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bogflap
27-06-2009, 10:17 AM
Just seen adverts for the latest Dyson vacuum cleaner. Claims to use a motor that spins at an rpm of 100k. This seems like an ideal motor for powering a routing spindle for isolation routing of pcb's. I am starting this thread simply to invite comments about the motor as and when they become available. Or maybe I am hoping that someone out there will get hold of one, take it to pieces and let us all know what it looks like from the inside. Also does it live up to the rotational claims?, what bearings does it use?, how easy is it to mount in a diy build, ...

John S
27-06-2009, 11:14 AM
Only thing I can see with this is it's going to be a largish motor to run an engraving spindle.
There have been great strides made lately in the small motors in respect to RC aircraft.

Have you looked at some of these options ?

Gary
27-06-2009, 11:25 AM
These motors are not designed to have any radial or actual loads, and if they are like motors that i have seen from other manufactures, they dont have a shaft that you can use to connect your tool to.




Just seen adverts for the latest Dyson vacuum cleaner. Claims to use a motor that spins at an rpm of 100k. This seems like an ideal motor for powering a routing spindle for isolation routing of pcb's. I am starting this thread simply to invite comments about the motor as and when they become available. Or maybe I am hoping that someone out there will get hold of one, take it to pieces and let us all know what it looks like from the inside. Also does it live up to the rotational claims?, what bearings does it use?, how easy is it to mount in a diy build, ...

BillTodd
27-06-2009, 01:48 PM
I suspect that the main disadvantages of using this motor (i.e. bought as a spare part from Dyson) would be the difficulty of driving another spindle without buggering-up the dyson bearings and the very limited starting torque produced by this type of motor; It looks to me to be a single phase variable reluctance motor [edit - It's not it's just a brushless DC motor - I missed the bit about the neodyium magnet]. The start routine will be a hit & miss process i.e. apply a pulse, detect movement, test if it's spinning it the desired direction - correct if necessary with next pulse, then sync the pulses etc.

If you attach a spindle, the extra drag of AC bearing (for instance) might prevent the motor from starting at all.

From Dyson's POV the main advantage must be manufacturing cost (although their plant looks more like a small volume operation than a proper production line - I love the robot arm coil winder :))

I suspect you'd be better of sticking with a poly-phase permanent magnet motor as used in model aircraft (I've seen 1kW motors for ~30, and 12v controllers for them aren't much more)

bogflap
27-06-2009, 05:01 PM
My current thinking on this is

1) The Dyson gizomos are hand held so I am presuming that the motor is not that big, ok so biggish compared to a RC aircraft motor

2) Looking at the complete setup required for an RC aircraft motor; an ESC (Electronic speed Control) is required; a PSU (Power Supply Unit) is required that is very none standard, last time I investigated I assumed that LiPo voltages (7.2 volt?) were required at a some enormous currents (60amps?)

3) Taking into account above then cost wise the Dyson looks relatively cheap

4) Taking into account the above maybe that motor may not be so large


Only thing I can see with this is it's going to be a largish motor to run an engraving spindle.
There have been great strides made lately in the small motors in respect to RC aircraft.

Have you looked at some of these options ?

bogflap
27-06-2009, 08:53 PM
Basically pcb isolation routing is going about about 2mil deep into what is basically GRP (Glass Reinforced Plastic) or resin. The radial and axial forces are minimal/very small. Oh and plus about 35micron of copper. Forces are small, speed is the must. If the bearings can hold up blowing air in a residential environment with what, at least a years warranty, then they stand a chance with isolation routing that requires short of nothing by the way of radial/axial forces.

I have no associations with Dyson nor wish any. Fast and cheap is what I am looking for.



These motors are not designed to have any radial or actual loads, and if they are like motors that i have seen from other manufactures, they dont have a shaft that you can use to connect your tool to.

bogflap
27-06-2009, 08:59 PM
I agree. That robot arm is something else.


I suspect that the main disadvantages of using this motor (i.e. bought as a spare part from Dyson) would be the difficulty of driving another spindle without buggering-up the dyson bearings and the very limited starting torque produced by this type of motor; It looks to me to be a single phase variable reluctance motor [edit - It's not it's just a brushless DC motor - I missed the bit about the neodyium magnet]. The start routine will be a hit & miss process i.e. apply a pulse, detect movement, test if it's spinning it the desired direction - correct if necessary with next pulse, then sync the pulses etc.

