Is there a relationship between the torque size and speed of three phase asynchronous motor?

Today we will talk about the relationship between torque and speed in three phase asynchronous motors.

For any number of poles of electric motor ,relatively high speed and large torque are the more ideal results for dragging loads.

How to determine and weigh the relationship between the two is the key element of electric motor design and adaptability to actual working conditions.

Starting torque, rated torque and maximum torque are the main performance indicators of electric motor .

Starting torque reflects the starting ability of the electric motor, maximum torque reflects the overload ability of the electric motor, and rated torque is the specific embodiment of the normal working ability of the electric motor.

For three phase asynchronous motor, the relationship between the size of torque corresponding to different speed conditions of the electric motor can be described visually through specific characteristic curves, reflecting the speed of the electric motor.

On the one hand, It can be carried out through the actual value of speed,

on the other hand, It can be qualitatively described through the rate of difference, the greater the rate of difference, it indicates that the speed of the electric motor is more different from the synchronous speed.

In order to meet the application needs of some special occasions, there are special The high turndown motor, compared with the same number of poles and the same power ordinary motor.

The high turndown motor has a smaller blocking current, can meet the normal operation from zero speed to rated speed, and the motor stable operation speed range is wider.

From the analysis of the law of motor operation,

its starting torque is generally greater than the rated torque, designed in accordance with the actual operating conditions; the maximum torque is a test of the electric motor's ability to adapt to overload conditions during operation, but also larger than the rated torque.

From the characteristic curve of three phase asynchronous motor torque and speed can be seen,

from the moment the motor starts, the motor torque increases with the speed, when the electric motor speed reaches a certain state close to the synchronous speed, the electric motor torque also reaches the peak.

As the electric motor speed increases again, the electric motor torque shows a decreasing trend, when the electric motor speed is synchronized with the rotating magnetic field, the electric motor torque is zero, which is It is the working principle and characteristics of asynchronous motor.

Under the rated operating conditions of the three phase asynchronous motor, the speed of the electric motor is very close to the speed of the corresponding stator rotating magnetic field, i.e., the motor has a very low rate of rotation.

Under normal operating conditions, most of the cage motors have a turndown rate of no more than 10% at full load, when the corresponding rotor impedance is mainly resistive and has nothing to do with the turndown rate;

in addition, the rotor current is almost proportional to the turndown rate because the rotor winding is in a short circuit.

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Please kindly check the products as follows

single phase motor: YC, YCL with cast iron body and ML , MY motor with Aluminium body

Three phase motor : IE1, IE2, IE3 motor for both cast iron body and Aluminium body

Brake motor: DC brake motor and AC brake motor

VFD motor : frequency variable drive motors.

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