A generator can also be driven by human muscle power, for example, in field radio station equipment. Human powered direct current generators are commercially available, and have been the project of some DIY enthusiasts. Typically operated by means of pedal power, a converted bicycle trainer, or a foot pump, such generators can be practically used to charge batteries, and in some cases are designed with an integral inverter. The average adult could generate about 125-200 watts on a pedal powered generator, but at a power of 200 W, a typical healthy human will reach complete exhaustion and fail to produce any more power after approximately 1.3 hours. Portable radio receivers with a crank are made to reduce battery purchase requirements Self-powered equipment is a term used for electrical Today we also use the term Self powered equipment for electrical appliances which can be powered by human muscle power as an alternative to conventional sources of electricity such as primary batteries and the power grid, mechanically powered flashlights. Such devices contain electrical generators or an induction system to recharge their batteries. Separate crank-operated generators are now available to recharge battery-powered portable electronic devices such as cell phones. Others, such as mechanically powered flashlights, have the generator integrated within the device itself. A promising alternative to rechargeable batteries for electricity storage is super capacitors, now being used in some devices such as the mechanically powered flashlight shown here. Other devices store the energy mechanically, instead of in batteries. Clockwork radios have a mainspring which is wound up by a crank, and then turns a generator to power the radio.
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electrons in the windings to flow through the external electrical circuit. It is somewhat analogous to a water pump, which creates a flow of water but does not create the water inside. The source of mechanical energy may be a reciprocating or turbine steam engine, water falling through a turbine or waterwheel, an internal combustion engine, a wind turbine, a hand crank, compressed air or any other source of mechanical energy. The reverse conversion of electrical energy into mechanical energy is done by an electric motor, and motors and generators have many similarities. In fact many motors can be mechanically driven to generate electricity, and very frequently make acceptable generators.
Electric generator works on the principle of electromagnetic induction. It converts the mechanical energy available in to electric energy. When a coil is rotated in a magnetic field, then there will be induced current flowing in it. The direction of the induced current flowing in it can be found using Fleming’s Right Hand Rule.