Unlike a permanent magnet, an electromagnet can be turned on and off. One useful advantage of this: Place a metal bar inside the electromagnet, apply current through the electromagnet in one direction, and the magnetic field would move that bar one way -- reverse the current reverses the magnetic field and the bar would move the opposite way. You could use that effect and make an electronically controlled lock for a door.
A disadvantage of electromagnets is that they require electricity to become magnetized. If there is no electricity available, they are not useful to pick up items.
They are stronger and they can be turned on and off. It is also possible to vary and control exactly how strong the electromagnet is.
It doesn't require energy to maintain the magnetic field.
Using a magnet you can hover it over the cans.
The Advantages are that Hovercraft can fly, or more suitably, hover over water and land, can go over rough terrain and does not pollute as much as cars.
less expensive
The Pic Controller has many advantages over a 8051. The main advantage is the editing capabilities. Another advantage is the high resolution.
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A natural magnet is permanent - an electromagnet loses its power when it's switched off.
The advantage of an elecromagnet is that you can turn it on and off with a simple switch. So for example if you want to pick up a scrap car with a crane/electromagnet and move it, you can turn the electromagnet off when you want to release the car. You could not do the with a permanent magnet obviously.
A permanent magnet is always on; there isn't any way to turn it off. An electromagnet can be controlled; you can turn it on or off, or change the amount of magnetism by varying the current passing through the coils.
The electromagnet can be turned on and off depending on whether it's needed or not.
Electromagnets can have higher "domain currents" than permanent magnets, and have no non-aligned nor anti-aligned domains like permanent magnets tend to have (or get over time).
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.
But they are! You can find lifting magnets based on permanent magnets all over in machine shops.
The flux density of an electromagnet can be easily controlled. It's also easy and cheap to produce a large flux density with an electromagnet which is necessary for such large dc motors. Permanent magnets are generally expensive. For such a large motor,a very large permanent magnet will be needed for that motor which will not be ideal.AnswerElectromagnets are more powerful than temporary magnets, and -as pointed out above- their flux density can be controlled.
it can be made strongerit can be made in desired shape
The Neodymium Magnet is the strongest permanent magnet in the world. If you have two over a few centimeters they could cause a serious injury.
Many people are not aware of the fact that electric motors exist all around them. They are used in their car, washing machine, food processor, and so on. Even fewer people are aware of the way in which an electric motor actually works. Here are some of the basics. An electric motor is powered by the forces of electricity and magnetism. Magnets are used in order to create motion. Consider a simple magnet, with a north and south pole. The fact that a pole is attracted by its opposite and repulsed by the same is utilized in order to create the motion inside of an electric motor. The heart of the electric motor is the rotor, which is an electromagnet. An electromagnet consists of copper wiring that has been wound in a circle. When electricity moves in a circle, it creates a magnetic field. When electricity moves through the coil of wire, it becomes a magnet. When electricity is not passing through it, it is simply a coil of copper wiring. Inside an electric motor, there is at least one permanent magnet. When the electromagnet is activated, the north pole of the permanent magnet faces the north pole of the electromagnet. The permanent magnet is attached to an arm that can rotate around the electromagnet. Since the permanent magnet is repulsed by the north end of the electromagnet, it swings around to the other side. The direction of the electricity through the electromagnet is then reversed. This causes the north end of the electromagnet to become the south end. When this happens, the permanent magnet against swings over to the other side. This is the basic principle behind how all electric motors work. There are two basic types of electric motors: those that run on alternating current and those that run on direct current. A motor that runs on alternating current can take advantage of the fact that the direction of the electricity is constantly reversing in order to constantly reverse the polarity of the electromagnet and keep the electric motor running. In the case of direct current, a device known as a commutator is used in order to switch the direction of the current back and forth.
You have to take it out on a nice date first. Second, you have to pleasure the magnet for exactly 42 minutes. Third, you rub tons of ranch dressing all over the magnet on each side and keep it on there for 3-4 hours. These are the steps to make your electromagnet stronger.