Single Phase Direct Online Starter DOL Wiring - Connections Explained and Setting the Overload

Summary

In this workshop video, Matt and Joe demonstrate the connections for a single-phase motor with a direct online starter and remote stop-start functionality. They explain the wiring connections, including the live and neutral supply, overload relay, and the start and stop button configurations. The video also covers the importance of setting the overload relay correctly according to the motor's specifications and highlights the safety features like the manual reset button for overload protection. The presentation aims to guide learners on how to make these connections in a real-world scenario.

Takeaways

• 🔌 The video discusses the connections for a single-phase motor with a direct online starter, including remote stop and start capabilities.
• 👨‍🏫 Matt and Joe previously explained the connections on a whiteboard, and this video shows the physical connections in the workshop.
• 🔑 The video demonstrates the direct online starter connections by physically showing them, starting with the line supply coming into terminal 1.
• 🔄 The line conductor from terminal 2 goes directly to the motor, and the neutral conductor from terminal 3 loops through the overload relay and back to the motor.
• 🛠️ The overload relay is crucial for protecting the motor and can be changed if needed; it's rated at approximately 13 amps in this example.
• ⚙️ The video emphasizes the importance of setting the overload relay correctly according to the motor's specifications to prevent damage.
• 🔁 There's a loop from terminal 13 to 17, indicating a normally open contact, which is essential for the start button's operation.
• 🔴 The stop button is interconnected with the overload relay, showing a direct connection from the overload to terminals 95 and 96.
• 🔵 The video highlights the importance of correctly connecting the CPC (Conductive Parts Connected) for safety and proper functioning of the electrical system.
• 🔄 The video also mentions the reset button for the overload relay, allowing for manual resetting in case of an overload condition.
• 📚 The presentation serves as a practical guide for learners to understand and make the necessary connections for a single-phase direct online motor starter.

Q & A

What is the main focus of the video script?

The main focus of the video script is to demonstrate the physical connections of a single-phase direct online (DOL) motor starter, including remote stop/start functionality and overload relay settings, as previously described in classroom drawings.

What are the key components being discussed in the video?

The key components discussed are a single-phase motor, direct online starter, remote stop/start functionality, the overload relay, and their respective electrical connections.

What is a direct online (DOL) starter, and how does it function?

A direct online (DOL) starter is a device used to start electric motors by applying the full line voltage. It includes a contactor to connect and disconnect the power supply, overload relays for protection, and start/stop buttons for operation control.

How are the line and neutral connections managed in the DOL starter setup?

The line supply comes in at connection number 1, goes out at connection number 2, and runs to the motor. The neutral conductor enters at connection number 3, loops through to number 5, and exits at connection number 6, all directed to the motor.

What is the purpose of the overload relay in the motor starter circuit?

The overload relay protects the motor from overheating due to excessive current. It ensures the motor is not damaged by cutting off the supply if the current exceeds a certain limit, which can be set using a dial on the relay.

How can the overload relay be adjusted, and why is it important?

The overload relay can be adjusted by turning a dial with a screwdriver to set it to a specific amperage. It is important to set it correctly according to the motor's rated current to ensure protection against overloads without causing unnecessary tripping.

What do connections 13, 17, and 18 signify in the DOL starter setup?

Connections 13, 17, and 18 are part of the control circuit for the start button. Number 13 is a normally open contact that loops to 17, while 18 is connected to the retaining contacts, ensuring that the motor stays on when the start button is pressed.

What is the role of A1 and A2 terminals in the DOL starter?

A1 and A2 are the coil terminals of the contactor. A1 is connected to the line (live) and A2 to the neutral. When energized, these terminals create a magnetic field that closes the contactor, allowing current to flow to the motor.

Why is it crucial to connect the neutral properly in the DOL starter circuit?

It is crucial to connect the neutral properly because if it is taken from the wrong terminal, such as the one that goes through the contactor, it may not function correctly or cause malfunction. The neutral should be taken from the permanent neutral terminal (number 3).

How does the reset function work on the overload relay?

The reset function on the overload relay allows the user to manually reset the relay after it trips due to an overload condition. This ensures the circuit can be safely re-energized after addressing the overload issue.