Star Delta Starter Explained with Siemens LOGO PLC | Full Wiring & Operation

Hello friends,
welcome back to our channel. In today’s video, we are going to learn about the Star-Delta Starter wiring using Siemens LOGO PLC. This method is widely used for starting three-phase induction motors smoothly and efficiently."

[Section 1 – Incoming Supply]
"Here, you can see the incoming three-phase supply: Red, Yellow, and Blue phases, along with Neutral. The supply is first connected through an MCB for protection against overload and short circuit."

[Section 2 – PLC Connection]
"From the MCB, the power lines are connected to the Siemens LOGO PLC. This PLC is used to control the logic sequence of the Star-Delta starter, ensuring the motor runs in Star connection first and then shifts to Delta connection automatically."

[Section 3 – Contactors]
"Next, we have three contactors – Main, Star, and Delta.

The Main Contactor connects the motor to the power supply.

The Star Contactor connects the motor windings in Star configuration for smooth starting with reduced voltage.

The Delta Contactor connects the windings in Delta configuration for full-load running after the motor picks up speed."

[Section 4 – Overload Relay]
"An overload relay is also connected in the circuit. This provides protection to the motor against overheating and excessive current."

[Section 5 – Motor Connection]
"Here you can see the three-phase motor connected to the output terminals of the contactors. Initially, the motor runs in Star connection, and after a preset time delay, the PLC shifts the connection to Delta for normal operation."

[Section 6 – Push Buttons & Indicators]
"On the right side, you can see the Start and Stop push buttons.

The Green button is for Start.

The Red button is for Stop.

We also have indicator lamps:

The Green lamp shows Run status.

The Yellow lamp shows Trip condition in case of overload or fault."

[Section 7 – Working Principle]
"Here’s how it works:
When we press the Start button, the PLC energizes the Main and Star contactors, and the motor starts in Star mode. After a few seconds, the PLC switches off the Star contactor and switches on the Delta contactor. Now the motor runs in Delta connection at full load. The Stop button or an overload condition will immediately cut off the motor supply, ensuring protection."