@蛋白质吱吱声
视频：
电力公司使用“三相电力”发电和配电
电力公用事业使用“三相电力”产生和分配电力
To understand “three phase power”, we need to understand phasors.
要理解 “三相电源”, 我们需要理解相量。
Phasor diagrams can be used to describe all AC voltages and AC currents.
相图可用于描述所有交流电压和交流电流。
“Three phase power” consists of three AC voltages that are connected together.
“三相电源” 由三个交流电压连接在一起
At each moment in time,
在每个时刻
each of the voltages is described by the real component of its vector in the phasor diagram.
每个电压都是由其矢量在相量图中的真实分量来描述的。
This creates three sine waves that are offset from each other by 120 degrees.
这将产生三个正弦波, 彼此偏移120度。
Let’s call these “Phase A”…
让我们把这些叫做 “A相”..。
“Phase B”…
B相
And “Phase C.”
C相
We can think of each phase as an AC voltage source and a light bulb.
我们可以把每个相看作是一个交流电压源和一个灯泡。
Each light bulb represents several homes.
每个灯泡代表一个家庭用电。
The phasor diagram describes the voltage of each of the three wires.
相量图描述了三条导线的电压。
Phasor diagrams can also describe the current through each of the three wires.
相图还可以描述通过三条导线中的每一个线的电流。
The sum of the three currents is represented by the sum of the three vectors.
三个电流的总和由三个向量的总和表示。
If the three light bulbs are identical, the sum of the three currents is always zero.
如果三个灯泡是相同的, 三个电流的总和始终为零。
Since the sum of the three currents is always zero,
由于三个电流的总和始终为零,
we can remove the wires in the middle, and this will have no effect.
我们可以把中间的电线拆掉, 这样不会有任何影响。
This allows us to deliver electric power using fewer wires.
这使我们能够使用更少的电线提供电力
Another advantage of three phase power is that it is much easier for electric generators
三相电源的另一个优点是, 发电机更容易产生稳定的
to produce electricity if a steady constant output of power is required.
恒定输出功率的三相电源
Although the power through each light bulb is constantly fluctuating,
虽然通过每个灯泡的功率不断波动
the sum of the total power through all three light bulbs is always constant.
通过所有三个灯泡的总功率之和始终是恒定的。
The total power will also be constant
如果不在每一根导线与中性之间连接灯泡
if instead of connecting each light bulb between a line and the neutral,
总功率也将是恒定的
In this example, the light bulbs are now connected line to line,
在本例中, 灯泡现在已连接到线路,
but the three coils of the electric generator are still connected line to neutral.
但发电机的三个线圈仍然连接到中性线。
The voltages across the light bulbs are now larger than before,
灯泡上的电压现在比以前大了
because the “line to line” voltages are larger than the “line to neutral” voltages.
因为 “相与相” 电压大于 “相到中性线” 电压。
The “line to neutral” voltages are represented by the three small vectors,
“相到中性线” 电压由三个小矢量表示,
and the “line to line” voltages are represented by the three large vectors.
而 “相与相” 电压由三个大矢量表示。
The “line to line” voltages are offset from the “line to neutral” voltages by 30 degrees.
“相与相” 电压从 “线到中性线” 电压偏移30度。
Here, the “line to line” voltage waveforms are shown,
在这里, 显示了 “相与相” 电压波形,
which are larger than the “line to neutral” voltage waveforms by a factor of the square root of 3.
它等于 “相到中性线” 电压波形的根号3倍。
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