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Cycloned
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I just don't understand how it does, because I never noticed the terminals change positions.
I understood how DC generators work, but not AC.
I understood how DC generators work, but not AC.
ZapperZ said:Take a loop of wire connected to an ammeter, and spin it inside a magnetic field. Look at sign of the current.Zz.
Naty1 said:In a dc generator, current is forced to flow in one direction; in an a/c generator is it allowed to flow in two. A/C power is widely used because it can be transmitted much more economically via step up power transformers...reducing current flow and reducing transmission wire size and power losses...
Remove the rectifiers (diodes) which prevent reverse current flow in a typical generator and you change a dc to an ac generator...
See here for a more complete discussion and diagram:
http://en.wikipedia.org/wiki/Alternator#Principle_of_operation
generators and alternators are slightly different...see the bottom of the WIKI page for further information.
There are different types of generators, see commutators to understand how current flow direction may be governed:
http://en.wikipedia.org/wiki/Commutator_(electric )
Actually not. High quality loudspeakers have moving voice coils in a uniform magnetic field. In this case, a current in the coil moves the speaker cone, but moving the coil will not generate a voltage.thedore said:Loud speakers are also an example of this. They consist of a coil of wire in a magnetic field. The coil moves when a current passes through it. If the cone is moved they will generate a voltage. .
jtbell said:No, in an AC generator, the coil keeps on rotating in the same direction. As the coil rotates, the magnetic flux goes through the coil first in one direction, then the other, as "seen" from the point of view of the coil. The changes in the magnetic flux through the coil alternate in direction, therefore so does the induced current.
Cycloned said:I just don't understand how it does, because I never noticed the terminals change positions.
I understood how DC generators work, but not AC.
Phrak-Phrak said:He's correct, Bob. Moving the coil in the magnetic field will generate a potential across the coil.
Bob S said:Phrak-
Moving a coil in a uniform magnetic field does not produce a voltage, because the voltage induction process is based on the Faraday induction law in integral form:
V = -d/dt[N∫B·n dA] = -N·A·dB/dt = -N·A·(∂B/∂x)(dx/dt)
where A and N are the area and # of turns in the coil, and dx/dt is the coil displacement velocity. If B is a uniform field, then ∂B/∂x is zero, and the induced voltage V is zero. The loudspeaker works on the principle of the Lorentz vxB force, which does not involve the time derivative dB/dt.
Bob S
A generator produces AC (alternating current) by using electromagnetism to convert mechanical energy into electrical energy. This is done through a process called electromagnetic induction, where a coil of wire is rotated in a magnetic field, causing the wire to cut through the magnetic lines of force and generate an alternating current.
The rotor is the rotating part of the generator that contains the electromagnets. As it rotates, it creates a changing magnetic field that induces a current in the stator, which is the stationary part of the generator that contains the coils of wire. The stator then outputs an alternating current.
The constant flow of AC current is produced by the rotation of the rotor and the design of the stator. The rotor and stator are designed so that the magnetic field changes direction every half rotation, resulting in a continuous alternating current output.
AC (alternating current) and DC (direct current) are two types of electrical currents. AC current changes direction periodically, while DC current flows in only one direction. AC current is typically used for long distance power transmission, while DC current is used for electronics and small devices.
The frequency of AC current is determined by the speed of the rotor's rotation. To maintain a steady frequency, the generator must maintain a constant rotational speed. This is usually achieved through a governor system that regulates the amount of fuel supplied to the generator's engine, keeping the speed consistent.