Contactless motor drive

[cio74]

Hello,

Does anyone have any documentation about a contacless motor drive, not sure about terminology. The idea is to have the electromagnetical field generated in a separate piece and the rotor in other. Therefore, one piece can stay in a box while the other outside. Inside the box there are no electrical wires.

Here is a commercial example of such product, however it does not fit my needs and I'd like to build my own.

Thanks.

[Conrad Hoffman]

That looks similar to magnetic lab stirrers. The motor has a magnet attached to the shaft and spins whatever needs to be spun via a magnet attached to that. Google "magnetic stirrer diagram" and you'll see various configurations. There are other ways to accomplish this, but the magnet is easiest.

[Zero999]

You've not stated any requirements so you won't get much help.

An aquarium pump typically uses a synchronous motor with a permanent magnet rotor. The stator is is sealed and potted in resin so and the magnet is built-into the impeller which forms the rotor.
http://en.wikipedia.org/wiki/Synchronous_motor

[mags]

Many brushless motors have this kind of topology, with fixed coils on the outside and a rotating permanent magnet.
Seal-less pumps add a waterproof membrane between the two.
So a brushless motor drive chip might be useful to you. I've never used one myself, but believe that it will help with things like commutation, where it can sense back-emfs in the coils and use them to automatically compute the angular position, and hence commutate the device (fire each coil at the correct time).
Otherwise you'll need an additional commutation system (e.g. optical)

[IanB]

Does anyone have any documentation about a contacless motor drive, not sure about terminology. The idea is to have the electromagnetical field generated in a separate piece and the rotor in other.

The terminology is "induction motor". The world is full of them, ranging from tiny fan and disk drive motors in PCs, through drum motors in tumble driers, up to really huge industrial motors.

All induction motors require some kind of AC to drive them, either from the mains, or electronically generated and controlled.

The motors are most efficient when the gap between the rotor and stator is tiny as this provides the best magnetic coupling. However, with a bigger gap some kind of hermetic seal can be provided that completely isolates the rotor environment from the stator environment, for example when pumping corrosive or hazardous fluids.

As mentioned above, laboratory stirrers and aquarium pumps both work on this principle.