Английский язык: Аннотирование и реферирование текста

259 the electromagnet flip. Because of the flip, the north pole of the elec- tromagnet is always above the axle so it can repel the field magnet's north pole and attract the field magnet's south pole. If you ever have the chance to take apart a small electric motor, you will find that it contains the same pieces described above: two small permanent magnets, a commutator, two brushes, and an electro- magnet made by winding wire around a piece of metal. Almost always, however, the rotor will have three poles rather than the two poles as shown in this article. There are two good reasons for a motor to have three poles: It causes the motor to have better dynamics. In a two-pole motor, if the electromagnet is at the balance point, perfectly horizontal be- tween the two poles of the field magnet when the motor starts, you can imagine the armature getting "stuck" there. That never happens in a three-pole motor. Each time the commutator hits the point where it flips the field in a two-pole motor, the commutator shorts out the battery (directly con- nects the positive and negative terminals) for a moment. This shorting wastes energy and drains the battery needlessly. A three-pole motor solves this problem as well. It is possible to have any number of poles, depending on the size of the motor and the specific application it is being used in. Motors Everywhere ! Look around your house and you will find that it is filled with electric motors. Here's an interesting experiment for you to try: Walk through your house and count all the motors you find. There are motors in: The fan over the stove and in the microwave oven, the blender, the refrigerator, the mixer, the vacuum cleaner, the fan, electric clocks and what not. In walking around your house, you can count plenty of electric motors hidden in all sorts of devices. Everything that moves uses an electric motor to accomplish its movement.