MEO Class 4 Oral Questions MMD Function 5 EECEOL(Electrical) | MMD

MEO Class 4 Oral Questions MMD Function 5 EECEOL(Electrical) | MMD

Have you applied for MEO Class 4 Function 5 i.e EECEOL, generally called Electrical? If yes, then you’re in right place to start your preparation.

The full form of EECEOL is Electrical, Electronics, and Control Engineering at Operational Level. Function 5 is considered a bit easier function in MEO Class 4 Exam as compared to the other functions. Because of the limited syllabus.

In this article, I’ll share the most frequently asked Oral questions in MMDs on Function  5. The more questions you practice, the more confident you’ll become for orals. So practice as many questions as possible.

Most people hate reading long articles. So, to make it easy for you, I have divided the entire set into different sections. Each section includes 50 questions.

Related Read: You can practice/download MEO Class 4 Written Questions & Answers from here.

Let’s get started.

Function 5 EECEOL Section 1

Function 5 EECEOL Section 1

  1. Rectifier? How does it work? Example?
  2. Transformer? Working?
  3. Megger testing
  4. How to detect earth fault?
  5. Generator trips
  6. Alternator trips
  7. Describe preferential trip
  8. Electric principle of welding
  9. How emergency generator does comes on load when the main power fails
  10. Synchroscope function
  11. Power distribution system with diagram
  12. Why is a Megger used for insulation test and not a multimeter? (With a megger, a voltage of not less than 500 volts DC is used for testing the insulation resistance of windings. With a multi-meter, the voltage used is not more than 3-volts DC. Megger uses high impedance testing and is, therefore, more accurate than a multimeter)
  13. How do you test reverse power trips?
    • (When two generators are running in parallel and one generator can carry the load, reverse power trip can be tested by load shifting using governor control. When the load has shifted sufficiently and the offloaded generator is carrying a small
      percentage of load, its breaker trips and fuel supply to its prime mover cuts off. This means the reverse power relay has operated. The relay can be tested by simulation (using the test push button on the relay) to see if it initiates a trip signal. Simulation and actual both can be used to test. In actual change controls to manual. Reduce load one gen and increase on the other. Reverse power will trip at – 10% of rated power.)
  14. Why do we close the switch at 11 o’clock and not at 12 o’clock?
    • (When the synchroscope is approaching 12 o’clock the “slip” (differential) between the sine waves is approaching minimum (slip is zero when the synchroscope is at 12 o’clock) and the voltage differential between the phases is minimal (it’s zero when the synchroscope is at 12 o’clock). Due to the time taken to close the synchronoscope switch, it is generally done at 11 o’clock. Due to the small delay to close, by doing at 11 o’clock, we are achieving closing close to 12 o’clock.)
  15. How is the speed of a DC motor varied?
    • To vary the speed of a DC motor we need a constant voltage power supply with a series POT resistor of a higher watt rating. A Pulse Width Modulator (PWM) can be used.
  16.  What does three-phase current mean?
    • Three current sinusoidal waveforms equal in magnitude but with a phase shift of 120 degrees.
  17.  After a blackout the emergency generator comes on; On restoring the main supply we are closing the circuit breaker of the main generator without bothering about synchronizing. How is this possible?
    • There is a power link connection breaker between the main generator and the emergency generator. During the blackout, this breaker trips. The emergency generator starts and its breaker closes and feeds only the emergency loads. During restoration, the main generator is started again and its breaker is closed. As the link breaker is still open, there is no paralleling between the main and emergency generator.
  18. How is the speed of a 3-phase induction motor varied?
    • The speed of a normal 3-phase induction motor is a function of the frequency of the supply voltage. Changing the speed of such a motor hence requires building a 3-phase power frequency convertor. This can be realized by using power MOSFETs (or IGBTs) capable of handling high voltages and fast switching speeds.
  19. What safety precautions need to be taken during maintenance on batteries?
    • The room needs to be ventilated to prevent explosions due to gases generated by the battery. Protective clothing, gloves, and eye protection should be used to prevent acid splash over. No flames or ignition sources should be brought near batteries. Never short both positive and negative terminals as this will cause a short circuit and high energy flashover. When disconnecting batteries, always disconnect negative terminals first and vice versa when reconnecting.
