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e plate the compressor shaft will start to rotate at pulley speed. When this frictional contact occurs the compressor is commonly described as being engaged. When the supply of current to the stator is removed by the A/C clutch relay opening, a spring, seated against the pressure plate, pushes the pressure plate out of contact with the pulley and the pulley is again disengaged from driving the compressor and rotates freely.
这一磁场牵引承压板沿压缩机轴的齿槽运动。在压缩机轴上，承压板同轮子咬合。一旦轮子和承压板间存在摩擦接触，压缩机轴将开始以轮速转动。当摩擦接触发生时，压缩机被认为是被启用了。A/C离合继电器的开启会切断轮子的电流供应。此时，安装在承压板后的弹簧弹起，推动承压板使其与轮子分离，轮子再次脱离，不再驱动压缩机并开始自由转动。
      Compressor speed sensor 压缩机速度感应器
Some compressors are additionally fitted with a revolution speed sensor. This speed sensor value is monitored in relation to engine speed by the A/C amplifier (amplifier programming takes into account the pulley drive ratio). This comparison gives the A/C amplifier the ability to identify belt and/or magnetic clutch slippage, or even a locked up compressor. In this instance, to protect the system, the magnetic clutch is disengaged and A/C operation will cease. The driver is notified about this fault through the light on the A/C on/off button flashing or by some other means dependent upon manufacturer.
一些压缩机另外配有一个转速感应器。这一感应器值由A/C扩大器监控，并把它与引擎转速作对比。扩大器程序中会有一项参数为轮传动比。这一比较使A/C扩大器能够识别带子和、或电磁离合器的滑动量，甚至是一个锁定的压缩机。在本文的情况下，为保护系统，我们将切断电磁离合器，A/C也将停止运行。驾驶员可以根据A/C的开关灯的闪烁或者其他途径（取决于制造商）发现这一情况。
 

High pressure switch 高压开关
A pressure switch is fitted in the high-pressure side of the system. It can be placed in a selection of locations but it will always be found somewhere in the high pressure part of the circuit in between the compressor output and the thermal expansion valve. Two pressure sensitive switches (diaphragm operated) are located into the one unit. 在系统的高压侧装有一个压力开关。它可以被安装在几个位置上，但这些位置仅限于线路的高压侧，且在压缩机输出端和热力膨胀阀之间。两个隔板操控的压力感应开关被安装在一个元件中。
 The two switches combined are able to indicate three conditions. The first switch (switch 1), under normal operating pressures (typically 15 bar) will be in its closed or in its “on” state. If the pressure applied to it by the refrigerant is too high (26-30 bar), the switch contacts will open. Once the circuit is broken the amplifier detects the voltage change in this circuit and de-energises the magnetic clutch relay, turning the compressor off. This is done to prevent the system over-pressurising which could cause permanent damage to numerous components in the circuit. Conversely, if the pressure in the high pressure part of the circuit drops significantly (to 1–2 bar), the same switch opens in the other direction, again opening the contacts. This again leads to the same outcome of turning off the compressor. The most likely cause of such low pressure in the high pressure side of the system would be insufficient refrigerant. As the refrigerant is used as a ‘vehicle’ for the system’s lubricating oil, this could lead to seizure, hence the action of switching off the compressor. 两个开关共同作用，结果有三种情况。第一个开关，即开关1，在正常工作电压（15巴）下是闭合的或者状态为“on”（运行）。如果制冷剂对它施加压强太高（26-30巴），开关触点将本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。