brushless motor

I'v been reading a bout brushless motors, are these different from steppers?


also i am wondering about the basic types, and how to control them espically these two::

1) this one is for a RC aircraft
http://site.nitroplanes.com/exceedmotors/63M18b.jpg

Note it has 3 wires, one is power, ground, signal,?right?
what is the signal i need to run this?
Also it says it is a 3500kv brushless, that doesn't really mean what it implies?
I think I have also read that some of these go up to 40amps?? is that true? how do the batteries keep up, is that why they die so fast?

2)this is from a cd rom

http://www.wrobots.com/surplus/SSC-0EE09A.JPG

Is this one dc,I noticed a few transistors in there?
How would I power this one?
Is this a stepper motor of some sort??

thnx

3500kv means the maxiumum speed it can run at is 3500rpm/volt - ie at 10 volts it could do 35,000rpm with the right timing.

Similar to steppers, just much faster.

ok! so how do i power it? like a stepper too? or more like a servo?

Similar to a stepper in that you must energize the phases in a specific sequence. Similar to a servo in that you need to know where the rotor is so you know where you are in that sequence.

Look around some app notes like from Microchip for BLDC motors. It'll give you the idea of what it is you need to do.

OK! thnx!

so does that mean that the red + blk are vcc+gnd, and the middle is signal wire?

doggy__ said:

OK! thnx!

so does that mean that the red + blk are vcc+gnd, and the middle is signal wire?

Click to expand...

no... they run more like synchronous 3 phase AC motors, but they are optimized for trapezoidal (square wave) drive instead of sinusoidal.