Hub dynamo

The hub dynamo has a bicycle dynamo that is usually installed in a special hub in the front wheel.

History and Development

In 1913 Alois Sanladerer had logged out Ortenbourg a patent on a hub dynamo in the U.S. and get issued in 1914.

For the first time presented the English company Sturmey Archer hub dynamo in the 1930s, manufactures and marketed it under the name Dynohub. The production was set in England in 1984.

In recent years, the hub dynamo has evolved and is more often despite the higher price for use in Neufahrrädern he has the side Dynamo almost completely displaced. Its practicality is high because it works regardless of weather conditions and compared with the usual side runners dynamo has a high efficiency. Thus, the obstruction of the driving operation is very low due to additional force to be applied. The integration into the hub of the front wheel results in comparison to side runners Dynamos have the consequence that a workshop or a workshop- standard equipment is required for the replacement of the dynamo, despite extensive maintenance a defect should occur.

Manufacturers and designs

There are several vendors (eg, Novatec, Renak, Schmidt Maschinenbau, Shimano, SRAM, Sturmey - Archer ). There are two basic designs:

• Gearless hub dynamo Here permanent magnets produce the hub body located by the rotation of the wheel, a rotating magnetic field which induces an electric voltage in the stator winding installed in the stationary part of the hub. The lighting is switched on via a switch, which is usually integrated into the headlights, or via an electronic control, the light will automatically turn on in darkness. These dynamos have the highest efficiencies in operation, but they have in the non-energized state due to the even at idle the dynamo ( ie without closed lighting circuit ) core losses occurring low torque loss.
• A hub dynamo, which are taken via an auskoppelbares gear in the hub in operation. So there is no load loss, it is due to the higher speed of the generator smaller designs possible and it is also not an electrical switch is required. However, the efficiency is not as high as in the direct-drive, gearless hub dynamo. Advantages result from the more compact design compared to gearless hub dynamo and a resulting lower weight.

Due to its high efficiency, there is now a wider range of chargers that use the electrical energy of the hub dynamo to charge batteries, cell phones or GPS devices on the hub dynamo again.

Performance

The bicycle magazine Bicycle Quarterly has evaluated seven different hub dynamo in 2005. It was determined a reduction in speed due to the hub dynamo of about 0.1 km / h ( light off) and about 1 km / h ( light on) at speeds of 10-20 km / h. At higher speeds, the loss is less, up to 0.36 km / h difference when riding in a flat at 50 km / h