What is the purpose of a auto transformer starter?
An auto-transformer starter makes it possible to start squirrel-cage induction motors with reduced starting current, as the voltage across the motor is reduced during starting. In contrast to the star-delta connection, only three motor leads and terminals are required.
What is the main disadvantage of open transition auto transformer starter?
1) The autotransformer starter limits significantly the inrush current. 2) It is used for large motors, in which start by direct connection to the network is not possible. For large motors also the star-delta starter cannot be used, especially if they are started with a significant load.
What is the advantages of auto transformer starter for induction motor?
Advantages of autotransformer starter: The autotransformer’s most powerful ratio is between 65 and 80 percent. The torque per ampere of supply current is maximum. The current in the motor is greater than the current in the supply. It is less expensive.
What is another name for autotransformer?
Variac Trademark The term variac has become a genericised trademark, being used to refer to a variable autotransformer.
What is auto transformer method?
In this method, an auto-transformer is placed in series with the motor during staring. The transformer action reduces the voltage applied to the motor terminals. Because of the transformer action, the line current is less than the motor current. Thus, this method gives the highest motor torque per line ampere.
What is the advantage and disadvantage of auto transformer?
1. Because the primary and secondary windings of the autotransformer are physically connected, the supply and output voltage are not insulated from each other. In an autotransformer, the total power transmitted from the primary to the secondary does not actually pass through the whole winding.
What is a three-phase autotransformer starter?
An Autotransformer Starter is suitable for both star and delta connected motors. In this method, the starting current is limited by using a three-phase autotransformer to reduce the initial stator applied voltage.