Hello all,
let me start by saying that I only have a little hobbystic knowledge in the field of electronics and electrical engineering.
But I'm becoming passionate about this topic below.

Trying to modify my old Dyson DC35 Multifloor to work with a power supply, I burned out the controller during my testing. Patience.

So, I recovered at least the motor body, without electronics on board.
And now I wonder... how could I make it work, even if not to its full functionality?

The motor looks like this (assembled)


The rotor have an embedded neodymium magnet on the shaft:


and the magnetic stator is detachable and composed by two "electromagnets" in which terminals (T1 and T2) seems designed to be always in opposition of polarity:


Coils are done by a thick copper wire.
So, there are only 2 contacts and I think that applying DC current (any of the polarities) both "electromagnets" are always active and always opposite (N/S).

If I measure the resistance of the coil with multimeter, I obtain 0.1 ohm.
It is not a professional multimeter, so I have tried to apply a little voltage (0.1 V) and my power supply tell me about 1.25 A:

so, I think that a value of 0.08-0.1 ohm is realistic.

I've tryed to apply an oscilloscope and turn the shaft manually, I obtain this:


At the moment I am unable to do any other experiment, because my power supply is not able to provide more current (MAX 5A).
But I plan to use some high power resistor in series (i am purchasing it), like that:


in order to be able to play.

Looking at the waveform on the oscilloscope, I think that providing a power AC signal (sinusoidal or even also squared?) able to alternate polarity of the to electromagnets, i can obtain some turn.

I will update here with my next steps.

Meanwhile I do some experiments (and hoping not to blow up the house!) I'd like to ask if someone of you have ever seen this kind of motor (brushless with 2 contacts) and if it is possible to suggest me some commercial ESC controller or other kind of driver able to run it.

Thanks in advance.
Frank

 

Hi, Is the motor originally powered by 240 volts AC (UK)?
Good luck........

 

Hi, Is the motor originally powered by 240 volts AC (UK)?
Good luck........

Hello twohats, no, it is powered by 22.2V battery.
In-fact I have burned some logic in the controller making experiments to power it with a lab-power supply.

 

Those coils do not get fed with DC, that is for certain. And there is a whole lot that we do not see with the pictures of that motor, that is certain. Do you still have the damaged circuit board to show us some pictures of it? Because what I see is only a small part of a motor. There is a lot not shown. And I am not willing to spend time with only part of the information.

 

The rotation speed is directly related to the frequency applied to the coils. The waveform cannot be a squarewave, because alternating squarewaves do not produce torque, which is required to get the shaft moving. A shaped waveform is required to produce torque. At the normal rpm of this motor, the drive frequency will be so high that coil inductance will be much more involved than coil resistance when it comes to establishing the current. Much more iformation is required regarding the normally-supplied frequency and current before you can make any progress.

 

This teardown may be informative, looks like the motor drive circuitry is non-trivial.

https://www.experimental-engineering.co.uk/2016/03/03/dyson-dc35-digital-teardown/

 

The circuit to drive the coils so that the motor will provide the speed and torque adequate for the vacuum to function correctly will need to provide a drive power similar to what the original circuit provided. If you still have the damaged motor controller it may be that a repair is possible.. We do not know what power was provided, nor what frequency was provided. Without that information how can a replacement be designed????

 

Hello all,
this is the burned controller board.

FRONT:


BACK:


It is funny that, making these pictures, I see a candidate for the role of the "burned component"... a component that doesn't look good...

SIDE:


So, when I have some time I will try to recognize what component is that.

But, I can remember that when the controller was working, if the connector "A" in the first picture was not connected with the other two boards of the cleaner (1-the start/stop button board and 2-the battery charger inside the battery body), the motor does not start.
Instead, the connector "B" seems only related to the speed: if you detach it from a working DC35, simply it will run always at maximum speed.

When I burn the controller, I was triyng to understand how to bypass the block induced by connector "A" missing presence.

Wishing a pleasant day to you all,
Francesco

 

What is clear to me after seeing this board is that there is a whole lot to the functioning. A 20 leg IC and three of the 6-leg ICs, plus a lot of other parts. So duplicating that functioning will not be simple at all.

 

Hi all,
after having bought a board based on OPA541 and having burned it even before trying to use it on the Dyson motor, I tried to build myself the device that is summarized here (Signal Generator Amplifier DIY).
Now I think I can do some experiments on the Dyson, providing it with various waveforms/frequencies.

Even if I couldn't get it to rotate well, just making it spring into motion would be enough.

Does anyone have any suggestions on what shape and frequency to experiment with?
And maybe also on how to connect it... I had measured a coil resistance between 0.08 and 0.1 ohm.
I was thinking of putting a 5ohm 100W resistor in series with the coil to lower the required current a little, but I don't know if what I say is heresy.

