Emergency Generator: Testing & Requirements

1. Purpose & Starting Modes

• The emergency generator on a ship provides power in case the main generators fail, creating a dead ship / blackout condition.
• According to the 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.
• Port State Control (PSC) might detain a ship or provide some time to correct any deficiency found if the second mode of starting is not operating.

Why two modes? If the battery is flat, the generator must still start by hydraulic/pneumatic energy; if that fails, the battery remains. Two independent stored-energy sources guarantee the emergency generator can start when the ship has blacked out — which is exactly when it is needed.

2. Testing Schedule

Routine weekly check:

• Carry out the routine start test at the interval in the vessel’s procedure. Where safe and provided for, the test may simulate loss of normal power and prove the automatic start signal and transfer arrangement.

Other tests at the intervals in the vessel’s approved procedure:

• Prove each independent starting mode and the automatic start/changeover at the interval and by the method specified in the vessel’s approved testing procedure.
• Supplement short no-load runs with a proper load test at the prescribed interval; only a load test demonstrates the prime mover, alternator, breaker and interlocks under load.

Remember the pattern. Weekly testing commonly includes a start run and may simulate loss of normal power. The exact second-mode, automatic-changeover and load-test intervals come from the vessel’s approved procedure. A brief no-load run does not prove rated-load performance.

3. Battery & Hydraulic Start Procedures

Procedure for Battery Start:

1. Go to the emergency generator room and find the panel for the emergency generator.
2. Put the switch on 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. Run it for the duration specified by the approved test procedure; monitor exhaust temperature and other operating 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. Put the switch in manual mode as above and check the pressure gauge for sufficient oil pressure.
2. Open the valve from the accumulator to the generator.
3. Push the spring-loaded valve and the generator should start.
4. Check voltage and frequency.
5. Run the generator for the duration specified in the approved procedure and check the exhaust temperature and other parameters; check the sump level.
6. For stopping, use the manual stop button from the panel.
7. After stopping the generator, pressurise the hydraulic accumulator to the desired pressure.
8. Close the valve from accumulator to generator.

Don't forget the accumulator. After every hydraulic start, the accumulator must be re-pressurised and the supply valve closed — otherwise the second starting mode will not be ready next time. This is a common PSC finding.

4. Automatic Start, EGS Requirements & Power Supplied

Procedure for Automatic Start:

• A breaker connects the Emergency Switch Board (ESB) and the Main Switch Board (MSB), with an interlock so that the emergency generator and the main power cannot be supplied together.
• To test, simulate by opening 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 on batteries and supplies essential power to the machinery and pumps connected to the ESB.
• To stop, the breaker is closed again and, due to the interlock, the generator becomes off load; put the switch to manual mode and press stop.

Requirements for Emergency Generating Sets:

• Requirements involve starting in cold condition and starting energy-storing devices.
• Emergency generating sets shall be capable of being readily started at a temperature of 0°C; if impracticable or lower temperatures are likely, heating arrangements shall be provided.
• Each automatically started set shall have approved starting devices with stored energy for at least three consecutive starts.
• A second source of energy shall be provided for an additional three starts within 30 min, unless manual starting is demonstrated to be effective.
• Stored energy maintenance: electrical and hydraulic systems from the ESB; compressed air from main/auxiliary receivers through a non-return valve, or an emergency air compressor (if electric) from the ESB; all starting/charging/energy-storing devices located in the emergency generator space.
• Where automatic starting is not required, manual starting is permissible (manual cranking, inertia starters, manually charged hydraulic accumulators, powder charge cartridges) where demonstrated effective.

Power Supplied by the Emergency Generator:

• On failure of the main power generation, the emergency/standby system ensures essential machinery keeps the ship operating; batteries, an emergency generator, or both may be used.
• Essential systems supplied include: (a) steering gear; (b) emergency bilge and fire pumps; (c) watertight doors; (d) fire-fighting system; (e) navigation lights and emergency lights; (f) communication and alarm system.
• The emergency generator is normally located outside the machinery space, to avoid situations where access to the engine room is not possible; a switchboard in the emergency generator room supplies the essential machinery.

Surveyor asks: "How do you test the emergency generator?" Describe the vessel’s routine schedule and approved test procedure, then explain the independent starting arrangements, applicable stored-energy capacity and the essential services supplied.