Re: [CAD_CAM_EDM_DRO] Re: Brushless motors from models and such

Due to competition rules the case size and magnets of brushed RC car
motors are strictly controlled. Therefore the number of turns is the
only 'tweakable' part. The fewer turns the faster the motor will go and
the higher the current draw. To maximise efficiency the wire size is
always the biggest that can physically fit onto the rotor for a given
number of turns. In some cases it is more efficient to wind with two or
more thin wires in parallel rather than one thick wire. For instance a
10 turn double would be 10 turns of doubled up wire. As things are so
standardised most suppliers don't bother to quote actual power figures.
Due to the very high currents and speeds these motors run at, brush life
can be very short, as low as an hour or so for high performance motors.

Brushless motors are different. As there aren't any real standards for
these yet the manufacturers often quote the Kv and Kt figures. Due to
the explosion in popularity of electric flight recently (both planes and
helicopters) there are now a huge variety of brushless motors available.
Most of these motors are rated for 10-15 minute runs but if you buy a
larger motor than you need you will be able to run it for longer.

Les

Roy J. Tellason wrote:

>Heh.
>
>Yeah, I did notice that information on them looked to be a little hard to
>come by, the one common thing on the tag on them (in a glass display case of
>all places) was "turns" -- as in how many, but not what size wire or
>anything else.
>
>
>