AUTOMATIC AUTO-TRANSFORMER STARTER

• L1: This represents the line voltage input to the control circuit.
• Circuit Breaker/Disconnect: The symbol connected to L1 is a circuit breaker or disconnect switch, providing overcurrent protection and a means to isolate the control circuit.
• Overload Relay (I): This device protects the motor or load from excessive current. The contact shown (between terminals 12 and 14) is a normally closed (NC) overload contact that opens if an overload condition is detected.

• Emergency Stop (ES): This is a normally closed (NC) push button used for immediate shutdown of the system in an emergency.
• STOP Button: This is a normally closed (NC) push button used for routine stopping of the circuit.
• START Button: This is a normally open (NO) push button used to initiate the operation of the circuit.

• Main Contactor (M) Auxiliary Contact: This is a normally open (NO) contact associated with the main contactor 'M'. It typically serves as a holding contact (or seal-in contact) to maintain the circuit's energized state after the START button is released.
• Timer (T) Contact: This is a normally open (NO) time-delay contact, which will change state after a set period once its associated timer coil is energized. It's used for sequencing operations.
• RUN Indicator/Coil: This represents either a pilot light indicating the "RUN" status of the system or the coil of a relay/contactor that controls the "RUN" state of the auto-transformer.

The handwritten notes (53-19) and (43-29) likely indicate cross-references or connections to other parts of the complete circuit diagram.