I’m bored evidently.
The Dyson adverts on TV got me thinking: they go on about a Dyson Digital Motor. It sounded like bollocks; marketing fluff, so I asked them, and to their credit they answered:
Our digital motors different from regular motors in that they do not contain carbon bristles that create motion within the motor. Regular motors function by way of these carbon bristles allowing certain parts of the motor to rotate, but the use of this equipment can be noisy, heavy and produce fumes. Dyson opt for a digital motor that employs electronics and magnetic equipment to create power and motion within their machines with digital equipment inside the motor than controls the levels of power being produced by the machine. This more advanced design allows for a more powerful motor that is not only lighter, but more efficient in the long term and quieter when functioning.
So, it’s a brushless motor, with some control electronics. Maybe not marketing fluff after all. A quick google reveals this article in electronics weekly– so there really is some clever engineering- the digital bit is a microproccessor switching the supply quickly in order to make the brushless motor work on DC at very high speed. I take it back- not marketing fluff, and full marks to Dyson for answering tedious little queries.
A bit more googling reveals this press release (.doc, 35k) from 2003 with some details of an earlier version. Love the diagnostics…