电气专业英语课后练习翻译

PART1

U1T1、

In addition to the various power transformers, two special-purpose transformers are

used with electric machinery and power systems. The first of these special

transformers is a device specially designed to sample a high voltage and produce a

low secondary voltage directly proportional to it. Such a transformer is a potential

transformer. A power transformer also produces a secondary voltage directly

proportional to that the potential transformer is designed to handle only a very small

current. The second type of special transformer is a device designed to provide a

secondary current much smaller than but directly proportional to its primary current.

This device is called a current transformer.

除了各种电源变压器、两个专用变压器使用电动机械和电力系统。第一个特殊变压器是一个高电压设备专门设计的样品和生产较低的二次电压成正比。这样一个变压器电压互感器。电力变压器也产生二次电压成正比的电压互感器的设计目的是处理只有一个很小的电流。第二种类型的特殊变压器是一个装置,旨在提供一个次级电流小得多,但它的主要电流直接成比例。这种装置称为电流互感器。

U1T2、

In electronic power supplies there is often a need to isolate the output from the input

and reduce the weight and cost of the unit. In other applications, such as in aircraft,

there is a strong incentive to minimize weight. These objectives are best achieved by

using a relatively high frequency transformer. Thus, in aircraft the frequency of

transformers is typically 400Hz, while in electronic power supplies the frequency of

transformers may range from 5kHz to 50kHz.

在电子电源通常需要隔离的输出输入,减少单位的重量和成本。在其他应用程序,如飞机,有强烈的动机来减少体重。这些目标是最好通过使用一个相对高频变压器。因此,在飞机变压器通常是400赫兹的频率,而在电子电源变压器可能范围从5 khz的频率50千赫

U2T1、In general, the outstanding advantage of DC machines lies in their flexibility

and versatility. Before the widespreaded availability of AC motor drives, DC

machines were essentially the only choice available for many applications requiring a

high degree of control. Their principal disadvantages stem from the complexity

associated complexity increase the cost over competing AC machines, it also

increases the need for maintenance and reduces the potential reliability of these

machines.

一般来说,直流机的突出优势在于他们的灵活性和通用性。交流电动机驱动的广泛可用性之前,直流机基本上是唯一可用的选择对于许多应用程序要求高度的控制。主要缺点源于复杂关联的复杂性增加了成本在竞争交流的机器,它也增加了对维护的需要,减少了潜在的这些机器的可靠性。

U2T2、

There are three basic type of rotating machines: synchronous, induction, and DC

machines. In all of them the basic principles are essentially the same. Voltages are

generated by the relative motion of a magnetic field with respect to a winding, and

torques are produced by the interaction of the magnetic fields of the stator and rotor

windings.

有三种基本类型的旋转机器:同步,感应,直流机器。在所有这些基本原则基本上是相同的。电压的相对运动产生的磁场对绕组,和扭矩的交互作用是由定子和转子绕组的磁场。

U3T1、

Synchronous machines can be classified as cylindrical-rotor or salient-pole machines.

The cylindrical-rotor construction is used in high-speed steam-turbine-driven

generators. The armature windings consist of laminated conductors placed in the

stator slots. The rotor carries the DC field winding. Most of turbine generators being

built at present for 60 Hz service are 2-pole 3600 revolutions per minute machines.

Because of the economies of high-speed high-temperature high-pressure steam

turbines, much study and some real pioneering work have been devoted to

improvements in materials and design of both generators and turbines

同步机可分为圆柱形转子或凸极机。圆柱形转子建设用于高速steam-turbine-driven发电机。电枢绕组由叠层导体放置在定子槽。转子直流磁场绕组。目前大部分涡轮发电机建60赫兹服务2-pole每分钟3600转的机器。因为经济的高速高温高压蒸汽涡轮机,多学习和一些真正的开创性工作一直在致力于改进材料和设计的发电机和发电机

U3T2、

Rotating electric machines take many forms and are known by many names: DC,

synchronous, permanent-magnet, induction, etc. Although these machines appear to

be quite dissimilar and require a variety of analytical techniques, the physical

principles governing their behavior are quite similar, and in fact these machines can

often be explained from the same physical picture. An induction machine, in spite of

many fundamental differences, works on exactly the same principle; one can identify

flux distributions associated with the rotor and stator, which rotate in synchronism and

which are separated by some torque-producing angular displacement.

旋转电机采取多种形式和已知许多名字:直流、同步、永磁、感应,等等。虽然这些机器似乎是相当不同的,需要各种分析技术,管理他们的行为非常相似的物理原则,事实上这些机器通常可以解释从相同的物理图像。感应式电机,尽管许多根本性的差异,同样的原理工作;一个可以识别通量分布与转子和定子,在同步旋转,由一些torque-producing角位移

U4T1、

The significance of VRMs in engineering applications stems from their low cost,

reliability, adn controllability. Because their torque depends only on the square off

applied stator currents and not on their direction, these machines can be operated from

unidirectional drive systems, reducing the cost of the power electronics. However, it is

only recently, with the advent of low-cost, flexible power electronic circuitry and

microprocessor-based control systems, VRMs have begun to see widespread