How It Works

Direct drive generators, used e.g. in wind turbines, need a lot of torque in order to spin the rotor of their generator. Their rotor is powered via a single axis which carries almost the full weight of the rotor (picture 1A).

A Prometheus Wind Generator is a horizontal axial flux generator powered by for instance a wind turbine (picture 1B). The weight of the generator's rotor is carried by one of more wheel trains and a pivot  / axis. The number of wheel trains and the number of wheels vary with the diameter of the rotor.

The wind turbine drives the generator's rotor via a bezel gear, a gear drive and a pin rack fitted on the outer circumference of the rotor (picture 1B).

By driving the rotor this way, the amount of torque needed to spin the generator's rotor might be significantly reduced.

Picture 1 - Weight distribution conventional direct drive generator vs. Prometheus Wind Generator
Picture shows the difference between a conventional direct drive wind generator and the Prometheus Wind Generator

Picture 2, 3 and 4 might help to understand picture 1B. They successively show the stator and rotor of a small, conventional axial flux generator (a.k.a pancake generator) powered via an axis, and a pin gear driving a pin rack. In picture 1B the pin gear is powered by the wind turbine.

Picture 2  - Stator Picture 3 - Rotor Picture 4 - Pin gear drive
Stator of an axial flux generator
Rotor of an axial flux generator Pin gear driviing a pin rack
Source pictures 2 and 3:
Source picture 4: ?

Energy Potential Indication

The video below shows a fuel truck on a turntable (picture6) powered by a pin gear drive. The video description says:"Platform for truck in Algeciras, Spain, able to move a mass of 80 tons with only 1 kw of power".


The truck on the turntable weighs about 7000 kg.

Direct drive wind turbines require about 1000 kg of permanent magnets* in order to generate 1 megawatt. 

* Weight data  of a 2,25 MW Wind Turbine Generator

Source: Page 9 of Anoop_Thesis_Final.pdf

If the turntable can carry a 7000 kg truck it can also carry 7000 kg of permanent magnets.

Imagine the turntable is the rotor of the Prometheus Wind Generator in picture 1B. Its turbine would only have to produce the  torque equivalent of 1 kW in order start the rotor spinning.

The turntable's rotation speed is 0,25 rpm. Direct drive wind turbines have an average rotation speed of about 20 rpm. If 1 kW is enough to spin the rotor at 0,25 rpm does that mean it would take the torque equivalent of 4 kW to spin it at 1 rpm and the torque equivalent of 80 kW to spin the rotor at 20 rpm? Plausible?.

Maybe, maybe not, but using an 1 kW electric pin gear (picture 5) powered by solar energy, to reduce starting torque even more seems very plausible. It might enable large direct drive wind generators to be more efficient at variable wind speeds.

Picture 5 - Wind turbine driving Prometheus Wind Generator (double wheel train + electric starter)
Prometheus Wind Generator rotor on a double wheel train using a 1 kW starter engine

Picture 6 - Cross-section view of a car turntable

Cross-section view of a a car turntable
Picture 6 shows how the turntable in the video works. The turntable in the video probably uses two ro more wheel trains.


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This page is an abstract of a previous, more comprehensive attempt to describe the Prometheus Wind Generator. Click here to read it.