Failed attempt to explain JAG linearity

[Al Skierkiewicz]

Chris,
I believe we are talking the same thing. The collapsing field generates a voltage independent of the EMF of the motor. Whether caused by the FET switch or the brush assy, the pulse is very short but the path is still through the diodes and to the battery. The current flow induced is still subject to the diode forward bias and is clamped to Vbatt as Gary pointed out. If measured at the output terminal of the controller, the pulse would clamp at Vbatt+2.5 volts (the diodes forward drop). All that being said, the winding is still moving in a magnetic field and a voltage is induced in said winding but cannot exceed the supplied voltage unless an external mechanical source adds to the speed. Therefore, the EMF is not high enough to forward bias the diodes and will be something less than Vbatt when the controller is turned off. If the controller remains off, the EMF will wind down in proportion to the decreasing speed of the motor. This is fairly easy to see with a non loaded motor and a scope at the output of the controller.