I'm experimenting with a surplus simple sensorlesss friction drive unit which I obtained at low cost, with a similarly simple BLDC (sensorless) controller for my quirky Bickerton lightweight folder. I have tested motor, battery and controller successfully off the bike (see attached photo). With better weather coming I would now like to test the system on the bike, but have some concerns. 1. Firstly the controller is not equipped with overcurrent protection and the accompanying technical information suggests external fuse(s). Would the fuse be wired into the main power supply from the battery or in a phase or phases of the 3-phase supply to the motor?
2. When the friction wheel first makes contact with the tyre it is likely that a back voltage will initially be generated in the motor. How can a damaging back voltage be avoided in the controller 3-phase supply leads? If any?
3. As it stands the system will only be road legal if I put some sort of PAS onto the bike and arrange for that to turn off the motor when the pedals are not being turned. (A torque sensor would I think be over the top).
Any help on these technical issues would be much appreciated.
Best wishes
peterjd
2. When the friction wheel first makes contact with the tyre it is likely that a back voltage will initially be generated in the motor. How can a damaging back voltage be avoided in the controller 3-phase supply leads? If any?
3. As it stands the system will only be road legal if I put some sort of PAS onto the bike and arrange for that to turn off the motor when the pedals are not being turned. (A torque sensor would I think be over the top).
Any help on these technical issues would be much appreciated.
Best wishes
peterjd
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