  20. Explain the condition for Paralleling of Alternators?
    • The following conditions must be fulfilled for proper synchronizing of alternators.
    • The terminal voltage of the incoming machine must be approximately equal to bus-bar voltage.
    • The frequency of the incoming machine must be equal to that of the bus bar.
    • In the case of 3-phase alternators, an additional requirement is that the phase sequence of the incoming machine voltages must be the same as that of the bus bars.
  21. If you get an earth fault alarm what will you do?
    • The fault can be investigated by first identifying areas of the ship that have a high chance of earth fault (for example deck lighting or pantry equipment) and then switching off their supplies one at a time to see if the alarm is gone. When a particular load clears the alarm, we know that that circuit is having an earth fault and we can go and repair it.
  22. How does current flow during welding?
    • The current flows through the electrode and to the clamp. That’s how it flows in MIG, stick, flux-cored. On Tig, the electricity flows through the electrode also except that now that’s the only function of it, the rod is held in your hand and electrode in the other.
  23. What is an AVO meter?
    • The Avometer was a British brand of multimeter, latterly owned by Megger. It is often called simply an AVO and derives its name from the first letter of the words amperes, volts, ohms
  24.  What limits the electrical load?
    • The available power is fixed and the voltage is fixed, so the setting of the breaker or fuse is the normal current of the load. If the load exceeds the rated current, then the breaker or fuse will operate and limit the load.
  25.  What is the meaning of saying I and V are in phase?
    • The angle between the I and V waveforms is zero which means the load is purely resistive.
  26.  Where is it used?
    • Synchronous motors find applications in all industrial applications where constant speed is necessary. Improving the power factor as Synchronous condensers. Electrical power plants almost always use synchronous generators because it is important to keep the
      frequency constant at which the generator is connected. Low power applications include positioning machines, where high precision is required, and robot actuators.
  27.  What are the differences between synchronous and induction motors?*
    • Synchronous motor: Constant speed on all loads, can be operated on a wide range of power factors, not self-starting, requires dc excitation.
      Induction Motor: Speed varies with load, operates on lagging power factor, self-starting, no dc excitation required.
  28.  What are the safety precautions when working on electrical equipment?
    • Switch off the power, wear proper protective clothing, safety shoes, Notice board: Do not switch on – Men at work, stand on a rubber mat, remove metal rings, watch bracelets, use properly insulated tools, check power supply with a voltmeter and double-check the
      voltmeter with known power supply, keep one person stand-by with proper safety gears, inform authority and get a proper work permit. In case of electrical shock, give proper first aid, check heartbeat and pulse.
  29.  Why is special lighting used in battery rooms?
    • Spark proof lighting is used as explosive gases may be generated during battery charging and so there should be no sparks in the room.
  30. Where is a slip ring used and where is a commutator used?
    • Slip rings are commonly found in slip ring motors, electrical generators for alternating current systems, and alternators. They can be used on any rotating object to transfer power.
    • A commutator is a common feature of direct current rotating machines. By reversing the current direction in the moving coil of a motor’s armature, a steady rotating force (torque) is produced.
  31.  When does Reverse power flow?
    • The situation of a generator is feeding a system through switchgear having several generators connected in parallel with this generator. The flow of current, when the system is running normally, is from the generators to the switchgear. If one generator experiences
      problems and its terminal voltage fall below the system voltage, the generator will act as a motor, just as a motor can act as a generator, and current will flow from the switchgear to the generator. This is reverse power. The effects can range from minor to extreme in the event of a complete mechanical failure of the generator which fails.
  32.  What protection is provided against this?
