Tag: ac generator

The working of a generator in based on the phenomenon of electromagnetic induction.

The laws of electromagnetic induction has been used in the construction of a electric generator. In electric generator, emf is induced by changing the flux.
Galvanometer is used to detect current. So, no use of electromagnetic induction.
Voltmeter is used to measure voltage. Again, no use of electromagnetic induction.
Electric motor changes electrical energy into mechanical energy, which has no use of laws of electromagnetic induction.

Answer is D.

Electromagnetic induction is a process where a conductor placed in a changing magnetic field (or a conductor moving through a stationary magnetic field) causes the production of a voltage across the conductor. This process of electromagnetic induction, in turn, causes an electrical current - it is said to induce the current.
Hence, the D.C. generator is based on the principle of electromagnetic induction.

Answer is B.

The electric generator is devised to convert mechanical power into electrical power. Permanent magnet (PM) current converts into electrical energy through the interaction of two magnetic fields. One field is produced by a permanent magnet assembly, the other field is produced by an electrical current flowing in the rectangular coil ABCD, through the brushes and split-ring commutators. These two fields result in a torque which tends to rotate the coil. As the coil turns, the current in the winding is commutated to produce a continuous torque output. 
The split ring commutator is made from 2 pieces of copper that are held apart in the center from touching each other. They look like a copper ring split in the middle. The effect of using split rings in a electric generator is that the direction of the current flowing in the coil is reversed and DC current is generated.

If the speed of rotation of armature coil is increased in an AC generator

Electric generator, also called dynamo, any machine that converts mechanical energy to electricity for transmission and distribution over power lines to domestic, commercial, and industrial customers. Generators also produce the electrical power required for automobiles, aircraft, ships, and trains.A feature common to both AC and DC generator is Mechanical energy is converted to electrical energy

In an AC generator,  Magnetic flux $= NAB\sin\phi$

A dynamo converts mechanical energy into electrical energy.

The slip rings allow the transfer of alternating e.m.f. induced in the rotating coil to the external circuit. Each ring is connected to one end of the coil wire and is electrically connected to the external circuit via the conductive carbon brushes.