Foxboro Controls Flashcards
- On a typical Motor Start Stop (MSS) station what does NAC mean? What does NAT mean?
NAC- Normal After Closed
NAT- Normal After Trip
- What does sliding pressure mean? Constant pressure?
Sliding- will automatically ramp up or down as load goes up or down. Range is 1800-2400 psig. Constant- maintained to setpoint, not dependent load.
- In full boiler master auto, what are the two ways an operator can change throttle pressure?
By manually entering set point or by depressing the arrows
- On the boiler master % output bar, what does it mean if the yellow bar is ahead of the two green bars?
Demand is higher than actual pressure.
- What mode are you in with fuel and air in auto, boiler master and turbine master in auto?
Operator auto
- What mode are you in if only turbine master is in manual and boiler master and fuel-air is in auto?
Boiler follow
- What mode are you in if boiler master is in manual and turbine master and fuel-air is auto?
Turbine follow
- Explain what you would do if one of the throttle pressure transmitters failed.
Bring up pressure transmitter overlay from boiler master page
Compare transmitter readings with actual pressure
Select proper transmitter and select override
Place boiler master back in auto
Write work order for bad transmitter
- What are the two ways to change the furnace draft set point on the furnace draft master?
By manually entering set point or by depressing the arrows
- When can the ID fans be put in auto?
- ID Fan is running and proven
- Shut off damper is open and in auto
- Furnace pressure has been met to set point
- When can the FD fans be put in auto?
. FD Fan is running and proven
- Shut off damper is open and in auto
- Associated ID fan is running and proven
- When can the FD fan Master be put in auto?
Once 1 ID & 1 FD fan is in auto
- What does it mean if the bottom green bar on the FD fan Master % output bar is ahead of the top green bar? What does the yellow bar indicate?
The green bars indicate the percentage of output of each FD fan. (East and West). If the bottom green bar is ahead of the top green bar, the fans are biased higher to the east. The yellow bar indicates the demand of the fans.
- How do you start a boiler purge on the Boiler Status Master?
No trips on boiler No flame detected Aux air dampers modulating All mills off All gas valves tripped Air flow greater than 25% Fans on (Purge will automatically start when all permissives are met and will time out in 5 minutes.)
- When can the Igniter Trip Valve be closed? The Gas Trip Valve?
Igniter trip valve – once all igniters have been taken out
Gas trip valve – once all elevations of main gas are taken out
- What are you enabling when you call up the turbine fuel trip cutout overlay and click on the enable button?
Enable the boiler to tie to the turbine, if one trips the other will trip
- If the boiler will not go into purge, how can you find out what is holding it out?
On the burner control page click the boiler purge permit button and the permissives that have not been met will be highlighted in red
- When the O2 master is in auto, what is it controlling?
FD fan speed to control excess O2 to setpoint
- How do you change O2 set point on the O2 controller?
Excess 02 page click on the up or down arrows or manually enter set point value.
- Explain the two-step operation to trip a condensate booster pump?
Decrease fluid drive to minimum, trip the pump by clicking the safe button click safe button again to get the NAT on the motor control station
- Explain the procedure for enabling the FW/Drum Pressure control.
The controller becomes active when both the startup valve and SUBFP controls are placed in auto and the #3 heater inlet is closed
- What should the set point be for the FW/Drum pressure control?
450-550 psi
- What is the procedure when getting off of the FW/Drum pressure control to #3 inlet valve?
Continually monitor drum level. Between 900 - 1000 psi swap to #3 heater inlet valve. Equalize the feed pump and drum pressure, take the piddle valve to manual and begin opening the #3 inlet valve. As #3 inlet valve opens, back out the piddle valve. If the piddle valve is left in auto it will back out by itself.
- How do you trip the MBFP?
Ensure that the SUBFP is maintaining drum level, decrease MBFP to 3000 RPM and click on the safe button on the MBFP control station.
- What are the permits to latch the turbine on the Turbine Master Screen?
Back pressure below 5” Steam seals I/S Min of 18.5” vacuum EH system I/S Seal oil system I/S Auto stop oil pressure SOB and BOP pumps running, DC oil pump in auto Thrust bearing, low bearing oil pressure, overspeed and low vacuum trips reset Generator alarms reset
- Explain how you would put a coal mill in service by using the coal mill screen.
Have operator check mill and feeder to be started, also load feeder Belt and put in remote.
- Bag house or precipitator in service
- Pull up mill graphic
- Ensure mill ready and ignition permits met.
- Exhauster inlet damper and hot air damper in auto (set point at 150°).
- Exhauster discharge gate open.
- Feeder control station at minimum and in manual.
- Turn siren on 2 minutes prior to starting mill.
- Watch opacity and start on new 6-minute average.
- Start mill motor and watch amps raise and lower to normal
- Open hot air gate, observing temperatures to 110 to 120°
- Start feeder at minimum
- Ensure feeder speed increases to 30% minimum.
- After 50 seconds, slowly increase feeder speed monitoring other feeders ensuring that they equalize.
- Maintain ignition permit for 3 minutes, once feeder speeds are equal place feeder in auto.
- What does it take to get a “Mill Ready” white light located on the feeder motor MSS station? Ignition permit?
Mill ready:
- Breaker racked in.
- Safe run in run.
- Mill temperature <180°.
- Exhauster discharge gate open and limit switch made.
- Tilts at zero and in manual.
- Feeder in remote.
- Feeder inlet gate open and belt loaded
Ignition permit:
- 3 out of 4 igniters in service or
- Adjacent feeder speed above 50% or main gas elevation in service.
- Air flow greater than 30% but less than 40%
- Tilts at zero and in manual.
- On the Generator Master screen, explain how you would put the regulator in service.
- Close in field breaker and ensure you see a “NAC”
- Close in VR control switch
- Observe generator voltage increases to approximately 24KV, do not let voltage exceed 25KV. Open field breaker if voltage increases past 25KV
- Increase voltage with the voltage adjuster to 24KV if needed
- Place voltage regulator mode control switch to “auto” once the “Ready To Transfer” light is backlight
- What control station must be in auto before you can roll the turbine from the ATC Master screen?
Turbine master
- On the LMCC screen, what does it take to get the “Boiler follow” light to light up? Turbine follow?
Boiler follow - place turbine master in manual
Turbine follow - place boiler master in manual
- What must happen in order to get the “MW Control” light to come on?
Boiler master, turbine master and fuel/air must be in auto
- Explain how you would put #8 LP feed water heater in service from the LP feed water heater screen.
Reset heater trip.
- Place A and B valves in auto.
- Ensure set point is at zero.
- Open extraction block valve approx. 20% to warm up heater.
- Once heater is warmed up open extraction block valve fully.
- Explain what will happen if the Water Induction Protection System (WIPS) operates on one of the HP feed water heaters.
It will trip the heater and cause the by-pass to open, once the by-pass is open the inlet and outlet valves on the heater will close. The extraction block valve will also close.