    • Single phasing can be identified by special protective relays which can identify and isolate the connected loads. Smaller motors rely on overcurrent and negative phase sequence relays. Motor protection relays for larger motors come readily fitted with protection against single phasing.
  33.  What is special about Steering gear Overload safety?
    • Short Circuit protection and appropriate single-phase protection are fitted. In addition instead of overcurrent protection, an Overload alarm is fitted set to operate at not less than twice the normal running current.
  34.  What is the RMS value?
    • Root mean square value is the peak value divided by the square root of 2
  35.  How is the protection against reverse power given?
    • Reverse power protection is used for anti-motoring. This function is used for the protection of the prime mover, not the generator. It can cut off the fuel supply and stop the prime mover.
  36.  Where does reactive power go?
    • Reactive power is not ‘lost’. It is delivered to the motor where it sustains the electric field that enables the motor to convert the real power (electrical) into mechanical torque.
  37.  What is the meaning of a preferential trip? Why is it provided?
    • A preferential trip is a kind of electrical arrangement on the ship which is designed to disconnect the non-essential circuit i.e. non-essential load from the main bus bar in case of partial failure or overload of the main supply. It lets the critical loads run (like steering gear) and trips the non-essential loads (like AC and galley) and is a safety
  38. What is the meaning of the power factor?
    • Power factor is the cosine of the angle between voltage and current waveform.
  39.  How can it be improved?
    • Power factor improvement capacitor banks are used if the loads are mainly resistive.
  40.  What is the benefit of improving power factor?
    • Power factor close to 1 means for the same real power in kW, the load current is less, and hence the I2R losses are less. The system efficiency is higher as the losses are lower. Improved voltage regulation is achieved.
  41.  For a given line voltage, four heating coils will produce maximum heat when connected in- Parallel
  42. If a motor is wound star and you want to change to delta what should you do?
    • Open the terminal connection box. Remove the shorting link connecting the common connection (star) points of A2, B2, and C2. With the 3 phase windings marked A1A2, B1B2, C1C2, connect A2 to B1, B2 to C1, and C2 to A1.
  43.  What is the voltage used for ignition in boilers/incinerators etc.?
    • Normally 10,000V (10kV) – incinerator and around 19k in boilers
  44.  What can be possible reasons for a motor failing to start?
    • No power, Fuse blown, Overload trip, contactor coil burnt, Contactors contacts bad, control circuit relay faulty, stop switch open circuit and start switch does not operate, hold on contact does not make and motor burnt.
  45.  Explain what happens if a DC motor is fed with an AC supply?
    • The motor will run at low speed, sparking at brushes, heat due to eddy current will finally burn the motor.
  46. Why is 440 V used for motors and 110/220 V used for lighting?
    • Motor load currents are large. Motors are 3-phase loads. A higher 440V voltage means lesser current for the same power and hence losses and size of cable wires are lower. Lighting is single-phase loads and its load currents are small, hence lower voltage means
      less insulation in the cable wires.
  47. How to test emergency generator widout switching off main supply
    • Many methods
      1. Simulation switch
      2. Tiebreaker on ESB to be switched off
      3. Tiebreaker on MSB switched off.
      Anyone can be used
  48. Compare between lead-acid and nickel-cadmium batteries?
    • Lead-acid: Dilute H2SO4, spongy and PbSO2, low efficiency, 2 volt per cell, less strong, requires more maintenance, less efficient wrt temperature, discharges fast, low cost, the problem of sulfation.
    • NiCd: KOH, Ni & Cd, high efficiency, 1.2V per cell, robust, less maintenance, more efficient wrt temp difference, retains the charge for longer periods, expensive, no sulfation.
  49. Why are motor ratings given in KW and that of alternator and transformer given in KVA?
    • kW is the output mechanical power of a motor and is expressed in kW.
    • kVA is the net (apparent) power input to the transformer. This input power is the output + losses.
      kW = kVA x system power factor
  50. What is a self-monitoring alarm circuit?
    • It self monitors the health of the alarm circuit. That is, it senses whether the power supply to the alarm circuit is healthy and all the relays and contacts are functioning normally.

