Seven speed control methods for three-phase asynchronous motors 1

Update:05 Aug 2019
Summary:

About the knowledge of three-phase asynchronous motor, […]

About the knowledge of three-phase asynchronous motor, but how do you know the speed regulation? Today, we will introduce seven speed control methods for you.

First, the pole-changing logarithmic speed control method: This speed-adjusting method is to change the stator-to-number of the cage-type motor to change the number of stator pole pairs of the cage motor to achieve the purpose of speed regulation. The method is suitable for production machinery that does not require stepless speed regulation, such as gold

It is a cutting machine tool, elevator, lifting equipment, fan, water pump, etc.

Second, the frequency conversion speed regulation method: frequency conversion speed regulation is a speed control method that changes the frequency of the motor stator power supply, thereby changing its synchronous speed. The main equipment of the variable frequency speed control system is the inverter that provides the variable frequency power supply.

There are two major categories of flow-DC-AC inverters and AC-AC inverters. At present, most of them use AC-DC-AC inverters. The method is suitable for occasions requiring high precision and good speed regulation performance.

Third, the cascade speed control method: Cascade speed regulation refers to the adjustable additional potential in the rotor circuit of the wound-type motor to change the slip of the motor to achieve the purpose of speed regulation. Most of the slip power is absorbed by the additional potential that is strung

Receiving, recycling, and generating additional devices, returning the absorbed slip power to the grid or converting energy for use. According to the slip power absorption and utilization method, the cascade speed regulation can be divided into motor cascade speed regulation, mechanical cascade speed regulation and thyristor.

In the form of tube cascade speed regulation, thyristor cascade speed regulation is often used. The method is suitable for use on fans, water pumps and rolling mills, mine hoists and extruders.