Quote Originally Posted by fkirons View Post
I've play around with similar concepts in the past and in all my experiences, attracting poles will always win when motor is off because the pole of the magnet attached to the swivel arm will force the oposite pole of magnet thats concentrically attached to the motor to spin and line up with opposite pole from swivel arm. Therefore needle will retract. For I can see this machine should behave the same way unless there is something different going on from what I can tell from the video.
Exactly. John's machines have the armature bar on top and the same forces regarding polarity pull the needle down, leaving the needle exposed. Here it pulls it up retracting the needle.