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Main Characteristics Of Generators

Jul 06, 2017

            Operating characteristics: The performance of synchronous generators is characterized by no-load characteristics and load operating characteristics. These characteristics are the important basis for the user to choose Generators.

            No-load characteristics: When the generator is not connected to the load, the armature current is zero, called no-load operation. At this time, the three-phase winding of the motor stator is only the E0 (three relative) of the no-load electromotive force produced by the excitation current if sense, and its size increases with the increase of IF. However, because the magnetic circuit core of the motor saturation phenomenon, so the two are not proportional. The curve that reflects the E0 of no-load electromotive force and excitation current is called the no-load characteristic of synchronous generator.Generator

           Armature reaction: When the generator is connected with the symmetrical load, the three-phase current in the armature winding produces another rotating magnetic field, called the armature reaction magnetic field. Its rotational speed is exactly the same as that of the rotor, and the two rotate synchronously. The armature reaction magnetic field of synchronous generator and the excitation magnetic field of the rotor can be approximately distributed according to Sine law. The space difference between them depends on the time phase difference between the no-load EMF E0 and the armature current I. The armature reaction magnetic field is also related to the load condition. When the load of the generator is electrical sensibility, the armature reaction magnetic field plays a demagnetization role, which will cause the voltage of the generator to decrease; When the load is capacitive, the armature reaction magnetic field plays a role in helping to increase the output voltage of the generator.

           Load operating characteristics: mainly refers to external characteristics and adjustment characteristics. The external characteristic is the relationship between the voltage U and the load current I of the generator when the speed is the nominal value, the excitation current and the load power factor are constant. The adjustment characteristic is the relation between the speed and the end voltage as the rated value and the load power factor is constant, the excitation current if and the load current I. The voltage variation rate of synchronous generators is about $number. General industrial and household loads require that the voltage remain basically unchanged. Therefore, as the load current increases, the excitation current must be adjusted accordingly. Although the change trend of the adjustment characteristic is opposite to the outward characteristic, for the perceptual and the pure resistive load, it is ascending, but under the capacitive load, the general is descending.Generator