View Single Post
Old Nov 26, 2012, 12:22 PM
Brutus1967 is online now
Find More Posts by Brutus1967
I convince things to work
The Netherlands
Joined Nov 2009
4,620 Posts
Quote:
Originally Posted by jasmine2501 View Post
You're thinking of the induction motor I think.

A coreless motor is the same as any other brushed motor. Remember making a motor with a nail and winding wire around it? If you pulled out the nail and left only the windings, that would be a coreless motor. It is more efficient because of lower rotating mass.
No.... I am definitely not thinking of an induction motor.... that is a completely different thing that needs 2 or 3 phase AC to run, the rotating magnetic field in the stator windings create inducted eddy currents in the weak-iron rotor, and indeed, the rotor then forms a conductor carrying a current and subject to a magnetic field.

If you coil a wire (core or not) you are creating an electromagnet. A straight wire however is not a coil, and does not create a traditional bipolar magnetic field when carrying a current, but still a magnetic field does exert a force on that conductor if a current passes through it.

Of course a coreless motor is a brushed motor, because the static field magnet has North and South magnetic poles. Without brushes the wire being forced to the left when passing one side of the fieldmagnet, would be experiencing a counterforce when passing the other side of the magnet. So you still need a form of commutation.

In the pictures in post #2 you can clearly see that the copper wires are all straightened and parallel in the area where they are subject to the magnetic field of the stator magnet.

Brgds, Bert
Brutus1967 is online now Find More Posts by Brutus1967
Reply With Quote