三相异步电动机效率检测中绕组温度测量方法研究

1、三相异步电动机效率检测中绕组温度测量方法研究中文摘要 随着全球工业化进程的不断加快，对电机的需求也在不断增长。电机产品作为通用工业设备，每年消耗我国60%的电力能源，据财政部权威数据表明：我国电机耗电量约为2万亿千瓦时，占全国用电总量的60%和工业用电量的80%，电机节能无疑对我国节能减排目标的实现有着至关重要的作用。因而2012年5月11日国家质量监督检验检疫总局和中国国家标准化管理委员会联合发布了全新的强制性国家能效标准GB 18613-2012中小型三相异步电机能效限定值及能效等级，并于2012年9月1日起强制实施，此标准对中小型三相异步电动机的能效等级、能效限定值、目标能效限定值、节能评价值和试验方法作出了规定。GB18613-2012，是在GB 18613-2006基础上进行修订，为了让国内电动机效率水平满足国际标准内容要求，此外借鉴了国际标准IEC 60034-30单速三相笼型感应电动机效率分级，清楚指出电动机效率需要依照GB/T 1032 内的B法计算输入输出功率的损耗分析法开展计算。GB/T 1032-2012 标准要求B法计算效率时，在开展负载测试、空载测试时需要共同

2、测试所有负载试验点、所有电压试验点的绕组温度或绕组电阻R；此外，指出定子、转子铜损耗应换算到规定温度下的损耗。规定温度s是绕组工作温度w修正到冷却介质温度为25时的温度值。绕组工作温度w可按以下方法确定：（一）直接法进行额定负载热试验，热试验断电停机后，按外推法，作热电阻读数对断电后冷却时间的关系曲线外推至t=0时取得电阻值，从而确定绕组工作温度w；（二）由热电偶温度计直接测得绕组工作温度w。因此就可以知道，B法计算效率，测试的时候需要使用温度计法计算绕组温度或开展带电测绕组电阻。当前带电测试电阻仪器设施高昂，且故障频发，所以实验室使用B法效率测试的时候通常使用热电偶温度计法计算，因此就牵连到热电偶分布情况，此时标准GB/T 10322012中没有与之相关的内容。电动机运行产生损耗，损耗又以热能的形式散失，进而形成温度场；由于与散热条件有关，温度场内各个位置的热量分布状况出现差异，电机内部绕组各点的温度也会略有不同。效率求解公式繁多而复杂，绕组温度值的不同会导致多个变量随之改变，所以绕组温度的测量，对最终效率的测试结果影响较大。本论文以2.2kW三相笼型异步电动机为例,通过有限元软件A

3、NSYS下的Workbench平台创建三相异步电动机稳态温度场模型，对其额定情况下的稳态温度场开展研究统计，得出定子绕组区域的温度分布情况，以便掌握设备日常运作时的温度场分布状况，进而明确B法效率测试时绕组温度测试方法（热电偶测量的布置方案），并探寻了绕组温度测量的等效方式:外推法,为完善优化三相异步电动机效率试验方法提供了一些经验和建议。关键词：三相异步电动机，效率，绕组温度，测量方法Research on winding temperature measuring method in the check of three-phase asynchronous motors efficiencyAbstractAs the global industrialization develops rapidly, the demand for motor is growing. Motor products as general industrial equipment consume 60% of the electric energy in China; according to th

4、e data of ministry of finance, it indicates that Chinas electric power consumption is about 2 trillion kWh, accounting for 60% of the total electricity and 80% of industrial electricity. Motor energy-saving certainly plays a vital role in the realization of energy conservation and emissions reduction in China. So, on May 11, 2012, State Administration for Quality Supervision and Inspection and Quarantine (AQSIQ) and Standardization Administration of China jointly released a new version of mandat

5、ory national standard GB 18613-2012 “small and medium three-phase asynchronous motors allowable value of energy efficiency and energy efficiency grade”, and in 2012, September 1, it was enforced; the standard makes the rules for small and medium three-phase asynchronous motors efficiency level, allowable value of energy efficiency, limit value of target energy efficiency, energy saving evaluation and test method.GB18613-2012 is based on the revision of GB 18613-2006, with the aim to make the mot

6、or efficiency level in China in line with international standards, and with reference to the international standard IEC 60034-30 single-speed three-phase cage induction motor efficiency classification, it clearly puts forward the motor efficiency should be according to B method of GB/T 1032 - loss analysis of input - output power for measuring. GB/T 1032-2012 standard regulates B method to measure efficiency; when the load test and non-load test are conducted, winding temperature or resistance R

7、 of each load point and each voltage point must be measured at the same time. In addition, the stator, rotor copper loss should be transformed to the loss under the specified temperature. Specified temperatures is the temperature value that winding temperaturew is revised to the cooling medium temperature, that is, 25 . Winding temperaturew can be determined according to the following methods: (a) the direct method is used for rated load thermal test; after thermal test is in power outage, accor

8、ding to the extrapolation method, the relationship curve of a thermal resistance readings on the cooling time after power off, with extrapolation when the t = 0, it obtains resistance value, so as to determine the winding temperaturew; (b) the winding temperaturew is directly measured by thermocouple to take the largest thermometer readings of any thermometer. Thus, B method to measure efficiency requires, upon test, it must use a thermometer to measure winding temperature or electrified winding

9、 resistance. The electric resistance measurement instruments are expensive and easy to fail, so when the lab takes B method for efficiency testing, it usually adopts thermocouple thermometer method to measure the winding temperature, which involvs the thermocouple placement, and the standard of GB/T 1032-2012 does not specify it.Motor produces loss in running, and the loss is lost in the form of heat energy, thus forming temperature field; influenced by cooling condition, the distribution of the heat generated by the temperature field in different position is different, and the temperature of winding each point inside the motor will be slightly different. Efficiency solution formula is various and complex. Winding temperature difference will lead to the change of multiple variables，so the measurement of the winding temperature has greater influence on the final efficiency test result.This paper takes 2.2 kW three-phase sq

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