Hub dynamo and Related Topics

Sturmey-Archer

Manufacturing company originally from Nottingham, England.

The internals of a Sturmey Archer FM four-speed, medium ratio, hub gear. It has substantially more components than an AW 3 speed. FC, AF, AC, and ASC hubs are similar.

Exploded View & Parts List of Type SW three-speed Mk. 1. Sturmey-Archer Gears Ltd., 1954

The Dynohub was Sturmey-Archer's hub dynamo (generator) for bicycles.

Dynamo

Electrical generator that creates direct current using a commutator.

The Faraday disk was the first electric generator. The horseshoe-shaped magnet (A) created a magnetic field through the disk (D). When the disk was turned, this induced an electric current radially outward from the center toward the rim. The current flowed out through the sliding spring contact m (connected to B') through the external circuit, and back through B to the center of the disk through the axle

Hippolyte Pixii's dynamo. The commutator is located on the shaft below the spinning magnet

The Woolrich Electrical Generator in Thinktank, Birmingham

Low voltage dynamo for electroplating from the turn of the century. The resistance of the commutator contacts causes inefficiency in low voltage, high current machines like this, requiring a huge elaborate commutator. This machine generated 7 volts at 310 amps.

A small electrical generator built into the hub of a bicycle wheel to power lights is called a hub dynamo, although these are invariably AC devices, and are actually magnetos.

U.S. NRC image of a modern steam turbine generator (STG).

Electric generator

Device that converts motive power into electric power for use in an external circuit.

Early Ganz Generator in Zwevegem, West Flanders, Belgium

This large belt-driven high-current dynamo produced 310 amperes at 7 volts. Dynamos are no longer used due to the size and complexity of the commutator needed for high power applications.

Ferranti alternating current generator, c. 1900.

A small early 1900s 75 kVA direct-driven power station AC alternator, with a separate belt-driven exciter generator.

The Athlone Power Station in Cape Town, South Africa

Hydroelectric power station at Gabčíkovo Dam, Slovakia

Hydroelectric power station at Glen Canyon Dam, Page, Arizona

Protesters at Occupy Wall Street using bicycles connected to a motor and one-way diode to charge batteries for their electronics

There are two common kinds of generator in use on bicycles: bottle dynamos which engage the bicycle's tire on an as-needed basis, and hub dynamos which are directly attached to the bicycle's drive train.

Bicycle lighting

Illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination.

Early bicycle lighting: candle lamps, oil lamps and carbide lamps

Early bicycle lamps and two early bottle dynamos (1935)

A home-made HID light assembly consisting of a 10 watt HID light (right) and a 30 watt HID light (left) as well as three 1 watt Luxeon high power LEDs

A group of amateur cyclists during a night ride in Chișinău. The great majority of the participants have their front light devices enabled, but only the most powerful ones are visible on the asphalt. The street lights provide a sufficiently bright light, thus reducing the lighting equipment role to being observable in traffic.

Rear LED light mounted on the seatpost of a road bicycle

Dismantled bottle dynamo. Left: Housing with internal permanent magnet rotating through the friction wheel. Right: Induction coil

An illuminated bicycle jacket made out of clear vinyl, fiber optics, LEDs, and Christmas Lights that improves rider visibility

Hub dynamos are built into the front or rear wheel hub. These are generally the most reliable and most efficient of the three types.

Bottle dynamo

Small electrical generator for bicycles employed to power a bicycle's lights.

Two other dynamo systems used on bicycles are hub dynamos and bottom bracket dynamos.

An opafiets, a single speed traditional Dutch roadster with double top tube and coaster brake

Roadster (bicycle)

Type of utility bicycle once common worldwide, and still common in Asia, Africa, Latin America, and some parts of Europe.

The Dutch omafiets is a ladies' roadster of classic design

Three-speed 1971 Raleigh Superbe sports roadster with 26-inch tires and Dynohub

Roadsters are known in East Africa as Black Mambas, and are often used as cycle taxis or boda-bodas.

A British ad from 1897 showing a ladies' bicycle/roadster

Farmer on roadster bicycle used for freight in Indonesia

An {{lang|nl|opafiets}} or {{lang|nl|stadsfiets}} is a traditional Dutch gent's roadster

A 2012 Sohrab roadster manufactured in Pakistan

Modern Batavus roadster with Nexus hub and roller brake

The classic gents' roadster, AKA the English roadster, has a lugged brazed steel diamond frame, rod-actuated brakes and of late, cable operated drum brake systems have been widely produced for the European market, upright North Road handlebars, a single gear ratio or three- or five-speed hub gears, a chaincase, steel mudguards, steel cranks, 28 x (ISO 635) wheels, Westwood rims, and often a Sturmey-Archer hub dynamo.

Vélib'

Large-scale public bicycle sharing system in Paris, France.

A Vélib station with its distinctive grey bicycles.

Bike attachment points at a Vélib' station.

A Vélib bicycle rack with nearly all its bicycles taken.

Vélib' bikes are equipped with a locking system, a front basket and always-on LED lighting powered by a front-hub dynamo.

Shimano Nexus

Nexus front hub with attached roller brake.

Shimano Nexus is a brand of bicycle components which includes products such as epicyclical gear hubs, cranksets, shifters, brake levers, hub brakes, hub dynamos, and a CPU for automatically changing gears.