Emergency Generator- Starting, stopping

Emergency Generator

Emergency generators on ships provide power in case the main generators of the ship fail or the ship is in “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.

STARTING

Battery Start:

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

Battery Start

Hydraulic Start:

Put the switch in manual mode as stated above and then check the pressure gauge for sufficient oil pressure Open the valve from the accumulator to the generator Push the spring loaded valve and the generator should start Check voltage and frequency Keep the generator running for 10-15 minutes and check the exhaust temp and other parameters Check the sump level For stopping, use the manual stop button from the panel After stopping the generator, pressurize the hydraulic accumulator to the desired pressure Close the valve from the accumulator to the generator

Hydraulic Start

Automatic Start:

For automatic start, a breaker connects the Emergency Switch Board (ESB) to the Main Switch Board (MSB), and an interlock is provided so that the emergency generator and the main power of the ship cannot be supplied together Open the breaker from the tie line, which can be done from the MSB or the ESB panel After opening the breaker, the emergency generator starts automatically with the help of batteries and supply essential power to machinery and pumps connected to the ESB For stopping the generator, the breaker is closed again and because of the interlock, the generator would go off load Now again put the switch in manual mode to stop the generator Press “stop” and the generator will stop

“The hydraulic and automatic start of the generator must be tried out frequently to ensure that the generator is running fine.”

Power Restoration in Main Switchboard

Emergency generator is used only when the auxiliary engine or main switchboard is not supplying power. Once the main power is restored, following procedure to be followed to manually change the emergency switchboard back to normal supply:

At main switchboard synchronous panel, turn the synchroscopeand voltmeter/ frequency switch to incoming emergency generator position Align the frequency of emergency switchboard and generator with the main switchboard by using governor knob When the point of synchronism is achieved, turn the main/ emergency bus tie to CLOSE position After some time delay (normally 0.5 sec), the emergency generator ACB opens at the emergency switchboard Now the main switchboard is supplying power to the emergency switchboard The emergency generator can be stopped locally

References

The Ultimate Guide to Operating Procedures of Engine Room Machinery. Anish Wankhede [2014]