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
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[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
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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
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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。

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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
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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。

经过发展和更新，如今电动机保护器一般由电流检测电路、温度检测电路、基准电压电路、逻辑处理电路、时序处理电路、启动封锁及复位电路、故障记录电路、驱动电路、电动机控制电路组成。

电动机保护器的构成原理如图l所示。

By analyzing the motor protector the protection principle of it can be seen that the ideal motor protector should satisfy elements as reliable, economic, convenient, has high cost performance. Through the development and renewal, motor protector now generally by the current detection circuit, temperature detection circuit, voltage reference circuit, logic circuit, timing circuit, start the blockade and reset circuit, fault recording circuit, drive circuit, motor control circuit. The composition of motor protector principle as shown in figure l.
图1 电动机保护器组成模块和构成原理图
Figure 1 motor protector and composition principle graph modules 三、电动机保护器的类型及应用分析
Three, types and application analysis of motor protector
目前我国普遍采用的电动机保护器主要有热继电器、温度继电器和电
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子式电动机保护器。

热继电器是五十年代初引进苏联技术开发的金属片机械式电动机过载保护器，它在保护电动机过载方面具有反时限性能和结构简单的特点[2]。

但存在功能少，无断相保护，对电机发生通风不畅，扫膛、堵转、长期过载，频繁启动等故障不起保护作用。

这主要是因为热继电器动作曲线和电动机实际保护曲线不一致，失去了保护作用。

且重复性能差，大电流过载或短路故障后不能再次使用，调整误差大、易受环境温度的影响误动或拒动，功耗大、耗材多、性能指标落后等缺陷。

温度继电器是采用双金属片制成的盘式或其他形式的继电器，在电动机中埋入热元件，根据电动机的温度进行保护，但电动机容量较大时，需与电流监测型配合使用，避免电动机堵转时温度急剧上升，由于测温元件的滞后性，导致电动机绕组受损。

温度继电器具有结构简单、动作可靠，保护范围广泛等优点，但动作缓慢，返回时间长，3KW以上的三角形接法电动机不宜使用。

目前在电风扇、电冰箱、空调压缩机等方面大量使用。

电子式电动机保护器通过检测三相电流值和整定电流值，采用电位器旋钮或拔码开关操作来实现对电动机的保护，电路一般采用模拟式，采用反时限或定时限工作特性。

At present, the widely used main motor protector of thermal relay, temperature relay and electronic motor protector. Thermal relay is the early 50 s the introduction of the technology development of metal mechanical motor overload protector, motor overload protection in it has the characteristics of inverse time performance
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and simple structure [2]. But there is function less, no phase failure protection, ventilation for motor happened, he bore, locked-rotor, long-term overload, frequent start, etc. Can't fault protection. Mainly because the thermal relay operation curve and actual motor protection, lost the protection. And repeat performance is poor, cannot be used again after the big electric current overload or short circuit fault, the great error in the adjustment, easy misoperation or refuse to move under the influence of environmental temperature, large power consumption and a lot of consumables, backward performance indicators such as defects. Temperature relay is with double disc made of metal or other forms of relay, embedded in the motor components, according to the temperature of the motor, the motor capacity is bigger, the need to type and current monitoring, avoid stalling a motor temperature rise sharply, because of the lag of temperature measuring element, lead to motor winding is damaged. Temperature relay has the advantages of simple structure, reliable action, protect the advantages of wide range, but moves slowly, return time is long, unfavorable use delta connection of more than 3 kw motor. At present in electric fans, refrigerators, air-conditioning compressor, etc. Electronic motor protector by detecting three-phase current value and setting current value, or pull code switch operation using potentiometer knob to implement
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protection for motor, generally USES the analog circuit, adopt inverse time or definite time characteristic.
除了上述三种常见的电动机保护器，磁场温度检测型继电器和智能型电动机保护器也在电动机故障保护中得到普遍应用。

磁场温度检测型保护器通过在电动机中埋入磁场检测线圈和温度探头，根据电动机内部旋转磁场的变化和温度的变化进行保护，主要功能包括过载、堵转、缺相、过热保护和磨损监测，保护功能完善，缺点是需在电动机内部安装磁场检测线圈和温度传感器。

智能型电动机保护器能实现电动机智能化综合保护，集保护、测量、通讯、显示为一体。

整定电流采用数字设定，通过操作面板按钮来操作，用户可以根据自己实际使用要求和保护情况在现场自行对各种参数修正设定，采用数码管作为显示窗口，或采用大屏幕液晶显示，能支持多种通讯协议，目前高压电动机保护均采用智能型
In addition to the above three common motor protector, the field temperature detector relay and the intelligent motor protector is widely applied in the motor fault protection. Magnetic field temperature detection type protector by embedment magnetic field in motor coil and temperature probe, according to the change of inside the motor rotating magnetic field and temperature changes, main functions include overload, locked-rotor, lack of phase, overheating protection and wear monitoring, protection function, defect is need to install inside the motor magnetic field detecting
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coil and temperature sensor. Intelligent motor protector can realize intelligent motor protection, protection, measurement, communication and display. Adopting digital set setting current, operation by operation panel button, users can according to your actual use requirement and protect the situation at the scene to fixed setting of various parameters, using digital tube as a display window, or use large screen liquid crystal display, can support various communication protocol, the high voltage motor intelligent protection are adopted
四、电动机保护器应用选择原则
Fourth, motor protector application selection principles
选用电动机保护装置的目的，既能使电动机充分发挥过载能力，又能免于损坏，而且还能提高电力拖动系统的可靠性和生产的连续性。

合理选用电机保护装置，既能充分发挥电机的过载能力，又能免于损坏，从而提高电力拖动系统的可靠性和生产的连续性。

具体的功能选择应综合考虑电机的本身的价值、负载类型、使用环境、电机主体设备的重要程度、电机退出运行是否对生产系统造成严重影响等因素，力争做到经济合理。

在能满足保护要求的情况下首先考虑最简单保护装置，当简单的保护装置不能满足要求时，或对保护功能和特性提出更高要求时，才考虑应用复杂的保护装置，做到经济性和可靠性的统一。

Choose the purpose of the motor protection device, can make motor overload ability into full play, and free from damage, but also
can improve the reliability of electric power drag system and the continuity of production. Reasonable choice motor protection device, can give full play to the motor of the overload capacity, and free from damage, so as to improve the reliability of electric dragging system and the continuity of production. Specific function to select the motor be taken into account the value of itself, the types of load, the use of the importance of the environment, the main equipment in motor, electrical run out whether severe effects on the production system, strive to achieve the economic and reasonable. Are able to meet the protection requirements first consider the simplest protection device, when simple protection device can not meet the requirements, or to protect the function and properties put forward higher request, only consider applications complex protection, achieve the unity of the economy and reliability.
五、结束语
Five, the conclusion
如今电动机保护器已发展到了微电子智能型时代，电动机保护器也朝着多元化方向发展。

这就需要我们的工作人员在选型时应充分考虑电动机保护实际需求，超前、准确、及时地判断电动机的故障，合理选择保护功能和保护方式，实现对电动机的良好保护，达到提高设备运行可靠性，减少非计划停车，减少事故损失的目的。

Motor protector now has developed into microelectronics era, intelligent motor protector and development in the direction of diversification. This needs our staff in the selection of motor protection should be considered when the actual demand, advanced, accurate, and timely judge the failure of the motor, choose the protection function and the way of protection, for the good protection of the motor, to improve equipment reliability and reduce the unscheduled stop, the purpose of reducing accident loss.。