Torque type of three-phase asynchronous motor and its operating conditions

Update:21 Sep 2020

Motor torque is the basic load form of various working […]

Motor torque is the basic load form of various working machinery drive shafts, and is closely related to factors such as power machinery's working capacity, energy consumption, efficiency, operating life, and safety performance. Shandong Shenghua variable frequency motor manufacturer found that as a typical power machine, three-phase asynchronous motor torque is a very important performance parameter.

Three-phase asynchronous motor

Different operating conditions have different requirements for the torque performance of the motor, for example, wound rotor motors, high-slip motors, ordinary cage motors, variable frequency speed motors, etc.

The torque settings of the motor are all around the load. Different load characteristics have different requirements for the torque characteristics of the motor. The torque of the motor mainly includes the maximum torque, the minimum torque and the starting torque. The sum of the starting torque and the minimum torque is to consider the ability of the motor to respond to the changing load resistance torque during the starting process. The way of accelerating torque is reflected. The maximum torque is more often a manifestation of the overload capacity of the motor during operation.

Starting torque is one of the important technical indicators to measure the starting performance of a motor. The greater the starting torque, the faster the motor accelerates, the shorter the starting process, and the more capable of starting with heavy loads. All these indicate good starting performance. Conversely, if the starting torque is small, the starting is difficult, and the starting time is long, so that the motor windings are easy to overheat, and even unable to start, let alone heavy starting.

Different series of motors have different options for torque design due to different working conditions. The most common ones are ordinary cage motors, high torque motors corresponding to special loads, and wound rotor motors.

Ordinary cage motors have normal torque characteristics, and are generally continuous working, without frequent starting problems, but require high efficiency and low slip. The current YE2, YE3, and other high-efficiency and super-efficient three-phase asynchronous motors are representative of ordinary cage motors.