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Driving to the future
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14/08/2003
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One of the most active areas of development is electric motors and drives. Tom Shelley reviews the last three years of British innovation in this market
The world increasingly runs on electricity, which is why advances in efficiency and performance of electric motors, actuators and drives occupy the minds of a large number of engineers in the UK and throughout the world.
One of the more extraordinary ideas to be reported in Eureka was Simon Powell's PBT 2D, folded strip, piezeoelectric actuator motor, the subject of our March 2002 cover story. Simon Powell writes, "I am currently in Japan sorting out suppliers for the ceramics and a range of new actuators, including the 2D device. Things have gone a bit mad right now, so we have had to delay the motor's introduction whilst we launch the world's first electronic cooker/boiler valve (due out November), the world's first piezo operated door lock (due out January) and the world's first firearm interlock to prevent unauthorised use of handguns (mid 2004). The 2D actuator has found application in the door lock. The first version has a single actuator, but by using the 2D we get a lock that cannot be vibrated open by hammer drills etc., because the unlocking motion is a function of both actuators."
Even more extraordinary, however, is Roger Shawyer's reactionless Emdrive, reported in December 2002, which uses a relativistic effect to produce thrust in a spacecraft without need for propellant. We hesitated about running the story, since at first sight it seemed to defy the laws of physics, but then decided that it doesn't. While it is not quite ready for space, or even more importantly, to lift vehicles above the ground so they need neither wheels, wings nor rotors, we are pleased to report that it still looks promising. Shawyer writes: "The Smart feasibility study was successfully completed and a full technical report produced. This was independently reviewed and issued to the DTI. They are currently considering a proposal for the development phase. The theoretical analysis has been completed and now includes a treatment of the mechanism of kinetic energy transfer. A paper has been submitted for publication. Further analysis of the experimental data has concluded that the pulsed thrust measurements can only be due to momentum transfer from the EM wave and therefore confirm that the experimental thruster is working according to theory.
"An extrapolation of the theory has been carried out for high thrust engines and the concept appears feasible. Initial design work on a lift engine has been undertaken. Some exciting commercial developments are in progress which will support a major development programme, whilst hopefully retaining the key work within the UK. "
Slightly more down to earth, we would be wrong to ignore two sets of developments that have figured prominently in our pages. The continuing developments in the very successful Control Techniques' Unidrive, subject of a Eureka cover story in March 1997 and the Brook Hansen 'W' series motors, world leaders in efficient motor technology with all the benefits that go with it.
Pointers
* The folded strip 2D actuator motor has found application in a high security door lock that cannot be vibrated open
* The reactionless Emdrive looks as if it really is going to take off
* UK advances in AC motor and drive efficiencies are proving to be of great economic benefit to customers
Simon Powell
Roger Shawyer
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Author
Tom Shelley
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