2. The magnetism of electromagnet can be controlled by the strength of current or the number of turns of coil; You can also control the magnetic size by changing the resistance to control the current. Generally, the magnetic size of ordinary magnets will not change.
3. The magnetic pole of electromagnet can be controlled by changing the direction of current. That is, the strength of magnetism can be changed, the presence or absence of magnetism can be controlled, the direction of magnetic poles can be changed, and magnetism can disappear due to the disappearance of current. Ordinary magnets don't work.
Extended data:
Electromagnets are classified according to their uses:
1, traction electromagnet-mainly used for traction of mechanical devices, opening or closing various valves and performing automatic control tasks.
2. Lifting electromagnet-used as lifting equipment for lifting ferromagnetic materials such as steel ingot, iron ore, etc.
3. Brake electromagnet-mainly used for braking the motor to achieve the purpose of accurate parking.
4, the electromagnetic system of automatic electrical appliances ── such as electromagnetic relay and contactor electromagnetic system, automatic switch electromagnetic release and operating electromagnet, etc.
5. Electromagnets for other purposes ── such as electromagnetic sucker of grinder and electromagnetic vibrator.
References:
Baidu encyclopedia-electromagnet