Основы английского языка для судовых электриков | страница 67

2. Impedance: The ratio of the r.m.s. /root mean square/ value of the voltage applied to an electric circuit, to the current flowing in the circuit.

3. Inductive reactance: Reactance in ac circuit caused by its inductance.

4. Inductance/inductance coil/reactance coil, choking coil: A piece of apparatus used in an electric circuit because of the fact that it possesses inductance.

5. Mutual inductance: It is the term used to describe the relationship that exists when a current change in one circuit induces an emf in another circuit. It depends upon the coefficient of coupling & the relative value of the two inductances. The coefficient of coupling is unity when all the flux lines of one coil cut across the turns of the other. In short, mutual inductance is the property of two circuits by virtue of which mutual induction occurs between them.

6. Variable inductor: An inductance coil whose self-inductance is continuously variable between wide limits.

39. / 5 мин./ Переведите словосочетания. Пользуйтесь словарем. Приведите несколько примеров с данными словосочетаниями.

То raise the potential of the positive-terminal end; to carry a current; to connect a light bulb to the source; to be at a higher potential; to apply a potential difference to the external circuit; the conventional direction of curent flow; to move through a conductor; the field exerts a force upon the charge; the charges are given energy through chemical action; to/dis/charge a battery.

40. / 5 мин./ Ознакомьтесь со смыслом следующих утверждений. Отметьте буквой R истинные, буквой W ложные утверждения.

1. The application of brushes & commutators eliminates many problems of maintenance, wear & dangerous sparking. 2. The induced emf voltage causes rotor current to flow. 3. Majority of motors for

marine installation are high in first cost & in maintenance cost, complicated & unreliable. 4. There is some difference in construction between a DC generator & a DC motor. 5. The starting characteristics define the operation of starting from the moment the motor begins running to the moment when steady-state operation is established. 6. To rectify the current in the external circuit, the machine is furnished with a special device called the conductor.

41. /2 мин./ Учитывая общий смысл и начальные буквы пропущенных слов, заполните пропуски.

Fig. 8. Electromagnetic relays, а/ With a clapper-type armature.Ь/ With a>pull-in armature.