I wouldn't know where to start.

Someone have some experience about how to drive a "switched reluctance motor" with just 2 connectors?

 

How does the TS propose to know where to connect a drive signal to that circuit board. And how did we get pictures of oscilloscope traces from one who incinerates circuit boards?" And why think that a drive frequency comes via a connector, when it is probably a digital interface?
To be able to correctly connect to a circuit board for a motor driver one much knoe a bit about what is connected to those pins on the connector. Randomly connecting to pins is not likely to result in anything except more burned boards.

 

How does the TS propose to know where to connect a drive signal to that circuit board. And how did we get pictures of oscilloscope traces from one who incinerates circuit boards?" And why think that a drive frequency comes via a connector, when it is probably a digital interface?
To be able to correctly connect to a circuit board for a motor driver one much knoe a bit about what is connected to those pins on the connector. Randomly connecting to pins is not likely to result in anything except more burned boards.

I am not sure to understand the aim of your answer.
Are you suggesting to ignore my questions because for you I am not enough skilled and I make stupid errors?

 

My point is that there is a serious need for information prior to any action. This means knowing how the system works, as far as signals on connectors. Looking at the other circuit boards that have the controls on them would be a way to learn what comes from a control and where it connects to.
So my aim is to provide the push to gain information as to just what the circuits are and what sort of signals are required to provide the results you seek. And also to convince you that randomly applying signals is not likely to make anything work. Knowing what signal goes to which pin will allow a chance of success.

 

My point is that there is a serious need for information prior to any action. This means knowing how the system works, as far as signals on connectors. Looking at the other circuit boards that have the controls on them would be a way to learn what comes from a control and where it connects to.
So my aim is to provide the push to gain information as to just what the circuits are and what sort of signals are required to provide the results you seek. And also to convince you that randomly applying signals is not likely to make anything work. Knowing what signal goes to which pin will allow a chance of success.

Thanks for clarification.
Let me be more clear: the controller is burned and there is no information in internet about how these Dyson motors works (or maybe i was unable to find it).
My will is to forgot the controller and, looking only at as the motor appear (see the first post) try to experiment some way to make it move - maybe not well, maybe not 100% efficient, but move.
There is no digital pin or something like that: just the 2 connectors on the motor.
Seems there is a lot of people intersted, but as far as I know, no one have done someting succesfully.
Also seems to me a good hobbistic target - the other chance for me is to trash bin the motor - why don't play with it?
I hope now the idea sould me more clear.

 

OK, drive the motor with an adjustable switchmode buck converter power supply. If it is a DC motor that will work. BUT if if is a brushless DC motor then a motor driver is required. But with only two wires, probably not brushless.
For motor testing, a DC power supply is what you need, connected to the motor terminals. But going back to post #1, it is not a brush type motor, but some sort of AC motor driven by the now destroyed driver board. So there must be more to the motor than the pictures we see show us.
IS the rotating core magnetic? Or is it possibly an induction motor??

 

It is definitely not a DC motor IMO, BLDC maybe, both stator and rotor have neodymium type magnets.
It appears to be a simple 2 pole type, which will posses the highest RPM out of any other pole count motor of this type.
Never an induction motor with Permanent magnets!

 

It is definitely not a DC motor IMO, BLDC maybe, both stator and rotor have neodymium type magnets.
It appears to be a simple 2 pole type, which will posses the highest RPM out of any other pole count motor of this type.
Never an induction motor with Permanent magnets!

The type of motor and the mechanism of it's operation is a puzzle, Max. How does a motor with only one set of windings and only two terminals and apparently only two poles, generate torque?? I am aware of shaded pole motors, which seem to have a similar physical arrangement. The photos in post #1 do not provide nearly enough detail to enable a conclusion as to how the magnetic fields work. The permanent magnets were a guess of mine, that perhaps it is a shaded pole synchronous motor, which can actually rotate quite well with a single coil.

 

Those Dysons use a switched reluctance motor not a bldc.

The electric motor marketed as the Dyson Digital Motor (DDM) is a direct current motor, operating on the switched reluctance principle. From - https://en.wikipedia.org/wiki/List_of_Dyson_products

 

, that perhaps it is a shaded pole synchronous motor, which can actually rotate quite well with a single coil.

A shaded pole motor is not synchronous, but asynchronous, very inefficient due to its heat producing shorted turn.
Also it could never reach the required RPM for a vacuum cleaner.

 

The rotor have an embedded neodymium magnet on the shaft:

How many poles does the magnet have? (You may be able to tell from the 'cogging' felt as you rotate the shaft).