变压器 TRANSFORMER

译文：变压器 TRANSFORMER(中文7700字,英文4900字)
变压器的大小不一。有的变压器象房子一样大。而电子变压器可能小如糖块。所有的变压器至少有一只线圈；大多数变压器具有两个或两个以上的线圈。
通常使用变压器的目的是改变电压等级，但有时也用于隔离电源和负荷。
变压器的类型：
标准电力变压器有两只线圈。这些线圈标记为一次绕组（一次侧）和二次绕组（二次侧）。一次绕组连接电源，二次绕组连接负荷。在一次和二次绕组间没有电的连接。二次绕组通过电感应获得电压。
大概只有在发电厂才能见到升压变压器。典型的发电机出口电压为13800V，升压至345000V用来输送。下一站是变电所，把电压降到配电电压等级，约为15000V。大型的变电所变压器具有冷却叶片，以防止变压器过热。有的变压器安装的位置靠近用户。

原文：TRANSFORMER
Transformers come in many sizes. Some power transformers are as big as a house. Electronic transformers, on the other hand, can be as small as a cube of sugar. All transformers have at least one coil. Most have two although they may have many more.
The usual purpose of transformers is to change the level of voltage. But sometimes they are used to isolate a load from the power source.
TYPES OF TRANSFORMERS
Standard power transformers have two coils. These coils are labeled PRIMARY and SECONDARY. The primary coil is the one connected to the source. The secondary is the one connected to the load. There is to no electrical connection between the primary and secondary. The secondary gets its voltage by induction.
The only place where you will see a STEP-UP transformer is at the generating station. Typically, electricity is generated at 13,800 volts. It is stepped down to distribution levels, around 15,000 volts. Large substation transformers have cooling fins to keep them from overheating. Other transformers are located near points where the electric power is used.