it to mean that a motor of this deign is Capable of 250krpm.

 

It is not at all clear as to why this conversation is wandering off into the realm of theoretical high speeds.It is not likely to ever happen with this collection of parts and pieces. Given the large number of small parts attached to a small PCB it would be a challenge for a master technician to replace whatever parts have failed, even if they were known and the replacement was actually available.
And as the original fault happened during some form of experimentation for some unclear purpose, why

 

It's now clear from the post #41 pics that the two coils are in parallel and will generate opposite polarity magnetic poles, as expected.

I think this motor max performance is around 100 KRPM

For argument's sake, let's assume 120k rpm. That's 2k rps. So as the rotor has only two poles the coils would be switching polarity at 2kHz I reckon. That should be a stroll in the park for a modern MOSFET-based H-bridge.
If the motor is indeed rated at 200W then, as said, that implies an average 10A current draw.
The battery pack label states the capacity as 30Wh, so at 200W the battery discharge time would be ~9 minutes. Is that reasonable?

 

It's now clear from the post #41 pics that the two coils are in parallel and will generate opposite polarity magnetic poles, as expected.

For argument's sake, let's assume 120k rpm. That's 2k rps. So as the rotor has only two poles the coils would be switching polarity at 2kHz I reckon. That should be a stroll in the park for a modern MOSFET-based H-bridge.
If the motor is indeed rated at 200W then, as said, that implies an average 10A current draw.
The battery pack label states the capacity as 30Wh, so at 200W the battery discharge time would be ~9 minutes. Is that reasonable?

@Alec_t, I totally agree with your analysis.
Also the time of battery discharge seems to me realistic, when activated at maximum power.

So, if I understand well we are supposing that providing enough current (order of magnitude 10A) to the coils, the shaft will turn one time by 180° (depending by the polarity applied).
Then if we switch polarity quickly and continuously, in the order of 2 kHz, we can expect to see it rotating.
I like it.

At next step I will try to map exactly for any polarity applied the resulting magnetic verse.
Then, we can see if the shaft can turn of 180° providing enough current.
I will let you know.

Ciao

 

. So as the rotor has only two poles the coils would be switching polarity at 2kHz I reckon.

If your getting your two rotor poles from the drawing given a few posts ago, that wasn't for this motor. A tow pole SRM will not be self starting, it would need a spin by hand to get it going. And the electromagnetic poles don't need to be different phases in a SRM. A SRM is different than any other motor you have ever studied, the rotor poles have no magnetic properties, like a winding or permanent magnets. The SRM works totally on the stator coils attracting the ferrous poles on the rotor.

The one thing different in thhis motor is it only has two stator pole which should mean it only has one phase. Most SRM's have 3 or 4 phases. A link to a good explanation of SRM's - https://www.intechopen.com/chapters/55670

 

If your getting your two rotor poles from the drawing given a few posts ago

We weren't. See post #24. I don't believe this motor is mainly SR in operation; it's mainly BLDC in my opinion because of the neodymium magnet rotor.

 

Then if we switch polarity quickly and continuously, in the order of 2 kHz, we can expect to see it rotating.

Eventually, yes. You would have to work up to that frequency from zero, to allow the rotor to accelerate. The Hall sensor, correctly positioned, would trigger a microcontroller to switch polarity. The devil is probably in the control detail. I imagine that, because of the rotary inertia, timing may depend on rpm, much as ignition timing needs advancing in a combustion engine. All that electronics in the Dyson appliance must be doing something more though (unless it's just there for obfuscation ). Perhaps it's for regenerative braking and battery charging?

we can see if the shaft can turn of 180° providing enough current.

If my theory is correct about the angular offset of the rotor's rest position, I think applying say ~100mA DC in one polarity would be enough to cause the rotor to move just a few degrees in one direction; ~100mA DC in the other polarity (once the rotor had returned to its rest position) would move the rotor through nearly 180 degrees in the opposite direction.

 

Regenerative braking on a vacuum cleaner????? I sort of doubt it.

 

I sort of doubt it.

So do I. So what do you think all that electronics would be doing in a vac?