a question on electromagnetism??????????

Question

HOW DOES an electric motor works??????????????

Answer 1

heyya dear....

An electric motor uses the attractive and repulsive forces between magnetic poles to twist a rotating object (the rotor) around in a circle. Both the rotor and the stationary structure (the stator) are magnetic and their magnetic poles are initially arranged so that the rotor must turn in a particular direction in order to bring its north poles closer to the stator's south poles and vice versa. The rotor thus experiences a twist (what physicists call a torque) and it undergoes an angular acceleration--it begins to rotate. But the magnets of the rotor and stator aren't all permanent magnets. At least some of the magnets are electromagnets. In a typical motor, these electromagnets are designed so that their poles change just as the rotor's north poles have reached the stator's south poles. After the poles change, the rotor finds itself having to continue turning in order to bring its north poles closer to the stator's south poles and it continues to experience a twist in the same direction. The rotor continues to spin in this fashion, always trying to bring its north poles close to the south poles of the stator and its south poles close to the north poles of the stator, but always frustrated by a reversal of the poles just as that goal is in sight.

Answer 2

Motor is exactly reverse of a generator. So read my article on generator.

Generator putout current and you have to put the current in the motor.
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Principle of a Generator and Alternator
By
minootoo


When a magnetic field is disturbed by a wire a current is produced in the wire.

So if you have a coil of wire and a horse shoes magnate, both arranged on a frame so that coil can rotate, in side the prong of the magnate, it will have current generated inside the coil.

All that needs to be done is get this current to an appliance, say a light bulb or a galvanometer or a heating coil……

This is done by a mechanical arrangement.

The magnate is attached to a frame it also has a hole through which a shaft passes without touching the magnate or rubbing. This shaft carrying two composite disc made of copper and, non conductive material, coil and two bearing, one at each end of the shaft. This assembly is made to rotate in side the magnate. Two ends, from the coil are attached to two discs on the side of the disc. One of the discs has the hole to thread coil wire, without touching the first disc. A hand crank is mounted on the shaft outside the frame. Frame will carry two additional wires that can rest on the edge of the disc (technically they are call brush because they brush the disc as it turns) so the current can be conducted, current is produced in the coil when the shaft is turned using the crank.

These two wires can now be taken to the appliance, say a suitable light bulb. On turning the crank the bulb will light up.

This arrangement will produce a DC or direct current. The contraption other then bulb and extra long wire is called the generator.

Alternator

An alternator is just a generator but coil does not rotate, the magnate is rotated. Shaft will be heavy short and it will have one good strong bearing. It will not need disc or the brushes. It will produce an AC or alternating current.
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How is current induced in a coil by an oscillating a bar magnet
By
Minootoo

In any wire or substances there is a random motion of electrons.

The magnet's oscillation near a coil of wire or even a single loop brings order to the random motion; this disturbance causes a collision of a kind changing the direction of the motion.

Answer 3

The Electric motor works on the principle of an electron current interaction with a magnetic field.The motion of the electric power field reacts with the magnetic field of the magnet in the motor .The action produces a reaction causing a mechanical moving force.Thus, we then have a spinning mechanical device called electric motor.
It can be concluded that an electromotive force transfers to a mechanical motive force when electric field interacts with a magnetic field. And the process is also reversible.

Answer 4

this ans is really very long