Homebuilt Electric Motors

150 Watt Generator

This 12 volt, 3-phase generator is one of my latest projects.

The client needed to power high-intensity LED spotlights and other airborne equipment in model airplane drones that are being used for air reconnaissance in wildlife conservation. Typical mission duration can be up to 6 hours long, thus in-flight charging is a necessity.

The shaft of the generator is turned via a timing belt by the same 60cc petrol engine that powers the aircraft.

The generator had to be mounted in close proximity to the engine, therefore temperature was an important design concern. Potential heat-related problems were averted by using a Scorpion motor, because it employs magnets with a temperature rating of 200°C.

The 150 Watt, 12 volt generator is based on a Scorpion S-3020 brushless motor kit. The stator was wound so that charging voltage is obtained at just above idle speed.
Scorpion S-3020 brushless motor wound as 12 volt generator
Scorpion S-3020 brushless motor wound as 12 volt generator
Scorpion S-3020 3-phase generator next to DLE-60cc petrol engine
Scorpion S-3020 3-phase generator next to DLE-60cc petrol engine
Three of the drones used in wildlife conservation
Three of the drones used in wildlife conservation

Wind Generators

Over the course of the last 15 years, I've been fortunate to have been involved in the design and contstruction of a few wind generators, ranging in size from 500 Watt to 4 KiloWatt.

With my first generator project, I was thrown in the deep end to do the stator and winding design of a 4 KiloWatt "monster", relatively speaking. It was a joint effort with my flying buddy who was an armature winder. Up until then, my motor building experience was limited to rewinding some CD-ROM motors and building a couple of small outrunner motors for model aeroplanes.

With the generous help of the very knowledgeable members of the LRK Torquemax forum, many stumbling blocks were overcome or prevented.

To be able to start turning in light wind conditions, low cogging is an important requirement for a successful wind generator.

Because this was a permanent magnet generator of the "outrunner" type, the main challenge was undoubtedly to minimize cogging, which we succeeded to do very well. There was hardly any cogging noticable.
Roughly machined flux ring and some stator plates stacked
Roughly machined flux ring and some stator plates stacked
Flux ring with 50x22x8mm curved Neo magnets
Flux ring with 50x22x8mm curved Neo magnets
The parts before winding the stator and final assembly
The parts before winding the stator and final assembly
The stator wound and terminated - Note the skewed slots
The stator wound and terminated

500 Watt Wind Generator

This 500 Watt wind generator is also a recent project. With the experienced gained in previous generator projects, designing this unit was rather straight-forward. Because the generator was intended for vertical-axis installion, the exterior design was styled to be weather resistant and therefore doesn't require an enclosure.

The very low cogging torque that was achieved with this design, is a direct result of an optimum slot/pole combination and good stator design. Observant viewers will notice that the aluminium parts are not anodized. We tried to keeps costs to a minimum, because this is a prototype unit.
Trial fitting of the parts of the generator
Trial fitting of the parts of the generator
All the parts prior to winding the stator
All the parts prior to winding the stator
The stacked stator and magnets
The stacked stator and magnets