Why Use Servo Motor as Test Load?

Dynamometer is mainly divided into two parts: cabinet and frame, while the frame mainly has the motor under test, torque speed sensor, mechanical load. Currently, servo motors are mostly used as loads. Servo motors convert electrical signals into torque and speed to drive the control object. Servo motor rotor speed is controlled by the input signal, and can respond quickly, in the automatic control system, used as an executive element, and has a small electromechanical time constant, high linearity, starting voltage and other characteristics.
The servo motor can be used for motor-to-motor towing. The common DC bus adopts a separate rectifier/feedback device to provide power for the system, and the inverter for speed regulation is directly connected to the DC bus, when the system is working in the electric state, the inverter obtains power from the bus. When the load is dragged by the measured motor in the reverse direction, the servo motor will become a generator, and the energy will be fed back to the power grid directly through the busbar and the feedback device, so as to achieve the purpose of energy saving and improving the reliability of equipment operation.

Then the question comes, leaving aside the servo motor inverter motor can also achieve the effect of this power feedback. In fact, this is the case, for inverter motors pay more attention to the frequency control, inverter motors can be based on the needs of the work, by changing the frequency of the motor to achieve the required speed, but this variable frequency drive motor does not have a better torque characteristics, it is just to overcome the ordinary motor does not adapt to the PWM modulation of the analog sinusoidal alternating current needs.

When measuring the load characteristics of a motor, this test should be performed as quickly as possible to minimize the temperature change of the motor during the test. In contrast, the superiority of the servo motor is highly interpreted. Load changes require the load motor for a given waveform to make a rapid response, it not only has a high control accuracy, fast control speed, comes with PID regulation, etc., but also can simulate the test motor load of continuous working conditions change. In the case that the speed or torque is not particularly high or low, it is recommended to use servo motor as the test load.

Servo motor as a pair of drag load, get rid of the traditional dynamometer can only be loaded one by one load point of this limitation. With this as the core, it realizes arbitrary load curve loading and waveform measurement during motor testing, meets the demand for transient measurement of motors and drives, and takes motor testing to a new level.