1. According to the structure diagram of the eddy current dynamometer, the inductor is mainly composed of a rotating part and a swinging part (armature and excitation coil). The inductor on the rotor shaft is shaped like a gear and is equipped with a DC excitation coil coaxial with the rotor. When a direct current is applied to the excitation coil group, a magnetic field exists around it, and a closed magnetic flux is generated around the excitation group. It is evident that the inductor located on the left side of the winding has one polarity, while the one on the right side has the opposite polarity. When the Nanfeng dynamometer rotates, eddy currents are generated due to the periodic changes in magnetic density values. The magnetic field generated by these eddy currents interacts with the magnetic field that produces it, thereby generating a braking torque that is opposite to the test machine, causing the armature to swing. The braking force is transmitted to the measuring device through the force arm on the armature.
2. A device that uses eddy currents to generate braking torque for measuring mechanical torque. It consists of an electromagnetic slip clutch (see electromagnetic speed regulating asynchronous motor), a load cell, and a speed measuring generator. The input shaft of the tested power machinery is connected to the electromagnetic slip clutch, driving the armature to rotate. The magnetic pole is stopped by the force measuring arm installed on it, and can only swing within a certain range by one angle. With the help of a load cell, the electromagnetic torque between the armature and the magnetic pole can be directly read from this swing angle. When measuring errors such as wind and friction losses are excluded, this electromagnetic torque is equal to the output torque of the tested power machinery. Eddy current dynamometer can only generate braking torque and cannot operate as an electric motor. It is generally used to measure power machinery where the speed increases while the torque decreases, or where the torque changes while the speed remains basically unchanged.
Dynamometer function: It can arbitrarily change the load of the motor and directly measure the input voltage, current, power, output torque, speed, output power, and efficiency of the motor under no-load, load, and locked rotor conditions.