Why is a DC Motor Self-Starting vs. an AC Motor?

Thread starter Sheldon()
Start date Jun 2, 2012
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Ac Ac motor Dc Dc motor Motor

In summary, the main difference between a DC motor and an AC motor is the type of current they use to power the motor. A DC motor is considered self-starting because it does not require any external devices to start and run. This is made possible by the presence of a commutator and brushes. On the other hand, an AC motor is not self-starting and requires an external device to create a rotating magnetic field. However, it is possible to make an AC motor self-starting by using a starter or a capacitor, depending on the design and construction of the motor.

Jun 2, 2012

Sheldon()

Can someone explain me why dc motor is self starting differ of ac who is not self starting motor?

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Jun 2, 2012

Bob S

The conventional dc motor has a commutator and dc current flowing in the armature, while an ac single-phase induction motor has an induced ac current in the rotor (squirrel cage).

1. What is the main difference between a DC motor and an AC motor?

The main difference between a DC motor and an AC motor is the way in which they convert electrical energy into mechanical energy. DC motors use direct current (DC) to power the motor, while AC motors use alternating current (AC).

2. Why is a DC motor considered self-starting?

A DC motor is considered self-starting because it does not require any external devices or mechanisms to start and run. The direction of rotation of a DC motor is determined by the direction of the current flow, which can easily be controlled by using a switch or a controller.

3. How does a DC motor start on its own?

A DC motor starts on its own due to the presence of a commutator and brushes. The commutator is a rotating switch that changes the direction of the current flow through the armature, causing the motor to rotate. The brushes make contact with the commutator and deliver the current to the armature, allowing the motor to start and run.

4. Why is an AC motor not self-starting?

An AC motor is not self-starting because it requires an external device, such as a starter or a capacitor, to create a rotating magnetic field. This rotating magnetic field is necessary for the motor to start and run. Without this external device, the motor would not be able to start on its own.

5. Can an AC motor be made self-starting?

Yes, an AC motor can be made self-starting by using a starter or a capacitor. These devices help to create a rotating magnetic field in the motor, allowing it to start on its own. However, not all AC motors can be made self-starting and it depends on the design and construction of the motor.