Function 5 EECEOL Section 2

Marine Electrical Questions and answers

  1. What is Under-voltage protection?
    • It prevents closure of the breaker by mistake or the generator that is coming on load during parallel operation. It also provides protection against loss of voltage while machinery is connected to the switchboard.
  2. Why is it different from that for welding?
    • It is higher as the ignition requires a breakdown of the air gap for the spark to
      occur. The air breaks down at this high voltage of 10kV. Therefore, it is higher than the normal welding voltage.
  3. How does the emergency generator start automatically?
    • It is activated by an under-voltage relay. When there is a blackout, the under-voltage relay senses the loss of voltage and starts up the emergency generator. Similarly, when the power is restored, the relay stops the emergency generator.
  4. What is the purpose of the earth fault indication on the switchboard?
    • It detects and indicates phase-to-earth faults on a circuit.
  5. There is something done to the bearing pedestal of an alternator, what is it?
    • Insulation pads made from nylon are fitted under each pedestal bearing and the bearing holding down bolts are similarly insulated. MAGNETIC INTERPOLES producing opposite ampere-turns fitted which minimizes the effect of stray magnetic fields causing reduced
      emf in the shaft.
  6. What is a diode?
    • In electronics, a diode is a two-terminal electronic component with asymmetric transfer characteristic, with low (ideally zero) resistance to current flow in one direction, and high (ideally infinite) resistance in the other. A semiconductor diode, the most common
      type today is a crystalline piece of semiconductor material with a PN junction connected to two electrical terminals
  7. Sometimes, when you change the running direction of an E/R blower (from supply to exhaust) it trips. Why?
    • If the flaps of the blower are not set or opened properly or the filters are clogged, the air supply is affected and the blower may be overloaded causing it to trip.
  8. If all your air bottles are at low pressure and there is a blackout how do you start the generators?
    • If the main air bottles are empty, the emergency air bottle can be used to start the main generator. If even the emergency air bottle is empty, then it can be filled by running an emergency air compressor (powered by an emergency generator). Once the emergency air bottle is filled, this air can be used to start the main generator.
  9. What is the function of a fuse?
    • Fuse places a limit on the amount of current that can be drawn by an electric circuit by opening (blowing or melting) when the current exceeds a preset limit. This protects the circuit and the surroundings from fire or damage in the case of an overload or
      short circuit.
  10. What is the regular maintenance done on batteries?
    • Every week the cell voltage is checked. The specific gravity is monitored using the battery hydrometer. The terminals are lubricated to prevent corrosion. Sometimes load tests are done on the batteries.
  11. Purpose of AVR During KVAr loading, voltages of alternators fall which can be
    gained by AVR, which increases the excitation until the voltage is back
    to normal.
  12. How does this cause a rotation to change?
    • Due to the change in phase sequence, the rotating magnetic field changes direction and the rotor rotates in the opposite direction.
  13. How is protection provided for OL and SC?
    • Damage from short circuits and overloads can be reduced or prevented by employing fuses, circuit breakers, or other overload protection, which disconnect the power in reaction to excessive current. The tripping time is much less (in milliseconds) for short
      circuit due to very high currents but can higher (a few seconds) due to currents say 1.1 to 1.5 times the normal current.
  14. What is a current transformer and voltage transformer?
    • Current transformers used for sensing load currents and as inputs to indicating instruments. Voltage transformers used for step-up/step-down voltages.
  15. What is a relay? How is it different from a magnetic contactor?
    • A contactor is a heavy-duty switch whereas the relay is a light-duty switch.
    • Relays can be as simple as 12 V DC solenoids with 12 V, 0.5 A-rated contacts. They are used to detect faults on the power system and signal a local or remote switching device (breaker) to trip the circuit.
  16. What is the color code of resistors, Please explain?
    • Colors to denote value. In four-band color-coding, the first band indicates the first digit, the second band: the second digit, and the third band: the number of zeroes.
    • The values are as given below:
      Black : 0, Brown : 1, Red : 2, Orange : 3, Yellow : 4, Blue : 5, Green : 6, Violet : 7, Grey : 8, White : 9.
  17. What are the safeties on MSB?
    • Circuit breakers, fuses, and over-current relays are used. The panels are dead front panel, that is, we cannot open the panel for maintenance until we switch off the power to the panel by the circuit breaker.
  18. What is capacitance?
    • Capacitance is the ability of a body to store an electrical charge. Anybody or structure that is capable of being charged, either with static electricity or by an electric current exhibits capacitance. C = Q/V, where Q is the charge and V, is the voltage
  19. Even though the main engine runs at varying speeds, how does the alternator maintain constant

