A Star-Delta Starter is a motor-starting method used mainly for three-phase induction motors to reduce the high starting current. When the motor starts, its windings are connected in Star (Y), applying a lower voltage to each winding and reducing the starting current and torque; after the motor accelerates to a suitable speed, a timer changes the connection from Star to Delta (Δ), allowing the motor to operate at its rated voltage and develop normal running torque.
⚡ Star–Delta Starter Simulation
Interactive demonstration of reduced-current starting and automatic STAR → DELTA transition
🎛️ Motor Control
MOTOR STOPPED
Speed
0
rpm
Line Current
0
A
Torque
0
%
How it works:
When START is pressed, the motor windings are initially connected in STAR (Y). This reduces the voltage applied to each winding and therefore reduces the starting current. After the selected timer period, the STAR contactor opens and the DELTA contactor closes, allowing the motor to operate at full voltage.
When START is pressed, the motor windings are initially connected in STAR (Y). This reduces the voltage applied to each winding and therefore reduces the starting current. After the selected timer period, the STAR contactor opens and the DELTA contactor closes, allowing the motor to operate at full voltage.
L1
L2
L3
🔌 Power & Contactor Diagram
⚡ Star–Delta Starter Challenge
Mission: Start the three-phase induction motor safely.
Select the correct contactors and follow the correct
MAIN → STAR → DELTA sequence.
🎮 Contactor Control
Press START CHALLENGE to energize the control circuit.
1. MAIN
2. STAR
3. ACCELERATE
4. DELTA
M
MAIN
OFF
Y
STAR
OFF
Δ
DELTA
OFF
Score: 0
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Attempts: 0
Current
0 A
Speed
0 rpm
Torque
0%
Engineering rule:
The motor starts in STAR (Y) to reduce starting current. After acceleration, STAR must be disconnected before DELTA (Δ) is connected. Never energize STAR and DELTA simultaneously.
The motor starts in STAR (Y) to reduce starting current. After acceleration, STAR must be disconnected before DELTA (Δ) is connected. Never energize STAR and DELTA simultaneously.