浅谈电动机保护器的保护原理及应用

浅谈电动机保护器的保护原理及应用摘要：电动机保护器作为拖动系统中的重要组成部分，对电动机的起动和运行中保护起着至关重要的作用。

本文分析了电动机保护器保护及构成原理，并阐述了电动机保护器在发展过程中的应用及选择原则。

Abstract: the motor protector as an important part of drag system, starting and running of motor protection plays an important role. Motor protector to protect and composition principle are analyzed in this paper, and expounds the motor protector the application and selection principles in the development process.关键词：电动机；保护器；保护原理；应用Key words: electric motor; The protector; Protection principle; application一、引言First, the introduction电动机是当前应用最广泛的动力设备，是其他机电设备的动力源泉，电动机正常的输出是其驱动的机电设备正常工作的前提，如今已被广泛应用于工农业、交通运输、国防等领域。

电动机所带的负载种类繁多，且往往是整个设备中的关键部分，因而确保电动机的正常运行就显得十分重要。

电动机保护器（电机保护器）是发电、供电、用电系统的重要器件，是跨行业、量大面广、节能效果显著的节能机电产品//[1]。

电动机保护器的作用是给电机全面的保护控制，在电机出现过流、欠流、断相、堵转、短路、过压、欠压、漏电、三相不平衡、过热、接地、轴承磨损、定转子偏心时、绕组老化予以报警或保护控制。

如今电动机保护器几乎渗透到所有用电领域，在国民经济和节能事业中有着不可替代的重要地位和作用。

Is currently the most widely used electric motor power equipment, is other mechanical and electrical equipment power source, the output of the motor is normal is the precondition of its driving mechanical and electrical equipment normal work, now has been widely used in industry and agriculture, transportation, national defense and other fields. Motor with the load range, and is often a key part of the entire device, thus ensure the normal running of electric motor becomes very important. Motor protector, motor protector) is one of the important device, power generation, power supply and utilization system, is a cross-industry, enormous quantity wide, energy-saving effect is remarkable energy-saving mechanical and electrical products [1]. Motor protector role is of comprehensive protection for motor control, the motor show flow, owe flow, phase failure, locked-rotor, short circuit, overvoltage, undervoltage, electric leakage, three-phase unbalance, overheating, grounding, bearing wear, or when the rotor eccentricity, winding aging give alarm or protection control. Motor protector now/ /permeates nearly all areas of electricity in the national economy and energy saving has irreplaceable important position and role. 二、电动机保护器的保护原理与构成Second, the protection principle and the composing of the motor protector对电动机来说，其故障形式从机械角度可以分为绕组损坏和轴承损坏两方面。

造成绕组损坏的主要原因有：1.电动机长时间的电、热、机械和化学作用下，绕组的绝缘老化损坏，定转子绕组匝间短路或是对地短路。

2.电网供电质量差，电源电压三相不平衡、电压波动大、电网电压波形畸变、高次谐波严重或者电动机断相运行。

3.电源电压过低使得电动机启动转矩不够，电动机不能顺利启动或者是在短时间内重复启动，电动机长时间承受过大的启动电流导致电机过热。

4.因机械故障或其它原因造成电动机转子堵转。

5.某些大型电机冷却系统故障或是长时间工作在高温高湿环境下造成电机故障。

For motor, the fault forms from the mechanical point of view can be divided into two aspects of winding damage and bearing damage. Winding damage of the main reasons are: 1. The electric machine long time under the action of electrical, thermal, mechanical and chemical, winding insulation aging damage of stator winding interturn short circuit or to ground short circuit. 2. Poor quality of power supply, three-phase voltage unbalance, voltage fluctuation, voltage waveform distortion, high order harmonic serious or motor//open phase running. 3. The power supply voltage is too low not enough starting torque of the motor, the motor does not start smoothly or is repeated in a short time start, electric machine long time under large starting current lead to motor overheating. 4. Because of mechanical failure or other causes motor rotor is blocked. 5. Some large motor cooling system failure or work long time under high temperature and high humidity environment cause motor failure.电动机保护原理的研究是保证电动机保护器性能高低的关键，根据三相对称分量法的理论，三个不对称的向量可以唯一分解成三组对称的向量，分别为正序分量、负序分量和零序分量。

对称分量的计算公式如下：Motor protection principle of the research is the key to guarantee the motor protector performance of high and low, according to the theory of three-phase symmetrical component method, three asymmetric vector symmetric vector can be resolved only into three groups, respectively for the positive sequence, negative sequence and zero sequence components. Symmetrical component computation formula is as follows:根据（1）式，电动机在发生对称故障和不对称故障时，电动机的三相电流都会发生变化。

电动机故障条件流过绕组的电流过大，超过电动机的额定电流，因此可根据这一特征来对电动机过电流进行保护。

/ /电机过载、断相、欠压都会造成绕组电流超过额定值。

电源电压欠压，运行电流上升的比例将等于电压下降的比例；电机过载时，常造成堵转，此时的运行电流会大大超过额定电流。

针对以上情况，电动机保护器可通过对三相运行电流进行检测，根据运行电流的不同性质来确定不同的保护方式，从而对电机予以的断电保护。

电动机的故障类型分为过流保护、负序电流保护、零序电流保护、电压保护和过热保护等几种。

According to (1), the motor in the case of symmetrical fault and asymmetric fault, the three phase current of the motor will change. Excessive current through the winding motor fault conditions, more than the rated current of the motor, so can according to the features of motor over-current protection. Motor overload, undervoltage, phase can create over winding current rating. Power supply voltage under-voltage, running current rise in proportion to the ratio will be equal to the voltage drop; Motor overload, often caused by blocked, running current at this time would be considerably more than the rated current. In view of the above situation, motor protector can run through the three-phase current for testing, according to the different nature of running current to determine the different ways of protection, the power of motor shall be protected. The malfunction of the motor types are classified as over-current protection, negative sequence current protection, zero sequence current//protection, voltage protection, overheating protection, etc.通过对电动机保护器的保护原理分析可以看出，理想的电动机保护器应满足可靠、经济、方便等要素，具有较高的性能价格比。