Necessity of Starter- DC Motor - Electrical Machines 1

TL;DR

A starter is crucial to limit high starting currents in motors to prevent damage due to low initial back EMF.

Transcript

click the bell icon to get latest videos from akira hello friends in this video we are going to study what is the necessity of starter basically starter is nothing but a device which starts the motor the device is necessary because if it is not used then the motor will be directly connected to the rated current this at starting current is very high... Read More

Key Insights

• ✋ Starters are crucial to limit high starting currents in motors.
• ✋ High initial currents can damage motor components like brushes and commutators.
• 🎮 Back EMF plays a vital role in controlling armature current in motors.
• 🧑‍🦼 Series resistance in starters helps to limit current at motor start-up.
• 🧑‍🦼 Controlling armature current is essential for safe and efficient motor operation.
• 🚄 Motor speed increase leads to higher back EMF, reducing armature current flow.
• 🧑‍🦼 Series resistance is gradually reduced as the motor reaches operational speed.

Questions & Answers

Q: Why is a starter necessary for motors?

A starter is needed to limit the high starting currents that can damage motor components like brushes, commutators, and armature windings. Without a starter, the motor would be directly connected to high initial current, risking damage.

Q: How does the armature current depend on the armature resistance?

The armature current is inversely proportional to armature resistance. Lower resistance leads to higher current flow, which can be damaging at motor start-up. By increasing resistance initially, current is limited for safe operation.

Q: How does back EMF affect armature current in motors?

At motor start-up, back EMF is zero as the speed is zero. As speed increases, back EMF also increases, controlling armature current. Back EMF prevents excessive current flow once the motor reaches operational speeds.

Q: Why is a series resistance used in motor starters?

A series resistance is used in starters to initially limit high armature currents by increasing resistance. As the motor speed increases, the resistance is gradually decreased until the motor reaches its operational speed and back EMF controls the current.

Summary & Key Takeaways

• Starters are devices essential for motors to limit high starting currents, preventing damage.

• High starting currents can damage brushes, commutators, and armature windings.

• By controlling armature current with a series resistance, motors can start safely and efficiently.