Introduction to operation and control principle of

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Introduction to the operation and control principle of motor multi-functional power saving protection

generally, the working efficiency of motor under light load or no-load state is very low. The continuous operation of the motor must consume a certain amount of energy to provide a magnetic field. When the terminal voltage supplied to the motor is constant, the generated magnetic flux also remains constant. At the rated speed, the energy consumed by the magnetic field remains constant, independent of the torque required by the load. The energy to support the load torque depends on the electromagnetic torque. When the load torque increases, the speed of the rotor will decrease slightly (the slip rate increases), so that the induced rotor current increases to increase the electromagnetic torque. On the contrary, if the required load torque is reduced, the slip rate is reduced, and the current of the energy used by the rotor accounts for about 12% of the total energy consumption of the national economy is reduced. Users who need to buy high and low temperature impact testing machines for the stator hope to find a reliable manufacturer of high and low temperature impact testing machines, and the current is reduced accordingly. However, when the terminal voltage is constant, the current supplied by the stator to the magnetic field will remain constant under any load torque condition. As a result, the efficiency of the induction motor decreases as the load decreases

it is rare for general motors to always operate under rated conditions. The nominal value of the motors we selected is higher than the maximum demand under the driving load. When the rated voltage is input, there is room for power saving even if it operates at full load. At this time, the driving load is generally not constant. The size of the selected motor must meet the demand at its maximum load. Although the maximum load only occurs intermittently, the load at other times is much smaller. Since the torque generated by the motor is proportional to the square of the supply voltage, reducing the terminal voltage will reduce the torque. Reducing the voltage actually reduces the rated output power of the motor. It also means that the required magnetic field energy is reduced. Use this principle. Xinke's motor multi-functional power-saving protector can maintain constant motor efficiency from no-load to most load conditions. It is controlled by intelligent microprocessor without manual adjustment. In the case of light load, the voltage of the motor is automatically reduced to the minimum demand, while the speed remains constant, thus reducing unnecessary losses. If the load increases, the voltage will rise automatically to prevent the motor from stalling

it is controlled by a closed-loop feedback system, and its induction circuit compares the voltage and current waveforms passing through the motor. Because it is an inductive circuit, there is a time difference between the voltage and current waveforms. The lighter the load, the greater the lag of the current waveform. Under the same load conditions, the multi-functional power saving of the motor shall be measured based on the guide rail. The protector shall continuously monitor the phase angle between the voltage and current of the motor, and change the phase angle according to the change of load. It is controlled by using a thyristor semiconductor switching element to cut the voltage. The thyristor allows a part of the positive and negative half cycle of the power supply voltage to be supplied to the motor


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