The three-phase asynchronous motors main technical parameters include Power, voltage, current, speed, power factor, efficiency, etc.,
For any motor, when the input voltage changes, other performance parameters will change to a certain extent.
The correlation between power, voltage, and torque of the three-phase asynchronous motor
The main technical parameters of a three-phase asynchronous motor include power, voltage, current, speed, power factor, efficiency, etc. For any motor, when the input voltage changes, other performance parameters will change to a certain extent.
The three-phase asynchronous motor is an induction motor, and the rotor speed is slipped from the stator rotating magnetic field speed, so the rotor speed will always be lower than the rotating magnetic field speed. During the starting process of the motor, the current is large, but the power factor is small, and the torque in the corresponding state is also small.
01: The relationship between torque and voltage
Torque is a parameter that characterizes the driving ability of a motor product. The output torque of the motor shaft and the no-load torque constitute the electromagnetic torque of the motor. The electromagnetic torque is the product of the electromagnetic force and the force arm. Relative to the output torque, the no-load torque is relatively small. Under the premise of ignoring the no-load torque, the electromagnetic torque of the motor is proportional to the square of the voltage and inversely proportional to the frequency of the power supply. The qualitative description is that the electromagnetic torque is positively correlated with the voltage, and negatively correlated with the power frequency. When the power supply voltage is insufficient, the drive capacity of the motor will decrease. The intuitive relationship is that when the power supply voltage is insufficient, especially high-power motors, there will be a humming state that cannot be started normally.
02: The relationship between power and torque
The output power of the motor is a constant multiple of the product of torque and speed; for motors of the same power, the torque of a multi-pole low-speed motor is large, on the contrary, the torque of a low-pole high-speed motor is small. This relationship applies to most motor products.
Combined with the analysis of the relationship between motor power and torque and speed, we can easily understand the performance of different gears of the car, that is, through the change of transmission ratio, adjust the appropriate traction to meet the needs of the vehicle under different working conditions; also A better understanding of the principle of transmission. Automobile transmission ratio (speed ratio) refers to the ratio of the speed of the two transmission mechanisms before and after the transmission in the transmission system of the automobile. In the same model, the speed ratio of the main drive is a fixed value, while the speed ratio of the transmission has different values depending on the gears used.
The belt and gear transmission in the motor products are all concrete manifestations of the adjustment of the correlation between torque and speed. On some occasions, a larger torque is required, which can be achieved by a device whose rotation speed is lower than that of the motor (such as a cable car). Similarly, in some cases, a larger speed is required, which may be achieved by a speed increase. The device realizes the acceleration of the speed, but the torque obtained at this time is smaller.
Welcome to consult SDT Transmission™ if you have more questions: