STAR DELTA STARTER: STAR DELTA STARTER

INTRODUCTION TO STAR DELTA MOTOR STARTER

STAR DELTA STARTER PANNEL

Most induction motors are started directly on line, but when very large motors are started that way, they cause a disturbance of voltage on the supply lines due to large starting current surges. To limit the starting current surge, large induction motors are started at reduced voltage and then have full supply voltage reconnected when they run up to near rotated speed.

Working Principle Of Star-Delta Starter

This is the reduced voltage starting method. Voltage reduction during star-delta starting is achieved by physically reconfiguring the motor windings as illustrated in the figure below. During starting the motor windings are connected in star configuration and this reduces the voltage across each winding.This also reduces the torque factor of three.

Scheme - Working Principle of Star-Delta Starter

Star Delta starters are probably the most common reduced voltage starters. They are used in an attempt to reduce the start current applied to the motor during start as a means of reducing the disturbances and interference on the electrical supply.

Traditionally in many regions, there has been a requirement to fit a reduced voltage starter on all motors greater than 5 HP(4 KW). The Star Delta ( or Wye/ Delta) starter is one of the lowest cost electromechanical reduced voltage starters that can be applied.

POWER CIRCUIT OF STAR DELTA STARTER