When we place a current carrying conductor in a magnetic field emf is induced in a coil. we can knoe it by connecting voltmeter.
when rotor excited by ac voltage , the rotor current flow , and a magnetic field is produced .the rotor magnetic field induced an emf in the stator coils by transformer action.the effective voltage induced in any stator coildepend upon the angular position of te coil's axis w.r.t rotor axis sthitaprajna.rath@gmail.com
You mean ac coil, the secondary coil, of a transformer? Then for the purpose of rectification, that is , for changing ac into dc, a diode is connected in series with the secondary coil of the transformer.
equation of ac machine
The distance between the two sides of an individual coil of and AC armature winding id termed the coil pitch.
take care of the problem of induced AC field current due to armature reaction /Omara
AC generator, the brushes run on slip rings which maintain a constant connection between the rotating coil and the external circuit. This means that as the induced emf changes polarity with every half-turn of the coil, the voltage in the external circuit varies like a sine wave and the current alternates direction. DC generator, the brushes run on a split-ring commutator which reverses the connection between the coil and the external circuit for every half-turn of the coil. This means that as the induced emf changes polarity with every half-turn of the coil, the voltage in the external circuit fluctuates between zero and a maximum while the current flows in one constant direction
when rotor excited by ac voltage , the rotor current flow , and a magnetic field is produced .the rotor magnetic field induced an emf in the stator coils by transformer action.the effective voltage induced in any stator coildepend upon the angular position of te coil's axis w.r.t rotor axis sthitaprajna.rath@gmail.com
BECAUSE YOU NEED AC EFFECT TO INDUCE EMF IN TO SECONDARY WINDING.OR DC PULSING.
AC generator, the brushes run on slip rings which maintain a constant connection between the rotating coil and the external circuit. This means that as the induced emf changes polarity with every half-turn of the coil, the voltage in the external circuit varies like a sine wave and the current alternates direction. DC generator, the brushes run on a split-ring commutator which reverses the connection between the coil and the external circuit for every half-turn of the coil. This means that as the induced emf changes polarity with every half-turn of the coil, the voltage in the external circuit fluctuates between zero and a maximum while the current flows in one constant direction
When you wind a current carrying wire into a coil, it causes the concentration of the magnetic field line to intensify. Depending on which pole of the magnet is in the up position, the wire will move towards or bend away from it.
when switch is closed then ac current flows in circuit. ac current is varies with the time as we changes the value of resistances ,current also changes because of this magnetic flux is introduced and result in induced emf generating in same circuit.
You mean ac coil, the secondary coil, of a transformer? Then for the purpose of rectification, that is , for changing ac into dc, a diode is connected in series with the secondary coil of the transformer.
equation of ac machine
Back EMF.
only in dc motor...
The coil are responsible for transferring of cool air trough the unit
An emf is induced in a coil as a result of (1) a coil cutting through a magnetic field, or (2) a magnetic field cutting through a coil. As long as there is relative motion between a conductor and amagnetic field, a voltage will be induced in the conductor. That part of a generator that produces the magnetic field is called the field. That part in which the voltage is induced is called the armature. Forrelative motion to take place between the conductor and the magnetic field, all generators must have two mechanical parts - a rotor and a stator. The ROTor is the part that ROTates; the STATor is the part that remains STATionary. In a dc generator, the armature is always the rotor. In alternators, the armature may be either the rotor or stator. ROTATING-ARMATURE ALTERNATORSThe rotating-armature alternator is similar in construction to the dc generator in that the armature rotates in a stationary magnetic field as shown in figure 3-1, view A. In the dc generator, the emf generated in the armature windings is converted from ac to dc by means of the commutator. In the alternator, the generated ac is brought to the load unchanged by means of slip rings. The rotating armature is found only in alternators of low power rating and generally is not used to supply electric power in large quantities.