II. Дайте відповіді на запитання

1. What is often referred to as the "exciter" wire?

2. Modern automotive alternators have a voltage regulator built into them, haven’t they?

3. What do typical car alternators generate?

4. What does the stronger construction of alternators allow them to do?

5. What has only a 30 ampere alternator?

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III. Виходячи з відповідності речень до тексту, позначте їх +/-

1. Automotive alternators use a set of rectifiers to convert AC to DC.

2. Modern automotive alternators have a voltage regulator built into them.

3. In an alternator rated to produce 60 amperes of DC, the field current will be less than 2 amperes.

4. Some alternators will self-excite when the engine is revved to a certain speed.

5. Very large automotive alternators may produce 170 amperes.

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IV. Визначте тип термінів тексту стосовно їх будови

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V. Знайдіть приклади інтернаціональної лексики

ВАРІАНТ 18

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І. Прочитайте та виконайте повний письмовий переклад

Ignition system

The purpose of the ignition system is twofold: first to create a voltage high enough (20.000+) to arc cross the gap of a spark plug, thus creating a spark strong enough to ignite the air/fuel mixture for combustion; second to control the timing so that the spark occurs at the light lime and at the right cylinder.

The basic principle of the electrical spark ignition system has not changed for over 75 years. What has changed is the method by which the spark is created. The automobile has evolved from a mechanical system (distributor) to a solid state electronic system. Both systems control a low voltage primary circuit through an ignition coil which will induce a high voltage in the secondary circuit, which is then directed to the right spark plug at the right time.

The primary circuit consists of an ignition switch, ballast resistor, some type of off\on switch, (in the older cars a set of breaker points), which is usually inside n distributor, an ignition coil and the connecting wires. The purpose of the primary circuit is to allow low voltage from the battery, to pass through the ignition coil where the voltage is stepped up from 12 volts to as much as 40,000 volts.

Auto ignition coils are transformer devices in automobile ignition systems which produce the high voltage necessary to fire the sparkplugs of gasoline internal combustion engines.

The primary winding of the ignition coil is wound with a small number of turns and has a small resistance. Applying the battery to this coil causes a sizable DC current to flow (Ohm's law) even though it has a significant inductance which slows the increase of that current to its maximum value.

The secondary coil has a much larger number of turns and therefore acts as a step-up transformer. But instead of operating on AC voltages, this coil is designed lo produce a large voltage spike when the current in the primary coil is interrupted. Since the induced secondary voltage is proportional to the rate of change of the magnetic field through it, opening a switch quickly in the primary circuit lo drop the current to zero will generate a large voltage in the secondary coil according to Faraday’s Law. The large voltage causes a spark across the gap of the sparkplug to ignite the fuel mixture.

The current in the primary coil is caused to drop to zero quickly be the opening of a fast transistor switch. This causes the magnetic field in the primary coil to drop rapidly, generating a large voltage in the secondary coil. The generated voltage is proportional to the rate of change of the magnetic field according to Faraday’s law, and the amount of change is multiplied by the effect of the iron core in the secondary circuit.

The secondary circuit consists of the secondary windings of the ignition coil, which produces the high voltage needed to arc across the spark plug gap. This voltage is sent out the center coil lower, through a high tension wire to the distributor cap where a rotor distributes the spark through the distributor cap to the right spark plug at the right time.

Breaker points have not been used since the mid 70's, but many older cars still have them. The points are made up of a fixed contact point and a movable contact point. The movable point is spring loaded and rides on a 4,6 or 8 lobe cam (depending on the number of cylinders). The points are located inside a distributor. As the engine rotates, the camshaft turns the distributor, which then opens and closes the breaker points as many as 15,000 to 25.000 times a minute.

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