The permanent magnet generator is a synchronous machine where the rotor windings has been replaced with permanent magnets. This eliminates the excitation loses in the rotor, which otherwise typically represent 20-30% of the total generator loses. The reduced losses also give a lower temperature rise in the generator, which means that a smaller and simpler cooling system can be used.
The temperature reduction in the rotor also reduces the temperature in the bearings, improving reliability by increasing the lifetime of the bearing and bearing grease.
A permanent magnet is a magnet that has been manufactured to "permanently" hold its magnetic field. Ferromagnetic material of a desired shape is heated above its Curie point, exposed to a large electromagnetic field, and cooled slowly while being held in that field. This allows the magnetic domains in the material to align themselves with the field of the electromagnet. Further, when the material cools below its Curie point, the magnetic domains will remain in the position they are in when the electromagnet is shut off. The magnet is now a permanent magnet; the magnet "holds" the magnetic field "imprinted" on it.
That refers to a machine that uses a permanent magnet. A permanent magnet - as opposed to an electromagnet - is one whose magnetism doesn't depend on a normal electric current flowing through it.
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It means that it doesn't quickly lose its magnetism. This is in contrast to an electromagnet, which loses most of its magnetism as soon as the current is turned off.
No, it's a permanent magnet. It consists of an iron oxide, and iron is a permanent magnet.
no it is not . a temporary magnet is used instead. If you use a permanent magnet, the doorbell will keep on ringing
Yes, as it is a magnet that will remain for a long time that makes it permanent. : ) x
ferromagnetic
heating the magnet past the Curie point
By definition an electromagnet is only working when it has a supply of electricity, a Permanent Magnet is always a magnet
A. Compasses typically use a permanent magnet.
No, it's a permanent magnet. It consists of an iron oxide, and iron is a permanent magnet.
Yes, it is a permanent magnet.
No, it's a permanent magnet. It consists of an iron oxide, and iron is a permanent magnet.
Permanent magnets do not lose their magnetic ability. Temporary magnets, however, gain magnetic properties when they are touched or moved by a permanent magnet. The properties of a temporary magnet dissipates over time after the permanent magnet is removed.
PermanentThere is no source of current in a compass, therefore the magnet is a permanent magnet.
yes
An example of a permanent magnet would be the Earth. The Earth is one giant magnet with opposite poles.
Perminant magnet
You cannot magnetize a permanent magnet because it is already magnetized.
It is a permanent magnet. Electromagnets(as the name suggests) requires an electric source to become a magnet, when the power source is turned off it will not function as a magnet.