Fourth, the servo motor
The servo motor is divided into two categories: DC and AC servo motor. It can control the speed and position with high precision, and convert the voltage signal into torque and speed to drive the control object. The servo motor rotor speed is controlled by the input signal and can be quickly reacted. It is used as an actuator in the automatic control system, and has the characteristics of small electromechanical time constant, high linearity, and starting voltage, which can convert the received electrical signals. An angular displacement or angular velocity output on the motor shaft. Its main feature is that when the voltage signal is zero, there is no rotation phenomenon, and the rotation speed decreases uniformly with the increase of the torque.
Five, how to choose
Secondly, it is necessary to select the appropriate load according to the properties of the measured motor such as the speed, torque, power and the load suitable scene. Each type of load has its own advantages and disadvantages:
1. Eddy current, suitable for high speed and high power occasions, the maximum speed can support 30,000 rpm at 5kw;
2. Magnetic powder braking, low price, mainly used in low-speed and high-power applications, but need to consider heat dissipation, low precision, there will be zero drift;
3. Hysteresis brake, suitable for high speed and low power applications, the torque range is very small, the power of about 5kw can only measure 30N.m;
4. Servo motor, suitable for occasions with high precision requirements, good test repeatability, support for feed-type load. The range of speed and torque is not fixed, and the corresponding load motor can be flexibly selected according to the characteristics of the motor to be tested.
Therefore, according to the test requirements of the motor under test, it is determined by selecting the load brake by comparing the characteristics of each type of load.
