How would I build an electric generator with variable torque? It's my understanding that P=T*rpm, but that T is const.
I am interested in retrofitting a spiinner bike to produce electricity. The spinner currently uses brake pads to adjust the resistance. There is plenty of energy being 'lost' in the form of heat due to the brakes. I would like to be able to adjust the resistance of the bike without losing energy in the form of heat.
I understand that gears are a possibility, but I would prefer to be able to adjust the resistance in a continuous manner.
I've considered a CVT (continuous variable transmission) design, but this would be quite difficult.
I've aslo wondered if the relative motion of a disk with permanent magnets to a disk of stationary coils would vary the resistance. I'm not sure what the range of variation would be however.
Any suggestions or insights you might be able to offer would be much appreciated.