Any permanent magnet can just be magnetized, having arranged it in a certain way in external magnetic field. Strengthening of electromagnets happens due to increase in current of a winding or quantity of its rounds.
It is required to you
- - set of permanent magnets;
- - glue;
- - current source;
- - the isolated wire.
Instruction
1. Take a permanent magnet. Arrange it in external magnetic field which is stronger than magnetic field of the magnet. It can be created other, more powerful permanent magnet, and it is possible an electromagnet. Continue to keep a magnet in this field some time and its magnetic properties will improve. For each magnet its strengthening depends on a set of factors therefore the effectiveness of such way cannot be predicted.
2. To strengthen a permanent magnet, unite it with other magnets, in this case the field will amplify in proportion to quantity of magnets. Connect magnets with each other so that the poles of the same name were oriented equally. As at the same time they will make a start therefore they need to be stuck together.
3. At achievement of some temperature the magnetic properties of a permanent magnet disappear. This point is called Curie's point. But cooling of a magnet up to the temperature much below than Curie's point does not increase his force as this transition is phase, that is spasmodic.
4. The electromagnet represents the core from electrotechnical steel with the isolated wire which is reeled up on it. Increase its magnetic force in two ways. The first – increase the current given on a winding. In this case magnetic induction of the field will increase in proportion to increase in current in a magnet winding. But if current in a winding exceeds value of short circuit current, it will fuse, then the electromagnet will fail. Therefore it is necessary to increase the current given on an electromagnet very carefully. Increase in current is carried out by means of increase in EMF of a source of current.
5. If it is not enough, strengthen an electromagnet in a different way – increase quantity of rounds of a winding, without increasing its length. For this purpose impose the second row of a wire and if that is necessary and the third. Magnetic induction of the field will increase in proportion to increase in quantity of rounds on the electromagnet coil.