Brushless motors are not synchronous motors. They are just brushed motors without brushess (BLDC, brushless DC motors), the brushess are replaced with a controller (an 'inverter'). The controller acts as commutator&brushes. The controller measures voltages induced in the coil/phase that not active at that time. That voltage is used to synchronise the controller to the motor (and not the other way around).
Brushless motor animations and simulations:
http://www.rcgroups.com/forums/showthread.php?t=216928
The workings of a brushless controller:
http://www.torcman.de/peterslrk/SPEEDY-BL_eng.html
One line course on magnetism, motor design and controllers:
http://www.consult-g2.com/course.html
DIY Brushless controller compilation
http://www.rcgroups.com/forums/showthread.php?t=140454
Design discussions:
http://www.rcgroups.com/forums/showthread.php?t=200567 |