Working principle and maintenance of synchronous generator (electric ball)

Generator sets generally use synchronous generators (also known as electric balls) to convert the rotating mechanical energy of diesel engines into electrical energy. Various electrical equipment must rely on the power it emits to work, so the working performance requirements of synchronous generators are very high.

Working principle of synchronous generator

Synchronous generator is manufactured based on the principle of electromagnetic induction. Modern alternators usually consist of two parts of coils; in order to improve the strength of the magnetic field, part of the coil is wound in the groove of the inner wall of a cylinder stacked with a metal sheet with good magnetic conductivity. This cylinder is fixed to the base and is called a stator. The coils in the stator can output induced electromotive force and induced current, so it is also called an armature. Another part of the coil of the generator is wound in the groove of a cylinder stacked with a strong magnetic permeability metal sheet in the stator cylinder, called a rotor. A shaft passes through the center of the rotor and tightens it together, and the two ends of the shaft form a bearing support with the base. A small and uniform gap is maintained between the rotor and the inner wall of the stator and can rotate flexibly. This is called a brushless synchronous generator with a rotating magnetic field structure.

During operation, the rotor coil is connected to DC current to form a DC constant magnetic field. Driven by the diesel engine, the rotor rotates rapidly, and the constant magnetic field also rotates. The coil of the stator is cut by the magnetic field and the magnetic force line to generate an induced electromotive force, and the generator emits electricity.

When the rotor and its constant magnetic field are driven by the diesel engine to rotate rapidly, a rotating magnetic field is formed in the small and uniform gap between the rotor and the stator, called the rotor magnetic field or the main magnetic field. During normal operation, the stator coil of the generator, that is, the armature, is connected to a load. The induced electromotive force generated by the magnetic field magnetic force line is cut through the load to form an induced current. This current flows through the stator coil and will also generate a magnetic field in the gap, called the stator magnetic field or armature magnetic field. In this way, the rotor magnetic field and the stator magnetic field appear in the small and uniform gap between the rotor and the stator. These two magnetic fields interact to form a synthetic magnetic field. A generator generates electricity by cutting the stator coil from a magnetic line that synthesizes a magnetic field. Since the stator magnetic field is caused by the rotor magnetic field, and there is always a synchronous relationship between them first and second and the same speed, this generator is called a synchronous generator. Synchronous generators have many advantages in both mechanical structure and electrical performance.

Synchronous generators are a key part of diesel generator sets. It is very necessary to establish a suitable working environment for diesel generator sets and do a good job in daily maintenance. In daily power generation equipment operation, how to carry out synchronous generator maintenance? As a professional diesel generator set manufacturer, Haixing Power has made a basic summary and the following points must be done well in the maintenance of synchronous generators.

High temperatures, humidity and air pollutants in generator rooms are common factors that cause generator failure. The accumulation of dust, dust and other air pollutants will cause the performance of the insulating layer to deteriorate, which will not only easily form conductive paths to the ground, but will also increase the friction force of the rotor bearing part and generate heat. Moisture and moisture in air pollutants are very likely to form leakage paths to the ground in the generator, causing generator failure. Too high temperature in the machine room will make it difficult for the heat generated during the generator set to be dissipated, causing its output power to drop and the unit to overheat. Therefore, the dustproof, moisture protection, ventilation and cooling of the computer room are paid enough attention.

Whether it is a single-bearing generator or a dual-bearing generator, the coaxiality of their rotor shaft and the diesel engine spindle is very demanding. After a long period of operation, the coaxiality of the unit may sometimes decrease, resulting in an increase in the dryness of the generator and excessive temperature. It should be inspected and maintained regularly to maintain good coaxiality.

The load exceeds the rated load range of the generator, or the three-phase load is very unbalanced, which can also cause the generator efficiency to be reduced and overheated.