James Dyson and the Harrier.
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PDR1
I think you are wrong.
A small bit of google research suggests to me that they are actually quite clever.
Both Ford and Mercedes make cars.
They all have 4 wheels, windows and doors.
Just as other people make "similar" motors to Dyson, there is a difference in the cars.
I think you are wrong.
A small bit of google research suggests to me that they are actually quite clever.
Both Ford and Mercedes make cars.
They all have 4 wheels, windows and doors.
Just as other people make "similar" motors to Dyson, there is a difference in the cars.
PDR 1
Your elementary look at brusless motors is correct, but you are assuming that Dyson is using motors similar to your drone propulsion.
The basic principles are the same. The detail is different.
There are, but not many in this application...
The Dyson motors only have 2 (assymetric) poles, not the 9 to 12 used in 'normal' motors and as you note use Hall Effect sensors to sense armature position.
You don't. But you do need to be clever if you want to go from zero to 100,000 RPM in 0.7s, do it as the battery is dropping in V, and do it with a motor efficiency around 90%.
Can I suggest you search and read some of Dyson's patents...?
Your elementary look at brusless motors is correct, but you are assuming that Dyson is using motors similar to your drone propulsion.
The basic principles are the same. The detail is different.
There are plenty of electric motors (especially brushless ones) which operate at these sorts of speeds.
the controller will be either a sensored or sensorless brushless controller of the kind made in gazillions al over the world - known technology and nothing particularly clever.
you don't need to do anything clever to know and govern speed because you're nailing it in the control function.
The rest of it is snake oil, of course. And purple plastic - that makes it very high tech!
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An interesting thread.
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums
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Small steps first. Before we ditch the mighty Pegasus, would a Dyson vacuum cleaner be able to supercharge my 6 pot piston banger of which there is already a variant but it uses a belt driven Eaton pump.
I think not, but just like the Harrier interior it could easily be kept sparkling clean with such an apparatus.
I think not, but just like the Harrier interior it could easily be kept sparkling clean with such an apparatus.
[quote=Nige321;9376615]PDR 1
Your elementary look at brusless motors is correct, but you are assuming that Dyson is using motors similar to your drone propulsion.
The basic principles are the same. The detail is different.
[quote]
So we're talking about a clever application, but Dyson claims it's a clever motor, which it ain't IMHO.
So you agree there's nothing inherently unique about the motor - it's a shame that Dyson't marketing pretty well all focusses on his "clever" motor, then.
The two-pole motor config is simply the standard way of getting a high motor constant (high rpm/v number). Most applications for electric moptors are seeking to do the opposite and obtain a low motor constant to get the torque to drive loads without the need for gears - hence the pole counts that go from 8 to as many as 200 poles to get Kv numbers in the more usually useful 2,000 to 100 rpm/v region. This specific application needs the opposite to get a small diameter turbine that will deliver the desired pressure/flow characteristics. It's not unique - even cheap, mass-produced commercial motors like the Mega-16EDF have two-pole configurations for similar reasons. This is not novel. Nor are kevlar/carbon wrapped rotors to provide magnet containment - these concepts have been in series production for over a decade in many places.
Getting the acceleration is simply a matter of motor power and having a controller that can track that sort of a speed ramp. 0.7secs might sound pretty fast when your normal experience is waiting for a big turbofan to respond to a throttle demand, but to a low-inertia electric motor it's quite a while, and to a microcontroller in a speed controller 700,000microseconds is a vast amount of time for doing the simple job of deciding when to switch poles on and off - especially when the chosen microcontroller has been selected to have a clock speed suited to switching poles at a bit under 2,000 times a second. These are not complicated electronic problems.
Can I suggest you do a little reading-up on the ambient state of the art in BLDC motors, and where it's been for well over a decade?
PDR
Your elementary look at brusless motors is correct, but you are assuming that Dyson is using motors similar to your drone propulsion.
The basic principles are the same. The detail is different.
[quote]
So we're talking about a clever application, but Dyson claims it's a clever motor, which it ain't IMHO.
There are, but not many in this application...
The Dyson motors only have 2 (assymetric) poles, not the 9 to 12 used in 'normal' motors and as you note use Hall Effect sensors to sense armature position.
You don't. But you do need to be clever if you want to go from zero to 100,000 RPM in 0.7s, do it as the battery is dropping in V, and do it with a motor efficiency around 90%.
Can I suggest you search and read some of Dyson's patents...?
