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Synchronous motor efficiency test method

Time:2020-04-15 02:04Source:Tension

  For the efficiency test of motors, the measurement methods adopted by different motors are different. Today, let's take a look at the methods of efficiency testing of synchronous motors and how to test them.

  Synchronous motors, like induction motors, are a commonly used AC motor. The efficiency measurement of the synchronous motor is very important. Only by accurately measuring the efficiency of the motor and understanding the performance characteristic curve of the motor can we find an effective method to improve the efficiency of the synchronous motor.

  Synchronous motor is a commonly used induction AC motor. Its efficiency measurement includes direct measurement method, indirect measurement method, calorimetry method and self-deceleration test method. The most commonly used methods are direct measurement method and indirect measurement method.

  Direct measurement method for synchronous motor efficiency measurement

  1 Braking method

  When the tested motor is operating as a motor, it is connected with a brake or a dynamometer, and the brake or dynamometer is used to measure the torque of the tested motor, and at the same time, the speed is measured to determine the output power of the motor. The input power is a power analyzer or other Electrical instrument measurement.

  当被试电机作发电机运行时,用测功机拖动被试机,并用测功机测量被试电机的输入功率,用功率分析仪或者其他电气仪表测量。

  由于电机转速直接影响功率的计算,因此转速的测量要求非常精确。

  2校准电机法

  被试电机与校准过的电机机械耦合,用校准电机测量被试电机的输入或输出功率,用功率分析仪或者其他电气仪表测量被试电机的输入或输出功率。

  3对拖法

  把两台相同的电机机械耦合,一台作电动机运行,另一台作发电机运行。用功率分析仪或者其他电气仪表测量电动机的输入功率和发电机的输出功率,当两台电机的运行工况基本相同时,可假设损耗是平均分担的,则电动机的输出功率为输入功率与总损耗一半的差,而发电机的输入功率与总损耗一半的和。

  同步电机效率测量间接测量法

  同步电机效率测量间接测量法对试验测量设备提出了较高的要求。间接测量法就是损耗分析法,需要分别测定或计算同步电机的各项损耗,包括恒定损耗P0、负载损耗Pcue、励磁损耗Pf、杂散损耗Pd。

  同步电机效率测量量热法

  直接测量法和损耗分析法是最常见的同步电机效率测量方法,当两者均不能使用时,可以采用热量法来测量同步电机的效率。

  可以通过空载电动机法和空载发电机法来确定恒定损耗,再同步电机的空载特性曲线分离出机械耗和铁耗,可以额定电流运行下的电流测量值计算电枢绕组损耗、励磁损耗、电刷电损耗等。

  同步电机效率测量自减速试验

  自减速试验主要适用于转动惯量较大以及其他方法测定各项损耗有困难的电机。试验时被试电机接到频率可调的电源上,也可由其他动力机拖动并由独立的直流电源供电他励。先将被试电机加速,使其转速稍高于额定转速,然后切断电源,使电机自减速。量取从最高转速到设定转速(隐极机量为95%额定转速、凸极机量为90%额定转速)之间的时间,上下两个速度点之间的时间测量准确度要求达到2%以内。在自减速过程中量取电枢电流和励磁电流,然后根据测量得到的数据计算机械损耗,恒定损耗,负载损耗、杂散损耗等。