    • By use of thyristor controlled frequency (rpm) converters.
  20. How is this voltage achieved?
    • By connecting 12 cells in series. 12 x 2 V = 24 V is total battery bank voltage.
  21. How is the direction of rotation varied? By changing the phase sequence (from say R-Y-B to R-B-Y)
  22. What is the harm if reverse power flows?
    • Assume that the generator normally produces an amount of power equal to P and that when operating as a motor, it will absorb a similar amount, P. Therefore, the net effect on the grid will be the same as if it experienced a step increase in load equal to 2P. Depending on the size of the grid and the strength of the remaining generation, a step increase of 2P could result in a significant frequency change on the grid. There could be prime mover damage in some instances (especially steam turbines).
  23. If you press the ACB Close button on an idle generator what will happen?
    • Normally, the breaker won’t close until you synchronize, so even if you press the breaker close, it will not close. The breaker has under-voltage protection which will not let you close it.
  24. Apart from renewing bearings is there any reason for opening up motors for maintenance?
    • Insulation checks and renewal (example using insulation spray-on stator winding insulation)
  25. What is the meaning of overload?
    • An overload is a current over and above the normal load current (over the load).
      In other words greater than the original design current. This can be a momentary overload such as the starting current for a motor which is usually ignored or it can be a sustained overload such as plugging in too many appliances at once or a motor that has faulty
      bearings or gets jammed
  26. What is an induction motor?
    • An induction motor is an alternating current motor in which the primary winding on one member (usually the stator) is connected to the power source and a secondary winding or a squirrel-cage secondary winding on the other member (usually the rotor) carries
      the induced current.
  27. What is the meaning of excitation in an alternator?
    • An electric generator or electric motor consists of a rotor rotating in a magnetic field. The magnetic field may be produced by permanent magnets or by field coils. In the case of a machine with field coils, a current must flow in the coils to generate the field, otherwise, no power is transferred to or from the rotor. The process of generating a magnetic field by means of an electric current is called excitation.
  28. Permanent magnets are generally made of- Alnico alloys
  29. What is the full form of ACB?
    • Air circuit breaker. It is normally used at 400V and higher current applications (generator breakers).
  30. What is the meaning of ACB, MCCB, NFB?
    • Air circuit breaker for 400V higher current ratings.
    • Moulded case circuit breaker for 400V medium current ratings.
    • No Fuse Breaker – 75 A capacity
  31. What is the synchronous condenser?
    •  Synchronous condenser is a device identical to a synchronous motor, whose shaft is not connected to anything but spins freely. Its purpose is not to convert electric power to mechanical power or vice versa, but to adjust conditions on the electric power transmission grid. Its field is controlled by a voltage regulator to either generate or absorb reactive power as needed to adjust the grid’s voltage or to improve the power factor.
  32. What is the meaning of a short circuit?
    1. A short circuit occurs when conductors are connected (shorted) together by a fault. This is normally phase to phase fault due to failure of insulation by something cutting the wires, fires, etc.
  33. How is the direction varied?
    • A general-purpose DC motor can be reversed by changing the polarity of either the armature or the field but not both.
  34. What is a magnetic contactor? Where is it used?
    • A contactor is an electrically controlled switch used for switching a power circuit, similar to a relay except with higher current ratings. Contactors are used to control electric motors, lighting, heating, capacitor banks, and other electrical loads.
  35. What does the different position of the synchroscope needle mean; what is the difference between 6 o clock and 12 clocks?
    • 6 o’clock means that out of synchronization. We cannot parallel the incoming generator. 12 o’clock means the perfect synchronized condition (voltage, frequency, and phase sequence match).
  36. What is the voltage used in a meggar? 500V DC.
  37. What is the full battery voltage? 24 V DC.
  38. What is the voltage available from each cell in a lead-acid battery? 2 V DC.
  39. What is the specific gravity of electrolytes used in lead-acid batteries? 1280 at full charge and 1180 at discharge.
  40. What is the best value possible? 1 is the best value possible. That is possible with a purely resistive load.
  41. Out at sea, if there is a blackout during your watch, what action will you take?
  42. Why generally we use an induction motor on board, not the synchronous motor?
    • Easy to make. Serves our purpose on board. Easy to operate. Singly excited ac supply is more than sufficient to start and rotate the motor. Induction motors are Used where speed control is not a priority at all but continuous running, easy start motors are needed.
  43. What is the usual value you see onboard? 0.8
  44. Can reverse power trips occur with one generator running? If yes, how? If no, why?
  45. Short circuit and Earth fault: Define
  46. Star-Delta starter: No diagram jus explain why used on-board
  47. What is KVA?
  48. What is meant by phase in AC?
  49. Why is DC not much in use now?
  50. Where are you likely to see DC used?