PDR
I do feel his choice of materials in the vacuum cleaner is sub-optimal. Most of the parts are made from a plastic which is hard, but rather brittle and prone to damage in normal use - a tougher plastic would make for a more durable product. Our Dyson vac has had crack-failures several times, and now sports several epoxy-glass and epoxy-carb repair patches (the main clip area where the handle/wand attaches to the chassis cracked several times in normal use and now has a stiffening/reinforcing piece madee from 10 layers of 5-thou UD carbon cloth).
The washing machine was an excellent piece of kit which gave good service for many years. But then it did cost roughly three times the price of the competition (£900 vs £300ish) and I was disappointed when they stopped supplying spares for it - I'm not sure it has lasted long enough to justify the price premium.
Dyson's "novel" vacuum cleaner design is simply the application of industrial particle-separation technology to domestic vacuum cleaners (he even said as much in his appearance on "desert island disks" many years ago). Making it work at this scale is good engineering, but it's not brain science or rocket surgery IMHO - it's good, effective engineering rather than "genius".
PDR
Ecce Homo! Loquitur...
"Genius is one percent inspiration and ninety-nine per cent perspiration. Accordingly, a 'genius' is often merely a talented person who has done all of his or her homework."
Thomas Edison
Thomas Edison
Originally Posted by barnstormer1968
An interesting thread.
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums
Lots of comments in how clever Dyson vacuums are, or that his patents need to be looked up. Not much evidence of experience using his vacuums
I bought a superseded and imported AEG Vampyr model on eBay for £33 including postage. Original price seems to have been about €130-150
Even though it has a 2000W nominal rating, it's adjustable and set to a bit below half scale most of the time
When these limits were imminent, Dyson marketing gleefully pointed out none of its models were affected as they are less powerful. But now they are saying the new rules have drawbacks, and are proposing a new label ...
Apparently, according to Dyson, over 126 million bags and filters end up in landfill each year across the EU. I read a review that suggests that works out to £50 per home per year, though I couldn't see whether Dyson itself said this.
According to official sources there are about 27 million homes in the UK. The EU seems to add up to about 200 million homes.
Maybe Dyson and its fans should leave the brilliant maths to its engineers, rather than the marketing department.
If I spent £300 or so on a new Dyson maybe I could save about £3 a year on bags and electricity, but I already saved over £250 by buying an alternative.
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PDR
I agree about the quality of plastics used on Dyson vacuum cleaners.
My comment about experience in using them referred to people talking about patents or tech wizardry rather than real life experience.
From my own experience Dysons are far more likely to block than any other make of vacuum, and require more engineer visits than other makes.
The particularly small air/dust/dirt intake on upright Dysons is the main reason why they block so easily.
Guaranteeing no loss of suction becomes meaningless when the suction is measured within the vacuum. It has still stopped functioning as a usable tool once the intake is blocked
Perhaps the energy saving feature of brushless motors should be featured more in the sales pitch as a 'green' feature. The sales blurb on my cordless power tools always mentions longer battery life with brushless motors compared to conventional motors. It's been that way for several years now.
I agree about the quality of plastics used on Dyson vacuum cleaners.
My comment about experience in using them referred to people talking about patents or tech wizardry rather than real life experience.
From my own experience Dysons are far more likely to block than any other make of vacuum, and require more engineer visits than other makes.
The particularly small air/dust/dirt intake on upright Dysons is the main reason why they block so easily.
Guaranteeing no loss of suction becomes meaningless when the suction is measured within the vacuum. It has still stopped functioning as a usable tool once the intake is blocked
Perhaps the energy saving feature of brushless motors should be featured more in the sales pitch as a 'green' feature. The sales blurb on my cordless power tools always mentions longer battery life with brushless motors compared to conventional motors. It's been that way for several years now.
Can I suggest you do a little reading-up on the ambient state of the art in BLDC motors, and where it's been for well over a decade?
PDR
PDR
Go and find me a correctly-sized brushless motor that runs at LESS than 90% efficiency on design load and then explain why Dyson feel this is some discriminator that they can crow about in their marketing snake-oil.
PDR
PDR
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I considered the Dyson but settled on a Gtech 22V Air Ram. Great quality materials, fast recharge, and efficient and simple to use. Pricy though - fair to say I didn't have budget oversight. All in all though, a great buy that makes housework an breeze.
Having summoned up the courage to post that, shooting myself now by way of contrition is but a small step.
Having summoned up the courage to post that, shooting myself now by way of contrition is but a small step.
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Good job I don't need one but I could never afford his latest hair drier! (as featured on the BBC news tech feature last week end)
We kept a DC 04 going for years. the DC 54 replacement is rubbish in comparison.
We kept a DC 04 going for years. the DC 54 replacement is rubbish in comparison.
