Generators are widely used in industrial and agricultural production, national defense, science and technology and daily life. Generators come in many forms, but they all work on the basis of the laws of electromagnetic induction and electromagnetic force. Next, let’s understand the main characteristics of the motor.
1. Working characteristics
The performance of synchronous generators is mainly characterized by no-load characteristics and load operation characteristics. These characteristics are important basis for users to choose generators.
2.No load characteristics
When the generator is not connected with load, the armature current is zero, which is called no-load operation. At this time, the three-phase winding of the motor stator only has the no-load electromotive force E0 (three-phase symmetry) induced by the excitation current If, and its size increases with the increase of If. However, because the motor magnetic circuit core saturation phenomenon, so the two are not proportional. The curve reflecting the relation between the no-load electromotive force E0 and the excitation current If is called the no-load characteristic of synchronous generator.
3. Armature reaction
When the generator IS CONNECTED to a symmetrical load, THE three-phase current IN the ARMATURE winding generates another rotating magnetic field, called the ARmature reactive field. Its speed is exactly equal to the speed of the rotor, and the two rotate synchronously.
The armature reactive magnetic field and the rotor excitation magnetic field of the synchronous generator can be approximated to be distributed according to the sinusoidal law. The spatial phase difference between them depends on the time phase difference between the no-load electromotive force E0 and the armature current I. The armature reaction magnetic field also depends on the load condition. When the load of the generator is inductive, the armature reaction magnetic field plays the role of demagnetization, which will reduce the voltage of the generator. When the load is capacitive, the armature reaction magnetic field plays the role of magnetic aid, which will increase the output voltage of the generator.
4. Load operation characteristics
Mainly refers to the external characteristics and adjustment characteristics. The external characteristic is the relationship between the generator terminal voltage U and the load current I when the speed is rated, the excitation current and the load power factor are constant. The adjusting characteristic is the relationship between the excitation current If and the load current I when the speed and terminal voltage are rated and the load power factor is constant.
The voltage change rate of synchronous generator is about 20 ~ 40%. General industrial and domestic loads require the voltage to remain basically constant. Therefore, with the increase of load current, the excitation current must be adjusted accordingly. Although the TREND OF THE ADJUSTMENT CHARACTERISTIC IS OPPOSITE TO THAT OF the external characteristic, it INCREASES for inductive and purely resistive loads and generally decreases for capacitive loads.
If the speed, governor flight block of the centrifugal force is too large, this will overcome the speed control spring tension and pull rod oil tooth rod in the direction of oil reduction. And the supply rod is equivalent to the position of the low speed supply rod, if the idle oil supply adjustment is not uniform. The error is too large, which will inevitably affect the stability of the large load without load. When the engine reaches the speed of stopping oil, the fuel pump should automatically cut off the oil. If the quality of the plunger or oil valve connector is not uniform, or the oil fracture is inconsistent due to different wear. It may not supply oil to some cylinders, and some cylinders still have a small supply of oil or oil cut. This will be high-speed unstable, diesel generator rental] generator set voltage abnormal troubleshooting method. Motor control panel voltage adjustment does not work or the range is not enough, there may be two such errors.
Jiangsu Meiao Power Technology Co., Ltd. is an important manufacturer of diesel generators. The company mainly manufactures and sells diesel generator sets with power of 3-3000kW, mobile power station of 24-600kW, Marine emergency diesel generator set of 24-800kW, gas generator set, heavy oil generator set and all kinds of imported series, special series (trailer, static speaker, mobile lighthouse, container, etc.) diesel generator At the same time, we are engaged in generator set maintenance and after-sale service of generator set accessories.
