什么是涡流测力计:施工及其工作

An eddy current测力计与传统的机械测功机相比,是一种特殊的损耗,高效率和更通用的装置。在涡流测功机中,由于绕组和激发之间没有任何物理接触,损失较少。由于其小尺寸和可巧妙,它具有许多应用,甚至对于测试内燃机的性能,即将用作负载。本文讨论了涡流测功机的概述。

什么是涡流测力计?

An eddy current dynamometer is an electromechanical energy conversion device, which converts mechanical energy to electrical energy. It fundamentally uses Faraday’s Law of电磁感应作为其工作原则。测力计的示意图如下所示。


施工
施工

The constructional aspects of the eddy current dynamometer are shown in the above figure. It consists of the outer frame as the stator, which is also called a stationary member of the machine. The stator consists of windings, which are placed in stator slots. When the stator windings are excited, a stator magnetic field is produced in the stator coils. In the case of high rated machines, 3 phase windings are placed in the stator slots.

定子绕组由铜制成。外框架,即定子由铸铁或硅钢等磁性材料制成,在精细的应用的情况下。旋转构件被称为转子,转子保持在定子线圈下方。转子放置在轴上,使其可以旋转。转子绕组放置在转子槽上。在重型机器的情况下,三相转子绕组用于保持在转子槽上。

The rotor must be connected to the prime mover, such that when the prime mover rotates, it provides the mechanical input to the device. A D.C supply is used to excite the stator windings. In the case of large machines,整流器单位用于实现此直流电源。对于大型机器,油用于冷却和绝缘定子绕组。这对于消散产生的热量是重要的。

Once current meter as shown in the diagram is used to measure the current produced and torque induced. A pointer is connected by an arm to the stator, which can measure the torque generated in the rotor. And with the knowledge of speed, by using this torque value, we can calculate the power generated in the machine.


Dynamometer Working

涡流测功机采用法拉德电磁诱导法原理。根据法律,每当一组导体和磁场之间存在相对位移时,在导体的集合上诱导EMF。调用该EMF是动态诱导的EMF。在测功机的情况下,当定子杆用连接到定子的直流电源激发时。

加工
加工

When the DC supply is connected, the stator coils are excited and a magnetic field is produced in the stator coils. In the case of a three-phase machine, we obtain a 3 phase rotating magnetic field, in the stator coils when the coils are excited with the three-phase supply. When the prime mover rotates, the rotor, the rotor coils rotate and interact with the stator magnetic field.

必须注意的是,在此,定子磁场本质上是静态的。由于激励是DC,我们得到一个静态磁场。当转子线圈切割定子磁场时,诱导EMF,因为在这种情况下,磁场是静态的,导体旋转。因此,磁场和导体之间存在相对位移。

Features of Eddy Current Dynamometer

It must be observed that the eddy current dynamometer is different from than conventional机械测功机。在这种情况下,当测功机的转子切割定子磁场时,在转子导体上感应EMF。它导致涡流在转子导体中流动。涡流的方向与磁通量的变化相反,并在转子中产生。

转子与磁通量施加的力相反,但由于原动机输入,它保持旋转。并且由于磁场和导体之间没有物理接触,所产生的损耗非常少于与传统发电机的比较。

与传统的机械测功机不同,在涡流测功机中,臂连接到定子的主体。在臂的末端,连接指针,可以测量转子绕组中产生的扭矩。通过了解转子的速度,可以知道功率的量,因为功率等于扭矩和速度的乘积。

测功机的优点

涡流测功机的优点是

  1. 由于低摩擦损失,与传统的机械测功机相比,更有效。
  2. Its structure is simple
  3. 与传统测量仪相比,它可以更方便地操作
  4. It has a fast dynamic response because of low rotational inertia.
  5. Due to the absence of huge windings, the number of copper losses is less.
  6. 它可以容易地连接到外部控制单元,以监视电流的流动甚至控制它。
  7. The braking torque is very high
  8. 它高度精确和稳定

Applications

The major applications are

  • Performance testing of the internal combustion engine
  • Used in small power motor
  • Automobile transmission parts
  • Gas turbines
  • Water turbines

Hence we have seen the working principles of dynamometers that are compact and versatile in nature. It must be thought, how one can bring the operating characteristics of an eddy current测力计up to the level of conventional mechanical dynamometers?

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