Function 5 EECEOL Section 3

Marine Electro Technology Questions and Answers

  1. What is the function of commutator in DC motor?
  2. What is Fleming’s law?
  3. What are the emergency generator requirements as per SOLAS? How will you confirm that the emergency generator has come on load within 45 seconds?
  4. How to carry out insulation resistance test?
  5. MSB safeties?
  6. AVR with diagram
  7. Brushless gen with diagram
  8. Reverse power trip with diagram
  9. Limiting value of IR at which motor will keep on running with insulation leaking
  10. Megger testing, how to connect probes
  11. How current moves in a conductor
  12. What is the difference between AC & DC?
  13. Compare AC & DC with stresses.
  14. What will you do if there is low insulation when you start a motor. How will you correct it
  15. Overhaul of motor
  16. Alarm or trips on the steering gear motor.
  17. Maintenance on Alternator
  18. Safeties on MSB
  19. Reverse power trip & testing
  20. Power factor definition. How will u calculate it?
  21. Wheat stone bridge principle. How it’s balanced? Relation between R1 R2 R3 R4
  22. Megger why used? How to test its working? Types of megger? How does it measure insulation when you are setting a voltage range on it? How will the dynamo work on non-battery type?
  23. Type of transformer in welding machine?
  24. What is the function of fuses?
  25. Different kind of fuses
  26. Motor protection
  27. Open circuit fault
  28. Earth circuit fault
  29. Reverse power trip
  30. Generator safeties
  31. Protection in motors for short circuit
  32. Safeties on MSB?
  33. Earth fault indication alarms activated. What step you will take?
  34. Blackout occurs on your ship. What will be your action?
  35. Paralleling of Alternator: Conditions and Manual procedure
  36. What is single phasing?
  37. Paralleling of generators? (mention all the 4 conditions)
  38. Preferential trip
  39. Power factor
  40. Trickle charge
  41. Actual electrical parameters on-board your ship
  42. What is IP number? What the two digits of it indicate? What was the IP number for motor in the engine room, and for MSB?
  43. What is Insulation resistance? What is the temperature value for class F insulation?
  44. What is earth fault? Why it occurs? Is there any system to monitor continuously? What is the minimum value of it is allowed?
  45. What all ratings of motor are given on its nameplate?
  46. What is IP for MSB?
  47. IP and significance for motor, what was IP of E/R motors in your ship?
  48. Induction motor principle.
  49. Starters, why it is required?
  50. Star delta starter diagram and explanation

