MMA Assessment OICEW-7-1C

Condition

Aboard ship, in the laboratory, or in an approved simulator given access to proper equipment and manufacturer’s technical manual.

Performance requirement

Location

Assessed in EN‑3233 Steam and Gas Turbines.

References

1. Table A-III/1 OICEW-A4.1
2. NVIC 17-14 Task 4.1.A

Recommended Turbogenerator Startup Procedure (T.S. Kennedy Specific)

Make preliminary checks

1. Check the unit over for operational readiness i.e. no loose gear, all maintenance completed, strainers clean, manhole covers on, zincs intact, etc.
2. Check the oil in the sump. The oil should be at the high mark on the dipstick, in good condition, uncontaminated with water or sludge, and at least 60° F, preferably higher. It can be cleaned and heated via the centrifugal purifier, if necessary.
3. Ensure that the console operated pneumatic valve which controls steam to the generator throttle is closed, and that the generator circuit breaker is open.

Establish cooling water flow through the condenser

1. Open the motorized auxiliary circulating pump high or low suction valve. Use the high suction in port.
2. Open the motorized overboard discharge valve.
3. Open the butterfly valve to condenser shell.
4. Open the butterfly valve to the duplex strainer for the L.O. cooler and the generator air cooler.
5. Start the auxiliary circulating pump. The discharge pressure should be 7-12 psig.
6. Open the auxiliary circ. pump discharge globe valve. Starting a centrifugal pump before opening its discharge valve is good engineering practice, because it reduces the starting load on the drive motor; however, this practice is not always followed.
7. Use the cooler inlet valves to restrict the cooling water flow to the generator LO cooler and air box cooler until they reach normal operating temperatures. (Normal: 110° F oil temperature at the LO cooler outlet, and 40° C generator air box temperature.

Establish cooling water flow through the auxiliary air ejector

Before the turbine is started and when it is operating under low loads, there is insufficient condensate to condense the air ejector steam. Condensate must be recirculated to supply sufficient coolant.

1. Line up the condensate pump suction through the cone strainer, and discharge to the auxiliary air ejector condenser. (Three suction and two discharge valves on TSE).
2. Open pump casing vent valves (Two on TSE).
3. Open pump sealing water supply valve.
4. Start the condensate pump, and open the condensate pump discharge valve.
5. Open the recirc. regulator hand bypass valve from the outlet of the air ejector about one turn.
6. Watch the level in the hotwell, and adjust the recirc flow to keep the level low in the sight glass. If the recirc valve is opened too wide, the hotwell will flood and the DC heater level will fall.

Start the Hydraulic Pressure Unit (HPU)

The Woodward speed control governor requires an external oil supply at a pressure of approximately 150 psig to operate the steam throttle valves. The HPUs are located on the lower level, starboard side.

1. Check the sump oil level of the HPU for the SSTG to be started.
2. Start either pump 1 or pump 2.
3. Place the selector in auto, which will place the other pump in standby mode.
4. Check the differential gage on the duplex discharge strainer when unit is running. One to two psig is normal.

Establish lubrication for turbine and reduction gears

There are thee separate lube oil pumps on the unit: a hand operated rotary pump, an attached IMO pump which is driven off the reduction gear, and a motor driven auxiliary oil pump. The turbogenerator sump holds 140 gallons of 2190-TEP oil. Additional oil can be added via the purifier, or by hand through the sump fill plug near the dipstick. The unit also has a duplex strainer that should be cleaned and changed daily.

1. Start the auxiliary oil pump.
2. Check pump discharge pressure: it should be about 90 psig. Oil pressure will open the steam throttle trip valve.
3. Check oil pressure to the bearings: it should be 10-15 psig.
4. Check bull’s eyes for oil flow from all bearings.

Line up steam supply

The generators are supplied with superheated steam at 600 psi, 850°F through a manual turbogenerator steam stop at each boiler, and a manual stop valve and a console operated pneumatic valve at each generator. Steam lines should always be drained and warmed up before admitting steam to a turbine.

1. Open the three steam traps on the turbogenerator.
2. Open the steam stop valves at the generator.
3. Open the generator stop valves at the port and/or starboard boiler.
4. Open the drain before the control valve to the bilge slowly.

Raise vacuum

Note that each auxiliary air ejector is duplex: two complete sets of first and second stage ejector nozzles. Only one is normally used at a time.

1. Line up vapor path: open first stage suction from condenser, second stage suction from intercondenser.
2. Line up air ejector drains: Open inter condenser loop seal drain line to the auxiliary condenser. There is no valve in after condenser drain line to the atmospheric drain tank.
3. Open 150 psi steam to the gland seal regulator and adjust it to 1.5 to 2.5 psig.
4. Admit 150 psi steam to second stage air ejector nozzle. When the condenser vacuum reaches approximately 20 inches Hg, admit steam to the first stage. The vacuum should rise to 28-29 inches Hg.
5. Adjust the recirc flow to maintain a condensate temperature of 90 to 125° F at the outlet from the air ejector condenser.

The turbine should be started spinning without delay after the vacuum is established to prevent the rotor from standing still in a hot environment, which would cause the rotor to bow and cause vibrations. Delaval recommends leaving the gland seal steam off until turbine is spinning to lessen the chance of rotor bowing.

Idle and warm up the turbine

1. On the console:

1. Set _voltage regulator_ control to OFF.
2. Set IDLE-RATED selector to IDLE. This will set the speed governor set point to the idle speed of 2900 rpm.
3. Set selector to RUN. 
4. Manually reset lube oil trip on front end of turbogenerator by pulling up on the round knob.
5. Open pneumatically controlled steam valve using the pneumatic steam stop valve control knob located on the main console.
6. Press the green start bypass button. The unit should start and run at approximately 2900 rpm. 

1. Walk around the generator and check for any problems such as water or lube oil leaks, unusual noises, etc. If in doubt, shut the unit down.

Bring the turbine up to speed

1. Allow the turbine to idle for about 30 minutes if possible, or at least until the oil temperature reaches 90°F. The generator should not be run above idle speed until the lube oil temperature reaches 90° F.
2. Set IDLE-RATED selector switch to START. This sets the governor set point to the rated speed.
3. Open the pneumatic valve fully: 71 psig air pressure. The turbine speed should rise and then stabilize at 10,012 rpm as the governor takes control.
4. Set the voltage regulator control to AUTOMATIC.

Watch the unit carefully

• Keep your eye on the vacuum, oil pressure and temperature, air box temperature, and condensate temperature.
• Start cooling water to the lube oil cooler when the oil temperature comes up, and adjust to maintain 110° F.
• Adjust the cooling water flow to the air box to maintain 40° C.
• Adjust or secure recirc as necessary to maintain condensate temperature and hotwell level.

When you are satisfied with the operation of the turbo-generator, you can put it on the line.

See the Assessment Guidelines for additional specifications of behavior and standards.