What are 3 advantages of AC motors over DC
- Equipment is much smaller for a given power output.
- Less maintenance required.
- Use of 3 phase gives a smooth rotating magnetic field for rotating machinery, with no rotor connections.
- Production of differing supplies is easily achieved with transformers.
What are the fundamental requirements of the L system?
- To generate and distribute electrical power from reactor during normal operation.
- To maintain electrical power supplies to the essential services when the reactor fails.
- To provide sufficient power to start up and shutdown the reactor
- To provide high integrity supplies for ship control, reactor instrumentation and reactor control.
- To provide an alternative means of propulsion on reactor scram.
What are the 2 reactor power states and their MCP combinations?
2F/2F (Fast speed ie Full Power) and 2S/2S (Slow Speed ie Half Power)
What are the major types of damage the NSRP can suffer from?
Mechanical
Chemical
Thermal
What is the function of the MSC? (Main static convertors)
These machines fulfil the requirement for no break supplies when the reactor fails or is shutdown ie no steam power run to TGs by power reversing.
What is the max power output for the Mgs AC and DC
The MSCs are rated at 700Kw DC and 650 Kw AC
What is the function of the Mgs?
- Generate DC for ships services (including battery floating)
- Generate AC for the ships service when both TGs are unavailable or carrying out a cold move
- Provide a changeover facility between a and b as required
- ‘Offload’ shore supply or the TGs onto main batteries as required
- Modes is voltage and frequency
What are the precautions before battery entry?
- Permission to be obtained from the SCOOW/OOD
- The battery is to be adequately ventilated and ventilation is maintained while personnel are working in the compartment-
- All metal objects are to be removed eg rings, watches etc.
- Any tools being used must be insulated
- Personnel working in the compartment are to wear overalls and rubber soled shoes.
- For safety reasons personnel must not enter unaccompanied.
Routines of a 25 week cycle
- Restricted charge as required
- Normal charge 3 per cycle
- Equalising charge 3 per cycle
- Conditioning discharge- one per cycle- this should be preceeded by one of the normal charges and followed by one of the equalising
- All round readings 2x per day
What are the functions of a diesel generator?
- Support AC and DC electrical services
- Charge the main battery
- Support the missile busbars
- Provide electrical power for diesel and electrical propulsion
- Provide electrical power to MSCs/ MGs to facilitate reactor start up independent of shore supply
What alarms does the teddington series 6 APP provide warnings, trips and alarms of?
Overspeed- tachogenerator Overspeed- Mechanical LO cooler outlet temperature LO inlet pressure Exhaust system 1st exhaust exhaust system 2nd exhaust Manual trip
What controls the SS procedure and where are they located?
Duty engineer in the manouvering room
What are the 2 line ups of ESS busbar intergrity?
Double MG/MSC Standby
Single MG/MSC Standby
Briefly describe the functions of a switchgear
- To allow power sources, busbar section and services to be switched in and out as required from central position ie manouvering room
- To open automatically trim conditions thereby:
- Protecting machines
- Protecting power cables
- Isolating faults - To open discrimitavley under trip conditions therby ensuring minimum disruption to electrical services.
What are the steps to close then open a BKR with a faulty retaining CCT?
To close the breaker:
a: Obtain permission from MEO
b: Check that the protection and interlock functions normally exercised by the closing coil/ closing coil contractor coil circuits are being satisfied
c: Set the retaining coil override to ON
d: Make the breaker in normal way from the ESP
To open the breaker:
a: Release the retaining coil override (breaker Opens)
b: set the control switch on the ESP to OFF
How is 24v derived and split through SM?
Nine Transformer rectifier units are fitted (4 FWD, 5 AFT) and supplied from the 440v 60hz essential busbars. Upon the loss of essential supplies these are supported via 24v battery.
Name the 5 panels in Man RM
Reactor services panel Main control desk Propulsion services panel Electrical services panel Environmental panel
What does the IRMU (Insulation resistance monitoring unit) monitor?
TGs MGs Shore Supply Secondary Propulsion Motor DC busbars DGs