Function 5 EECEOL Section 4

Marine Electro Technology Questions and answers

  1. AVR diagram and working. Why it is used?
  2. Reverse power trip
  3. Preferential trip, what are essential and non-essential loads?
  4. Zener diodes.
  5. Intrinsic circuit. Where it is used?
  6. Explosion-proof motor and where it is used.
  7. Safeties on an overhead crane.
  8. Electrical hazards.
  9. Fire class motors.
  10. Overhead crane limit switch value.
  11. Star circuit. Power calculation. Power factor. What is phase angle?
  12. Safety of ESB.
  13. Emergency generator Safety.
  14. Types of batteries? Sp Gr? Voltage? Reaction? How will you know the battery fully charged? What battery onboard? Its rating? What is voltage for charging? (26V) Battery maintenance? Hydrometer? Principle of Hydrometer?
  15. What all types of power supply onboard? Why 440V in ER and 220/110V in accommodation? Why not opposite?
  16. Types of the motor on board? Principle? Synchronous vs induction motor? Where synchronous motor used?
  17. How to parallel generator? How do you know the incoming generator in phase? Synchroscope diagram?
  18. Fleming left and right-hand rules? Lenz’s law?
  19. Under voltage trip diagram
  20. If two generators are sharing an equal load but amps are different
  21. How is electricity produced? From where it is tapped?
  22. General electrical safeties?
  23. What general safeties you will find in a starter box or near the starter box?
  24. ESB safeties 440v earth fault alarm
  25. 220v earth fault alarm
  26. Battery charging failure alarm
  27. IR alarm
  28. How is earthing given to the ship? What is NER? What purpose? If not given what would happen?
  29. How is earthing given on the shore?
  30. Starter maintenance?
  31. How to test insulation resistance? On the whole what should be the value for the entire ship how much it should be? How will you check it for the motor?
  32. ESB 440v supplied to?
  33. Emergency generator: means of starting
  34. Paralleling,
  35. Synchroscope diagram
  36. Transformer principle
  37. MSB block diagram
  38. MSB safeties: Physical and Electrical
  39. Emergency generator starting requirements, procedure
  40. Power management system block diagram and working
  41. Induction motor working diagram and principle
  42. Battery maintenance
  43. Battery Room Safeties
  44. Draw explosimeter
  45. What are safeties in E/R overhead crane? What is a fail set mechanism?
  46. If electrical cargo p/p is there on your ship and you are discharging a cargo of Sp. Gr.1. Motor current is 400A, you change over cargo tank and a new tank is of cargo whose sp. gr is 1.8. What will happen?
  47. What is intrinsically safe equipment?
  48. How do you measure SG of battery acid? Then what is Hygrometer? What is the working principle of Hydrometer & Hygrometer? (Hydrometer for SG, Hygrometer for humidity In the air)
  49. E/R crane safeties
  50. E/R crane motor safeties. Fail-safe of brake & Brake Diagram.

Function 5 EECEOL Section 5

Marine Electrical Questions and answers

  1. Alternator routines
  2. Your generator working ok, but the alternator not producing proper voltage?
  3. Motor maintenance (Megger IR check etc)
  4. Motor safeties
  5. Motor speed control
  6. Difference between synchronous motor and induction motor
  7. Synchronous motor-  Where used in ER
  8. Synchronizing how done dark lamp etc circuit diagram
  9. MSB safeties
  10. What happens if the generator overloads?
  11. Preferential trip in detail
  12.  Emergency supply goes to where
  13. Power factor in detail
  14. How to calculate onboard power factor?
  15. When we get power factor=1?
  16. Ships Power Supply system
  17. Why Starters fitted- the function of DOL Starter?
  18. What is an Isolation Transformer?
  19. Principle of Transformers- what happens to current and voltage during transformation?
  20. Draw and explain Brushless Generator. Residual Magnetism etc
  21. Navigation Light Panel.
  22. Motor Safeties.
  23. Single Phasing, How will you come to know which phase has gone, how will you test?
  24. Megger working. How to test IR resistance. Why you can’t use a multimeter for the same??
  25. How to use megger, multimeter and tong meter?
  26. Safeties of MSB, why 0.6 m gap is given behind
  27. Battery checks
  28. Procedure for entering battery room
  29. Insulation resistance, minimum acceptable value
  30. Open circuit fault
  31. What are the ESB safeties as per SOLAS
  32. What is MCB and what all trips are provided on MCB
  33. What type of fuses is used in ER? If the HRC fuse is blown off what test will u carry out?
  34. What is a reverse power trip and how will u carry out the test to check the trip is working?
  35. How to check reverse power trip? Prime mover will be running or not? Then take the gene again on load.
  36. Types of fuses? Explain semi-enclosed? Is semi-enclosed present in the ship?
  37. Power factor.
  38. Types of fuses in the engine room, how to test a ceramic fuse, what position will you keep the knob of the multimeter when testing the fuse? (on continuity or resistance)
  39. What type of crane on deck?
  40. MCB trips,
  41. How to check that a 3 phase motor is star or delta connected just by looking at the terminals. Draw the arrangement.
  43. Types of induction motors
  44. Lead-acid batteries its safety battery room ventilation
  45. Welding circuit
  46. Single earth fault, short circuit fault
  47. Short circuit fault safeties
  48. Navigation lights – AC / DC?
  49. DC motor on board?
  50. Difference b\w AC and DC motor?

