Starting and control of three-phase asynchronous motors

 

Starting and control of three-phase asynchronous motors

The three-phase asynchronous motor is the most widely used electric motor worldwide in industrial facilities and large buildings. Simple in terms of design and handling, flexible in diverse fields of application and economical to operate. It is the most favourable drive solution in terms of price and quality.

Characteristic for the three-phase motor is the high current load on the mains supply with direct-on-line starting. High starting and surge currents result when the full voltage is applied, causing troublesome voltage dips on the mains supply and transient torque effects in mechanical systems.

Since the invention of the three-phase motor – more than a century ago (1889) –, start-up solution concepts have been devised, which have intended to eliminate the unpleasant side-effects. Yet exactly which of these solution concepts fulfil the desire for satisfactory start-up and optimum operating performance is dependent on the application and ultimately the economic aspects as well.

To facilitate a simplified overview, the four most important and most well-known start-up methods for starting and controlling three-phase asynchronous motors used in practice are presented. In the process, we deliberately dispense with the description of the devices and functions, and general basic knowledge of electrical drive engineering is assumed

Download Starting and control of three-phase asynchronous motors 

 

 

 

Starting and control of three-phase asynchronous motors

The three-phase asynchronous motor is the most widely used electric motor worldwide in industrial facilities and large buildings. Simple in terms of design and handling, flexible in diverse fields of application and economical to operate. It is the most favourable drive solution in terms of price and quality.

Characteristic for the three-phase motor is the high current load on the mains supply with direct-on-line starting. High starting and surge currents result when the full voltage is applied, causing troublesome voltage dips on the mains supply and transient torque effects in mechanical systems.

Since the invention of the three-phase motor – more than a century ago (1889) –, start-up solution concepts have been devised, which have intended to eliminate the unpleasant side-effects. Yet exactly which of these solution concepts fulfil the desire for satisfactory start-up and optimum operating performance is dependent on the application and ultimately the economic aspects as well.

To facilitate a simplified overview, the four most important and most well-known start-up methods for starting and controlling three-phase asynchronous motors used in practice are presented. In the process, we deliberately dispense with the description of the devices and functions, and general basic knowledge of electrical drive engineering is assumed

Download Starting and control of three-phase asynchronous motors