工作特性：　　表征同步發(fā)電機性能的主要是空載特性和負載運行特性。這些特性是用戶選用發(fā)電機的重要依據(jù)。

　　Working characteristics: The main characteristics that characterize the performance of a synchronous generator are no-load characteristics and load operating characteristics. These characteristics are important criteria for users to choose generators.

　　01空載特性發(fā)電機不接負載時，電樞電流為零，稱為空載運行。此時電機定子的三相繞組只有勵磁電流If感生出的空載電動勢E0（三相對稱），其大小隨If的增大而增加。但是，由于電機磁路鐵心有飽和現(xiàn)象，所以兩者不成正比。反映空載電動勢E0與勵磁電流If關系的曲線稱為同步發(fā)電機的空載特性。

　　When the generator is not connected to a 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 magnitude increases with the increase of If. However, due to the saturation phenomenon of the iron core in the motor magnetic circuit, the two are not proportional. The curve reflecting the relationship between the no-load electromotive force E0 and the excitation current If is called the no-load characteristic of a synchronous generator.

　　02電樞反應當發(fā)電機接上對稱負載后，電樞繞組中的三相電流會產(chǎn)生另一個旋轉磁場，稱電樞反應磁場。其轉速正好與轉子的轉速相等，兩者同步旋轉。同步發(fā)電機的電樞反應磁場與轉子勵磁磁場均可近似地認為都按正弦規(guī)律分布。它們之間的空間相位差取決于空載電動勢E0與電樞電流I之間的時間相位差。電樞反應磁場還與負載情況有關。當發(fā)電機的負載為電感性時，電樞反應磁場起去磁作用，會導致發(fā)電機的電壓降低；當負載呈電容性時，電樞反應磁場起助磁作用，會使發(fā)電機的輸出電壓升高。

　　When the generator is connected to a symmetrical load, the three-phase currents in the armature winding will generate another rotating magnetic field, called the armature reaction magnetic field. Its rotational speed is exactly equal to the rotational speed of the rotor, and both rotate synchronously. The armature reaction magnetic field and rotor excitation magnetic field of a synchronous generator can be approximately assumed to be distributed in a sinusoidal pattern. 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 is also related to the load condition. When the load of the generator is inductive, the armature reaction magnetic field has a demagnetization effect, which can cause a decrease in the voltage of the generator; When the load is capacitive, the armature reaction magnetic field plays a magnetic assisting role, which will increase the output voltage of the generator.

　　03負載運行特性主要指外特性和調整特性。外特性是當轉速為額定值、勵磁電流和負載功率因數(shù)為常數(shù)時，發(fā)電機端電壓U與負載電流I之間的關系。調整特性是轉速和端電壓為額定值、負載功率因數(shù)為常數(shù)時，勵磁電流If與負載電流I之間的關系。同步發(fā)電機的電壓變化率約為20～40%。一般工業(yè)和家用負載都要求電壓保持基本不變。為此，隨著負載電流的增大，需要相應地調整勵磁電流。雖然調整特性的變化趨勢與外特性正好相反，對于感性和純電阻性負載，它是上升的，而在容性負載下，一般是下降的。

　　03 Load operation characteristics mainly refer to 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 adjustment 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 generators is about 20-40%. Both industrial and household loads generally require voltage to remain relatively constant. Therefore, as the load current increases, it is necessary to adjust the excitation current accordingly. Although the trend of adjusting characteristics is exactly opposite to that of external characteristics, for inductive and purely resistive loads, it increases, while under capacitive loads, it generally decreases.

　　本文由 合金尾氣發(fā)電機組   友情奉獻.更多有關的知識請點擊  http://shgcmy.com/   真誠的態(tài)度.為您提供為全面的服務.更多有關的知識我們將會陸續(xù)向大家奉獻.敬請期待.

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