If you attach a spindle, the extra drag of AC bearing (for instance) might prevent the motor from starting at all.

From Dyson's POV the main advantage must be manufacturing cost (although their plant looks more like a small volume operation than a proper production line - I love the robot arm coil winder :))

I suspect you'd be better of sticking with a poly-phase permanent magnet motor as used in model aircraft (I've seen 1kW motors for ~30, and 12v controllers for them aren't much more)

Phil Gravett
04-07-2009, 11:59 AM
Why don't you router guys use comp air drives ? With the Desouter one I had which was very light, you could with a 1/8th carbide burr hold a piece of mild steel in one hand and cut through it. The exaust whilst a bit noisy could be used to blow swarf away. Phil. :idea:

templecorran
20-07-2009, 01:57 PM
I had the main bearing on my router burn out (literally) after about 100 hours running. So my point is that the duty cycle for the Dyson may be short. How long does your PCB 'etching' typically take to run? I realise it depends on the amount of material to be removed. Compare that to the time it takes to vacuum the floors that the Dyson is designed for.

John S
20-07-2009, 02:02 PM
What CFM compressor is required? most DIY "Router guys" wont have the luxury of a 200ltr receiver and 18CFM hydrovane units....Not to mention sympathetic neighbours :naughty: :idea:

My hydrovane is only 10 CFM :thumbdown:

Mind you I do have two of them :whistle:

Gary
20-07-2009, 02:13 PM
What about these for PCB drilling / routing?

http://www.slidesandballscrews.com/brushless-motors-c-75.html

Some have integrated electronics, and some are high speed and are continuously rated.
We also have torque curves.

Gary
20-07-2009, 04:39 PM
There are verity of speeds and the datasheets do match, what you need to look at is the nominal speed not the max speed.
As an example there is a motor that has a max speed of 20000 RPM, but at that speed the torque is very low, but at 12000 RPM, the torque is at its highest and this is the speed we rate the motor at.
this is the misconception a lot of people have.
If a motor has a max speed of 20000 RPM, does not mean that you can get the most power at that speed because torque drops as speed goes up.



I looked at those a few days back Gary...are they 12.000rpm or 20.000rpm? datasheet and description don't match :confused:

Gary
20-07-2009, 05:30 PM
That is like saying a SY60 is a 800 RPM motor.
In this case the motor is at its most powerful at 12KRPM, but will quite happliy run at 20KRPM, but not at the same torque or power.


Oh cool....so it's a 12.000rpm motor...

Gary
20-07-2009, 06:40 PM
Shit? compared to what? The datasheet lists a no load speed, and surely you realize that this is not the rated speed of the motor?

Speed is propotional to Voltage and Torque is propotional to current, and the curve shows the continuous rating.

Just like other DC motors, you can get more torque at the higher speeds, but you will be limited due to heat, and the heat will effect the duty cycle.






Nah it's equivalent to saying "here's a 20.000rpm motor but it's shit above 12k"

Gary
20-07-2009, 06:49 PM
When you buy a servo motor that has a nominal speed of 3000 RPM, but a max speed of 5000 RPM, do you call it a 5000 RPM motor, no you call it a servo motor.
Why? because the speed is varible, and not fixed.

Gary
20-07-2009, 07:52 PM
Who said it was a 20000 RPM motor?
The description doesn’t, the specification only mentioned the no load speed.
In fact the motor is not a 12000 RPM motor, but it will do 12000 RPM continuous at the torque specified inthe torque curve, just like it will do 20000 RPM at the speed is shows in the curve.
The only person who made the misguided assumption that it was 20000 RPM was you, and then claimed it was crap becasue the power at 20000 RPM was not as you expected.
These motors have a variable speed and are designed to be used throughout this speed range, so the torque curves are there to show what you will get at a specific speed.
Show me an AC induction motor manufacture that offers a speed curve?
They don’t offer them because they rate their motors at a known speed.
When you buy a AC induction motor and you ask for a 2800 RPM motor they will sell you a 2 pole motor, but the speed may not be 2800 RPM, and generally varies by about 150 RPM due to slip, but this does not mean that the motor is faulty it is just the design of the motor.
Would you send it back if you were getting 2734 RPM if you run it at 50hz? no you wouldn’t.






When I buy a 2800 RPM motor I expect a 2800 RPM motor....No semantics just what I want.