Function 5 EECEOL Section 6

Function 5 EECEOL Oral Questions and answers

  1. What is a semiconductor?
  2. What is doping?
  3. What happens to insulation when the temperature rises?
  4. What are Superconductors?
  5. What happens to the resistance of conductors when the temperature rises?
  6. What is “slip”?
  7. What is a synchronous motor?
  8. How do you use a multimeter?
  9. How do you check continuity?
  10. What do we use for welding on ships? AC or DC?
  11. What is the voltage?
  12. Does current flow through-hull during welding?
  13. If so why don’t you get a shock?
  14. What is a safe voltage to prevent shock?
  15. What is the meaning of earthing in a ship?
  16. What is the meaning of Star winding/ Delta winding?
  17. Is the ship’s alternator Star wound or Delta wound?
  18. Can you draw a DOL starter circuit?
  19. What is the normal setting of overload relays?
  20. How does a thermal overload relay work?
  21. What is single phasing?
  22. How can it happen?
  23. What is the harm caused by this?
  24. Why is it necessary that incoming alternator frequency is more than bus bar?
  25. What are the dark lamp and bright lamp methods for synchronizing? How is the connection made?
  26. Why is this reverse power used instead of reverse current in alternators?
  27. Is the field current in an alternator AC or DC?
  28. Is the field rotating or stationary?
  29. How is it supplied?
  30. What is a brushless alternator?
  31. How is the excitation achieved in this?
  32. What is the meaning of residual magnetism?
  33. What is a Zener diode?
  34. What is a thyristor? What is an SCR?
  35. How does an inverter work?
  36. How does a tube light work?
  37. What is the function of the choke?
  38. What is the difference between neutral and earth?
  39. If the AVR, is defective when additional loads come on will the generator be able to take it?
  40. How do you test reverse power trip, high current trip, preferential trip?
  41. Why is a capacitor used in single-phase motors, fluorescent tube lights, and electronic circuits?
  42. while welding onboard a ship the current passes through-hull, then why people don’t get an electric shock? METAL HULL HAS MORE RESISTANCE THAN BODY
  43. types of fuses used in ER, how to test cartridge type fuse (ceramic )
  44. how to select a fuse? BASED ON MAX FAULT CURRENT
  45. Sketch the types of motor starters. Why timer required in autotransformer and start delta types?
  46. How do you trace earth faults?
  47. Trips on an alternator. Motor protection aids?
  48. There is no neutral on board then how do we get 220V supply?
  49. Safeties in Alternator

These are a few of the most frequently asked Function 5 MEO Class 4 Oral questions in MMDs. But, don’t be limited to only these questions. The more questions you solve, the more confident you’ll answer in orals. MEO Class 4 Oral questions can be found from different sources such as forums, WhatsApp groups, Telegram Groups, Facebook groups, and websites.

So, this was a complete set of MEO Class 4 Oral Questions asked on Function 5 EECEOL(Electrical). I hope you found this article helpful.

And, if I have missed any important topic to add, please drop it in the comments.

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