Star-Delta starter
EEE
Star-Delta starter is used to start a three-phase induction motor at reduced voltage, which lowers the starting current and allows the motor to gradually reach full speed. Initially, the motor starts in a star (Y) connection, drawing less current. Once the motor reaches around 40% of its full speed, a timer switches the connection to delta (Δ), enabling the motor to run at full voltage and develop full torque.
How It Works
1. Starting Phase (Star Connection):
The motor is first connected in a star (Y) configuration.
In this connection, one end of each motor coil is joined at a common neutral point.
The voltage applied to each coil is reduced, which lowers the starting current.
Reduced starting current minimizes stress on both the motor and the power system.
2. Transition Phase (Timer Operation):
A timer controls the switching process after a preset delay (usually a few seconds).
When the motor reaches a certain speed, the timer disconnects the star connection.
3. Final Phase (Delta Connection):
The connection is switched to delta (Δ).
In delta configuration, each coil receives full line voltage.
The motor now runs at full speed and develops full torque.
Tags: Star-Delta Starter reduces the starting current of a three-phase motor by starting in star and then switching to delta connection.