A brief discussion on the history of dynamometers and motor test systems

The origin of the motor test system

As we all know, motors are a fusion of electrical and mechanical elements. To evaluate the performance of a motor, it is often necessary to combine the results of many test projects. Generally, from R&D to production, a motor needs to go through two stages: type test (R&D, pilot test, quality inspection) and production test (factory). Depending on the type of motor and the application industry, there will be more than ten or even dozens of test projects in total (as shown in the figure below).

Since there are so many test items for motors, a lot of test instruments or equipment are needed to complete the test of each item. For example, the collection of voltage, current, and power requires the use of an electrical parameter tester; the collection of speed and torque requires the use of corresponding sensors; in order to make the motor run under different working conditions during the test, mechanical loads must be added; after the test is completed, manual data processing and curve drawing are required... All of this is quite complicated and troublesome for testers. Is there a permanent test solution?

The birth of the dynamometer

Since there is demand in the industry, corresponding products will be born in the market. Test equipment manufacturers found that most of the motor tests must be carried out under load, and with the development of embedded technology, the communication and control of sensors and instruments are becoming more and more convenient, so they integrated test instruments, sensors, and mechanical loading systems - the initial test system, dynamometer, was born.

The structure of the dynamometer is very simple, consisting of a cabinet and a test bench. The test bench is often called a dynamometer head, which generally refers to a style in which the torque speed sensor and the brake are integrated. The test bench includes a mounting base, a torque speed sensor, and a mechanical load (brake); the cabinet includes an electrical parameter tester, a motor tester, a dynamometer controller, a power supply, etc. The functions of each component are as follows:

l Mounting base - used for installation and fixation of the motor under test;

l Torque and speed sensor: used to collect the speed and torque of the motor under test;

l Mechanical load - generally a brake is used, but sometimes a motor is used to provide a reverse rotation torque to the motor under test, absorb the power of the motor under test during operation, realize the "loading" of the motor under test, and simulate its actual operating conditions;

l Electrical parameter tester - used for collecting and displaying electrical parameters such as voltage, current, and electric power of the motor under test;

l Motor tester - used to collect the output signal of the torque speed sensor and digitally display the speed, torque and mechanical power of the tested motor;

l Dynamometer controller - used to control the mechanical load to output different torques;

l Power supply: used to supply power to the system and the motor under test.

For users, the dynamometer solves the most troublesome problem - loading and data collection, but the processing of test results still needs to be done manually. From the demand level, the following figure is analyzed:

In fact, the speed of motor testing based on dynamometer is still very slow, so the next generation product - motor testing system was developed.

Self-cultivation of a motor test system

An ideal motor test system is one in which the tester only needs to focus on the input (setting the test environment parameters) to obtain the output (test results and reports) when conducting each test project. Therefore, the dynamometer has been upgraded again, and the automation of control, loading and measurement has been realized by introducing PLC and industrial computer:

At this point, the basic framework of the motor test system has matured. Currently, this type of motor test system is the most popular, but due to user habits, many names are still kept as "dynamometers". This type of system can already meet the needs of most common motor test items.

The future of industry and specialization

The basic framework of the current motor test system has matured, so where should the next development direction go? Let's go back and analyze the motor as a test object. The motor family is very large. As mentioned earlier in the article, different types of motors have different characteristics and need to pay attention to different performance points. For example, servo motors focus on their control linearity and control speed, household appliance motors focus on their efficiency, and electric vehicle motors focus on their power density and high-efficiency zone... In the future, the motor test system will also follow the different motor industry applications to supplement and improve the test functions.

With its in-depth understanding and long-term accumulation in the fields of power analysis and motor measurement, and integrating the concepts of instrument design and system integration, ZLG Zhiyuan Electronics has broken the performance bottleneck of traditional dynamometers and launched the MPT series motor testing system, which can create the most professional industry-specific motor testing solutions for users and maximize the satisfaction of current and future industry users' motor testing needs.