Ways of starting and testing emergency generator

Emergency generator on ship provides power in case the main generators of the ship fails and creates a “dead or blackout condition”. According to general requirement, at least two modes of starting an emergency generator should be available. The two modes should be – battery start and hydraulic or pneumatic start.

The Port state control (PSC) might detain a ship or provide some time to correct any kind of deficiency found if the second mode of starting is not operating.

Testing of Emergency Generator

The testing of ship’s emergency generator is done every week (as part of weekly checks) by running it unloaded to check if it starts on battery mode. The hydraulic start is done every month to ensure that it is working fine. Also every month automatic start of generator is also done to check its automatic operation and to see whether it comes on load.

emergency generator

Procedure for Battery Start

  1. Go to the emergency generator room and find the panel for emergency generator.
  2. Put the switch on the test mode from automatic mode. The generator will start automatically but will not come on load.
  3. Check voltage and frequency in the meter.
  4. Keep the generator running for 10-15 min and check the exhaust temp and other parameters.
  5. Check the sump level.
  6. For stopping the generator, put the switch in manual and then stop the generator.

Procedure for Hydraulic Start

  1. Out the switch in manual mode as stated above and check the pressure gauge for sufficient oil pressure.
  2. Open the valve from accumulator to generator.
  3. Push the spring loaded valve and the generator should start.
  4. Check voltage and frequency.
  5. Keep the generator running for 10-15 min and check the exhaust temp and other parameters.
  6. Check the sump level
  7. For stopping, use the manual stop button from the panel.
  8. After stopping the generator, pressurize the hydraulic accumulator to desired pressure.
  9. Close the valve from accumulator to generator.

Procedure for Automatic Start

  1. For automatic start, we know that there is a breaker which connects Emergency Switch Board (ESB) and Main Switch Board (MSB); and there is also an interlock provided due to which the emergency generator and Main power of the ship cannot be supplied together.
  2. Therefore, we simulate by opening the breaker from the tie line, which can be done from the MSB or the ESB panel.
  3. After opening the breaker, the emergency generator starts automatically with the help of batteries and will supply essential power to machinery and pumps connected to ESB.
  4. For stopping the generator, the breaker is closed again and due to the interlock the generator becomes off load.
  5. Now again put the switch to manual mode to stop the generator.
  6. Press stop and the generator will stop.

You may also like to read – Free Sample:Generator Running Tests


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  1. Can anyone shed light on how the blackout situation is rectified. I am interested in how the battery is able to crank the emergency generator to get it running when this is the system used

  2. Dear karthik,
    The emergency switchboard safeties are the same as main switchboard. In emergency generator there is lube oil low pressure alarm, fuel leak alarm and belt cut alarms only. That is in most japan built ships. I hope it answers yous question

  3. HI,
    Could you tell me as to what are the most common specifications for an emergency generator (diesel powered) and alternator’s specifications too.????


  4. can any one explain me how is the interlocked connected between msb and esb? how the emergency gen starts automatically when main gen fails??

  5. Can anyone tell that generator is running & acb is closed frequency is also same but generator isnot coming onload what can be the causes

  6. Are there any specific SOLAS or IMO requirement regarding the duration of the monthly test of an emergency generator on a MODU? I have seen some recommendations but nothing official.

    Some say it should be ran for 1 hour and some say only 30 minutes.

  7. What is harbour mode and procedures for running emergency generator in harbour mode (Hyundai switchboard)?

  8. @Koshal: The emergency generators switchboard is provided with this mode so that it can be used during laytime in port for the supply of the ship mains.

  9. How it starts automatically ? What mechanism is used to sense that the voltage has dropped so the em. Gen should start?

  10. How an an Emergency Generator is maintain in a condition ready for immediate starting?
    consideration which must be taken in the event of the emergency generator being unavailable for use?

  11. Hey guys,i leave some important matters about those questions that raise by some friends out there.
    First and foremost, if power outrage prevailed obcourse interlocking device that connected both ESB &MSB will activate. In ESB there is BUS TIE ACB once during sense voltage breakdown it send signal to UVT for this reason other electrical components activated relay and timers that trigger to start the engine after 28 seconds. Engine started established voltage 440vac and frequency at 60hz about 40-45 seconds ESB ACB closing to line. Once the Diesel generator run and retrieve normally the power management system will follow and automatically activate the interlocking device at BUS TIE AIR CIRCUIT BREAKER thus emergency generator to stop additioally depending in the program if auto or manually stop the engine.

    You can possibly test this scenario by switching sequencial test: Engine (without load)/ Engine&Acb(with load and power blockout arise)..

    God bless all..

  12. @jumbo: There is an option of “Simulation” which be activated by pulling a fuse in the autostart panel which supplies the under-voltage or under-frequency relay.
    The emergency generator can be tested even when the main supply is active.

  13. Regulation for emerg generator. What is the time it should come on load when power fails off

  14. Dear Jhayskie, recently My Ship have Problem regarding E’Cy Generator that Unable take place when Balck Out test. FYI My E’cy Generator can start Automaticaly and Hz, Voltage showing normal ( Power present in the Line ) when BlackOut but the Problem is the E’cy ACB unable to close or connected to the Main Line. Would you like give some help to rectify it??? Or Any One ?

  15. After sensing low voltage in esb what all things happen to start generator electrically ??

  16. Hi Guys,

    I would like to draw your attention to a very particular question.

    ” If the Main Switchboard becomes dead, there is no 24V supply available either as the batteries are flat and Emergency Generator does not start automatically. Now Emergency Generator can be started manually but how the Emergency Generator can then be connected to Emergency Switchboard ?? ”

    Please note there is no 24V supply available which runs the controls on Emergency Switchboard.

  17. in normal circumstance the batteries are stby with load switch open and charging switch closed.this position held by electro magnetic coil against pressure on the spring.loss of main power has the effect of decharging the coil.so that the load switch moved to closed the circuit by spring pressure.so circuit is now closed and supply to starting motor via battery and emcy generator will start.

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