Gary
20-07-2009, 09:08 PM
You made the assumption not me, i was just pointing out your assumption was wrong.

bogflap
21-07-2009, 08:24 AM
Having started to look at bearings for high speed operations it looks like your burn out after a 100 hours may well be 'par for the course'. I looked at angular contact bearings with rated speeds of up to 200,000 rpm (phew!) and when you take into account preloading and cooling and lubricants and distortion of the shells due to centrifugal force, blah, blah, blah then 100 hours is 'par for the course'. Anyway back to the Dyson motor. If it contains bearings that will stand up to a 100 hours usage (which lets face it, for say a years warranty is ball park reasonable to expect) then maybe the motor is worth consideration.

I had the main bearing on my router burn out (literally) after about 100 hours running. So my point is that the duty cycle for the Dyson may be short. How long does your PCB 'etching' typically take to run? I realise it depends on the amount of material to be removed. Compare that to the time it takes to vacuum the floors that the Dyson is designed for.

bogflap
21-07-2009, 08:44 AM
Have seriously looked at compressed air and yes the speeds are impressive. But in this thread I was simply posing the possibilities of using the Dyson motor. I just love 'bleeding edge' technology if indeed that is what the Dyson offering represents.

Why don't you router guys use comp air drives ? With the Desouter one I had which was very light, you could with a 1/8th carbide burr hold a piece of mild steel in one hand and cut through it. The exaust whilst a bit noisy could be used to blow swarf away. Phil. :idea:

bogflap
21-07-2009, 08:59 AM
All good stuff but it is speed I am looking at. A Dremel tops out at 33,000 rpm, no load, and I consider that a little pedestrian.
Ok so gear things up but using something like belt drives at high rpm involves tensioners and even then at high speeds perceived internet wisdom seems to think that belts stretch, slip, burn out, skip out of grooves, become unbalanced, 'become complicated'. Gears seem to suffer a similar perceived status of 'complicated'. At the moment my thinking is that direct drive is the way to go but I am still very much open to persuasion and/or reasoned argument

What about these for PCB drilling / routing?

http://www.slidesandballscrews.com/brushless-motors-c-75.html

Some have integrated electronics, and some are high speed and are continuously rated.
We also have torque curves.

Gary
21-07-2009, 09:26 AM
What speed and torque are you after?
the fastest we offer has a no load speed of 43000 rpm.
I have seen small motors run faster, but they were induction motors specially made for drilling applications like dental drills, but they can be expensive.
These were made by http://www.airbearings.co.uk and they can offer speeds of up to 300000 RPM.
but at these speeds expect to pay a lot and will also use air bearings



All good stuff but it is speed I am looking at. A Dremel tops out at 33,000 rpm, no load, and I consider that a little pedestrian.
Ok so gear things up but using something like belt drives at high rpm involves tensioners and even then at high speeds perceived internet wisdom seems to think that belts stretch, slip, burn out, skip out of grooves, become unbalanced, 'become complicated'. Gears seem to suffer a similar perceived status of 'complicated'. At the moment my thinking is that direct drive is the way to go but I am still very much open to persuasion and/or reasoned argument

templecorran
21-07-2009, 11:03 AM
Having started to look at bearings for high speed operations it looks like your burn out after a 100 hours may well be 'par for the course'. I looked at angular contact bearings with rated speeds of up to 200,000 rpm (phew!) and when you take into account preloading and cooling and lubricants and distortion of the shells due to centrifugal force, blah, blah, blah then 100 hours is 'par for the course'. Anyway back to the Dyson motor. If it contains bearings that will stand up to a 100 hours usage (which lets face it, for say a years warranty is ball park reasonable to expect) then maybe the motor is worth consideration.

Excuse me, My point had to do with the expected life of the motor under the conditions it was designed to be used in, verses the life expectancy of the application to which is suggested in this thread. In practice the component that fails is the bearing at the business end of the motor.

I modified the base of a B&Q 1020W router (25) for use as my RockCliff spindle. After more than 100 hours of use, my router ground to a halt with a failed bearing. I was somewhat surprised when looking for a replacement that the 6003ZZ bearings are typically rated for 22000 RPM in grease and 28000 in oil. The max speed for the router is 34000!.

I've attached the 3d dxf of the modified base for your amusement. Please don't ask for g code. My final design removed material around the base to lighten it considerably.

I better stop here -- this is getting waay off topic!