Т.Ю.Кущ, М.С.ВоловникАнглийский язык для судовых электромехаников. ENGLISH FOR MARINE ELECTRICAL ENGINEERS. 1986

Fill in the blanks in such a way that it makes sense.

1. Such deviations are sensed ... in the automatic equipment or on the set. (a) by means of each set; b) by means of transmitters; c) by non-critical alarms

2. An alarm may initiate ... of the starting procedure on the set concerned. (a) resetting of the alarm; b) shutting down; c) tripping, stopping and blocking

3. A critical alarm will stop the engine immediately, since ... (a) the starting procedure is blocked; b) the set is considered to be in danger of sustaining damage; c) such deviations are sensed by means of transmitters.

Now record your time and results.

Hometask: Ex. 36, 37.

The fifth class period

Review of “Automatic Control System for Ships Electrical Power Plants”.

38 15

Check your reading skills. See ex. 32, Section 1, Unit 2.

Part VI. Black-out Program

In the event of a black-out, the automatic equipment will start a certain number of diesel alternators. The set which is the first to acknowledge the frequency receives the instruction to switch onto the busbars. If the first set does not succeed in switching onto the busbars, it will be blocked and the next is allowed to make the attempt, etc. The reason for starting more than one diesel is primarily to prevent a fault on one set from delaying the clearing of the black-out condition, and in addition, the load often increases rapidly when the black-out condition has been cleared, and it is then advantageous to have at least one additional alternator about to be synchronized onto the busbars. The black-out condition is sensed by the automatic equipment by the fact that there is no voltage on the busbars and that all breakers are tripped. Both of these conditions must thus be satisfied.

Fill in the blanks in such a way that it makes sense.

1. The set ... receives the instruction to switch onto the busbars, (a) which is the first to acknowledge the frequency; b) which will be blocked; c) which delays the clearing of the black-out conditions.

2. If the first set does not succeed in switching onto the busbars,

(a) the automatic equipment will start a certain number of diesel alternators; b) it is then advantageous to have at least one additional alternator about to be synchronized onto the busbars; c) it will be blocked and the next is allowed to make the attempt, etc.

3. .. .is sensed by the automatic equipment by the fact that there is no voltage on the busbars and that all breakers are tripped, (a) delaying the clearing of the black-out condition; b) the black-out condition;

c) switching onto the busbars.

Now record your time and results. Compare them with ‘ previous ones.

39 15

Work in pairs. Dwell with your fellow-student on work with automatic control system for ships electrical power plants. Mind advantages and disadvantages (if any) of the system. Use ex. 17—19, 22, 24, 35—38.

40 35

Home exercise. Read the text. Write the number of logical units in each sentence. Draw a flow chart of programming of large loads. Make up as many questions on the text as you can and write a summary of it.

If a relatively large load is switched onto the network, a load surge will occur and this may cause overloading and in the worst case, tripping of the circuit breakers due to overcurrent. The risk of not taking this fact into account is illustrated by the starting current of a directly starting induction motor being 5—10 times the rated current.

For preventing such damages automatic control system is provided with unit, designed to control switching in such large loads.

The request for switching in a certain load is made in the form of a closing contact function. The load to be switched in is exceeded, switching in of the load is blocked until conditions render this possible, i. e. until a new diesel has been synchronized onto the busbars. If the power limit is not exceeded, clearance is given for immediate switching in of the load. When the load is switched in, the simulation is switched off, since the load will be metered by the ordinary equipment.

Hometask: Ex. 40.

6 —behkl; 7 —acdeghijknoprtuxyc'; 13—1. Поговорим, как мужчина с мужчиной, что, собственно, здесь произошло? 2. Богат, как Крез, и порочен, как сатана. 3. Все без исключения должны принять активное участие в этой работе. 4. Я далек от того, чтобы так думать. 5. Он считается чуть ли не светилом в этой области науки. 6. Боже мой, почему же я не могу этого сделать! 7. Он не от мира сего. 8. Об этом деле ему известно не меньше, чем кому бы то ни было. 9. Мой дедушка выбился в люди самостоятельно. 10. Я рано вставал и поздно ложился, во всем принимал участие, не уклонялся от опасности, и хоть раз в жизни вел себя, как подобает мужчине. 18 — Remote control system. 2 Safety system. 37 — lb, 2c, 3b; 38—la, 2c, 3b.

SECTION 4 (4-j-l+4)

The first class period

Review of “Automatic Control System for Ships Electrical Power Plants”.

15

Topical content: Automatic control of the shaft generators. 12

Text. Automatic Control of the Shaft Generators. Operation

1. When the order is issued for the main engine to operate at a constant speed corresponding to the correct frequency, and if the load on the dis-

tribution network is not in excess of the maximum permissible load on the shaft generator, and if no alarm is operative on the shaft generator, this combination of conditions is indicated on the control panel by the “shaft generator ready’’ lamp lighting up. The generator then rotates at the correct speed although without excitation, i. e. it generates no voltage.

2. If the change-over switch on the control panel is set to the “shaft generator on” position the generator will be excited and will generate a voltage. When about 85% of the normal voltage is attained, control of excitation shaft generator will be taken over by the voltage regulator in the switchgear.

3. The diesel-driven generator or generators supplying the distribution network are then synchronized to the shaft generator by the synchronizing unit in the shaft generator unit. When the generators are running in synchronism, the shaft generator breaker will receive a closure signal from the automatic control equipment.

4. When the shaft generator is in service and no alarm is operative, a shut-down signal will be applied to all diesel-driven generators. These generators will be unloaded, and the circuit breakers will then trip the generators from the distribution netw'ork. The diesel engines will then be stopped.

5. A synchronizing alarm will be initiated if the shaft generator is not synchronized to the network within about one minute. Other alarms in the equipment indicate high voltage, high frequency, low voltage and low frequency.

6. All alarms can be delayed by an adjustable period ranging between 1 second and 60 seconds. If a shaft generator alarm should become operative the number of diesel-driven units necessary to replace the shaft generator will then be started immediately and will be synchronized to the network. When a sufficient number of diesel-driven units are in service, the shaft generator will be unloaded and its circuit breaker will be tripped. If no diesel-driven unit is synchronized to the network after an adjustable time delay, the shaft generator breaker will trip and blackout will occur. The time delay for tripping the shaft generator circuit breaker can be set at any value between about 1 second and 60 seconds. The black-out will last only about 1 second, since the necessary number of diesel-driven units are already in service, although not synchronized to the network.