An alarm may initiate tripping, stopping and blocking of the starting procedure on the set concerned. Alarm indications are provided in the control panel, where resetting of the alarm can also take place. The alarms can be either non-critical (NCR) or critical (CR). A critical alarm will stop the engine automatically immediately, since the set is considered to be in danger of sustaining damage. Non-critical alarms cause shutting down in accordance with the ordinary shutting-down program and the starting procedure is blocked.
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.