First experiment

The first of three phases (for the three phase design) was wired up and it was found that at 60 rpm the peak to peak voltage for one phase was only 2 volts. This tells me that I don't have enough coils of wire per phase. I would like to have a peak to peak voltage of about 40 volts at 60 rpm, so I am off by a factor of 20! So what do I do? I only have 5 coils per phase. If I go to a 2 phase design I can fit 12 coils of wire around the wheel per phase. I then need to increase the number of turns per coil by a factor of 8.5. I used AUG14 wire for the three phase experiment, which is very fat wire. If I use AUG24 wire I may be able to achieve the high voltage at the low rpm. The picture below illustrates how the coils could be positioned for the 2 phase design.

RPM and Hertz

There are 36 spokes in the wheel and 36 magnets. As the magnets pass the coils of wire they will produce a sinusoidal wave of induced current. If the wheel revolves once every second then there will be 18 cycles of induced current in the wires. The frequency of induced current would then be 18 Hertz. The voltage will depend on the number of turns in the wire, the velocity of the magnets relative to the coils and the efficiency of the inductive coupling. There are three phases each offset by 1/3 of a cycle. Here is a circuit model for this kind of generator charging a 12 volt battery.

Position of the coils around the wheel

This is one example of how the wire coils can be placed relative to the magnets to create three phases.

The voltage will depend on the number of turns in the coils and the rpm of the wheel.

Bicycle Wheel Generator for the VAWT

This bicycle wheel has 36 magnets fastened to the rim that correspond to the 36 spokes. The wire coils will be positioned around the edge to create a three phase PMA.