發電機的基本知識

來自專欄小小機械工程師的自我學習

發電機是將機械能轉換為電能。 在這裡我們只討論交流發電機。

基本知識：

當線圈相對於磁場運動時，就會有電勢產生

當導體切割磁力線時，就會產生電流

發電機的主要組成：

1） 轉子 Field(Rotor)

2） 定子 Armature(Stator)

3） 勵磁 Exciter

4） 電壓調節器 Automatic Voltage Regulator

發電機發電的過程

勵磁機提供直流電給轉子線圈， 在轉子線圈上產生磁場。當轉子旋轉時，磁場也跟著旋轉，切割定子的線圈，最終產生電壓，發電機輸出電壓。電壓調節器的作用就是監控發電機的輸出電壓值調整勵磁電壓確保發電機輸出的電壓為額定電壓

Essentially the process of generating voltage goes in the following order. The exciter provides DC current to the rotor windings. DC current through these wires creates magnetic flux. Magnetic flux generates an AC voltage in the nearby stator windings when there is relative motion between the two. The regulator then senses this output and controls the exciter current.

發電機主轉子的磁極（4極轉子）

轉速rpm，頻率f，極數poles之間的關係

發電機的輸出電壓取決於：

1） 轉子磁場與定子線圈的相對運動速度

2） 磁場強度

3） 定子上線圈匝數

Generator output voltage depends on the following:

· Speed of relative motion between magnetic field and stator conductors

· Strength of magnetic field

· Number of series turns in the stator windings

The strength of the magnetic field is proportional to the current flowing through the field coils.

The speed of relative motion between the magnetic field and the stator windings depends on the rotational speed of the rotor (engine rpm).

Voltage can be adjusted by arranging the stator windings in coils and varying the number of turns, or times the windings are wound around the stator. More voltage can be induced by increasing the number of turns and less voltage is induced by using fewer turns.

基本原理

防護等級Ingress Protection (IP)

This is protection both for persons in contact with moving parts and for the protection of machines against the harmful effects due to the collection of water and dust.

An IP designation is typically two digits, where the first digit is the level of protection from solid objects and the second digit is the level of protection from water.

IP23. The first digit, 2, indicates the machine is protected against solid objects

greater than 12 mm. The second digit, 3, indicates protection from spraying water.