I've been searching for a small (20 to 30mm Dia) disc shaped EM lock for a project I'm working on but can't find any. This type of lock's function, where when the EM is energized the magnet activates, attracting a pin or plate, is what I need it to do but I can't find them small and flat enough. I then found some 24V EM brakes for a "Duplicator" (copy machine?) where the size may be ok but if they were flatter it would be better. From what I understand these work the opposite way. The brake pad is normally engaged ("locked") to the hub by a spring, then when energized, the brake pad separates from the hub allowing it to rotate. Is this correct?
Would it be possible to convert the EM brake into an EM lock merely by reversing the wiring or would I need to reverse the direction of the winding? Would that work to then attract a plate when it is energized?
Also, how much could I reduce the voltage and have it still attract a metal plate with a decent pull strength - say from 1/4" away?
Thanks for you help!