What is meant by commutator in physics?

A device that reverses the direction of flow of current through a circuit is called a commutator. In electric motors, the split ring acts as a commutator.

What is commutator short answer?

A commutator is a rotatory electrical switch that reverses the direction of current between the rotor and the external circuit periodically. The reversal of the current each half-turn gives rise to a steady rotating torque.

What is the function of commutator?

On DC and most AC motors the purpose of the commutator is to insure that the current flowing through the rotor windings is always in the same direction, and the proper coil on the rotor is energized in respect to the field coils.

What is another name for commutator?

Synonyms for commutator in English commutator; reverser; current-reverser; switch.

Is commutator convert DC to AC?

Commutator converts the Alternating to direct current in a DC generator. The alternating current generated in the armature windings of the generator gets converted to direct current after it passes through the commutator and the brushes. Was this answer helpful?

Why commutator is used in DC motor?

The function of a commutator in a dc generator is to collect the current generated in armature conductors. While in the case of a dc motor, the commutator helps in providing current to the armature conductors. A commutator consists of a set of copper segments which are insulated from each other.

What is commutator and brushes?

To keep the torque on a DC motor from reversing every time the coil moves through the plane perpendicular to the magnetic field, a split-ring device called a commutator is used to reverse the current at that point.

What is the role of a commutator in a simple electric motor?

The function of commutator rings is to reverse the direction of current flowing through the coil every time coil just passes the vertical position during a revolution. Was this answer helpful?

Is commutator a rectifier?

In a DC generator, the commutators act as a mechanical rectifier that converts the alternating current from the windings to direct current in the external load circuit. In a DC motor, the commutator provides the electrical current to the windings by reversing the direction of the current.

Why is commutator made of copper?

The brushes in brushed commutators are usually made of either copper or carbon. Carbon brushes wear more evenly, cause less sparking, and do less damage to the conductive metal segments. Copper brushes are better suited for very low voltage and high current, however.

How does commutator reverse current?

So the current in the coil becomes opposite. Thus the forces again reverse which makes the coil to continue it’s rotation along a single direction. So the commutator reverses the current in every half turn producing a steady torque and the armature coil rotates in a single direction.

What is rotor and armature?

Also by definition, the rotor includes all of the rotating electrical parts. The field of a machine is the part that generates the direct magnetic field. The current in the field does not alternate. The armature winding is that which generates or has an alternating voltage applied to it.

What is difference between commutator and slip rings?

Slip rings are used in AC motors to provide a continuous transfer of power whereas the commutators are used in DC motors to reverse the polarity of the current in the armature windings.

What is the function of armature?

The armature’s role is twofold. The first is to carry current across the field, thus creating shaft torque in a rotating machine or force in a linear machine. The second role is to generate an electromotive force (EMF).

How do you make a commutator?

Why mercury is used in commutator?

Replacing the slip rings with pools of mercury — a conducting fluid — reduces commutator noise and friction, enabling commutator use for small weaker animals. OEM machinery manufacturers are discovering the benefits of using a mercury swivel commutator in their designs.

What is commutation in dc machines?

The commutation in DC machine or more specifically commutation in DC generator is the process in which generated alternating current in the armature winding of a dc machine is converted into direct current after going through the commutator and the stationary brushes.

What are brushes in a motor?

A carbon brush, also known as a motor brush, is the small part of the motor that conducts electrical current between the stationary wires (stator) and the rotating wires (rotor) of a motor or generator. The brush is typically made up of one or more carbon blocks and can come with one or more shunts or terminals.

What is armature in electric motor?

An armature is a device through which electric current is passed for generating torque (rotor). The current that passes through the rotor is sometimes called the armature current. The word “armature” refers to a device through which electric current is passed for generating torque.

What is back EMF?

Back EMF is the system in the coil of an electric motor that opposes the current flowing through the coil, when the armature rotates. When the speed varies, the winding characteristics may fluctuate, resulting in variation of back EMF.

What are the 3 types of DC motors?

  • Series DC Motor.
  • Shunt/Parallel DC Motor.
  • Compound DC Motors.
  • Permanent Magnet DC Motor.

What is commutator made of?

A commutator consists of a set of copper segments, fixed around the part of the circumference of the rotating machine, or the rotor, and a set of spring-loaded brushes fixed to the stationary frame of the machine.

What produces DC current?

direct current, abbreviation DC, flow of electric charge that does not change direction. Direct current is produced by batteries, fuel cells, rectifiers, and generators with commutators.

What is dc motor working principle?

When kept in a magnetic field, a current-carrying conductor gains torque and develops a tendency to move. In short, when electric fields and magnetic fields interact, a mechanical force arises. This is the principle on which the DC motors work.

Why do DC motors have brushes?

They can either be graphite or precious metal brushes which have electrical motor connections. To supply power to the rotor we put in place a brush system and each of the brushes have a direct voltage symbol (+/-). The brushes are connected to the commutator bars which allows the current to flow into the winding.

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