Generator |
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| Process Description |
| The revolving movement of the turbine wheels is transmitted to the generator. The generator consists of a stator, a fixed part, and a rotor. As soon as the rotor moves within the stator an electrical voltage is generated in the coil windings of the stator. The basis for electricity generation with a generator is the electromagnetic induction, with the help of which the conversion of mechanical to electrical energy is possible. This phenomena which is described by M. Faraday becomes clear when a magnet is moved within a copper wire coil. The movement of the magnet in the coil induces an electrical voltage which is available at the coil ends. In a generator one simply rotates the magnet in front of coil packets.In practical application this generator principle is seen with internal pole machines and external pole machines. With internal pole generators, one taps the electrical energy from the fixed poles in the external area and lets one electromagnet rotate - a principle which is applied in most power plants. With external pole machines the coil turns within a fixed magnet. Like a bicycle dynamo which contains a permanent magnet, the movable magnets of the internal pole machines in power plants are electromagnets. The rotating electromagnet in the generator receives the dc current for the magnetic field from an additonal constant current generator sitting on the same axle and which is called the "exciter" machine. Every revolution of the magnet in the coil generates a sinus shaped alternating voltage at the coil ends . This sinus oscillation which is created by a full 360° revolution of the magnet is called a "period". In power plants alternating current generators are mostly used; these produc three alternating currents simultaneously. This alternating current is a three phase alternating current which is available at the generator terminals and which is passed on to the end user (industry, household, etc).over power lines. As of a certain size, the generators are cooled with nitrogen. Furthermore, extensive systems for the cooling and lubricating circuits of the bearings are required. |
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