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5th Class Power Engineering Assignment 2 questions and answers.
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5th Class Power Engineering Assignment 2 questions and answers.
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5th Class Power EngineeringAssignment 2 questions and
answers
You are the operator of a steam heating boiler with an automatic
programming controller and safety switches. The Boiler is not firing
up even though there is a demand for steam. List the possible
causes and remedy for each - answer Spark but no flame, laco of
fuel due to closed manual valves, clogged oil filter, empty fuel tank,
and incorrect pilot gas pressure. Inoperative solenoid, or low fire
fuel valve
You are the operator of a steam heating boiler with an automatic
programming controller and safety switches. The oil burner does not
light although there is a demand for steam and the blower starts.
List the possible causes and the remedy for each - answer No oil
flow comes out of the burner, check that the oil tank that float
gauge is not stuck, check for a dirty or clogged oil filter. Remedies
would be resetting, and cleaning up the pilot flame
You are the operator of a steam heating boiler with an automatic
programming controller and safety switches. There is no main flame
ignition. list the possible causes and the remedy for each - answer
Insufficient pilot or low fire flame, adjust pilot or low fire flame
You are the operator of a steam heating boiler with an automatic
programming controller and safety switches, the boiler is operating
normally and suddenly shuts down although there is still a load
demand. List the possible causes and the remedy for each - answer
Inoperative damper motor, check motor for cause and replace if
necessary
,For the controller shown in the figure in question 56 explain how the
startup sequence is controlled after the timer motor has been
energized until it stops after the burner is lit - answer The flame
failure relay in the control circuit of the main fuel valve is closed
only when the scanner sights the flame of either the pilot or the
main burner
For the controller shown in figure in question 56, explain how the
startup sequence is controlled after the timer motor has been
energized until it stops after the burner is lit. - answer The flame
failure relay in the control circuit of the main fuel balance is closed
only when a the scanner sights the flame of either the pilot or the
main burner
For the controller shown in the figure in question 56 explain how the
shutdown is initiated and how the controller sequence operates to
shut down the boiler - answer Closing the main stop valve will shut
it off
How long after the starting after the starting switch that is closed
does the air flow switch have to prove that the fan is operating
correctly to complete a successful lineup - answer 0 Seconds
Explain what check is made 30 seconds after the timer starts and
what conditions must be satisfied. Also explain what happens if this
condition is not satisfied - answer Checking the timer, timer stops if
fuel pressure is not closed
Explain what occurs 37 seconds after the timer is started and how
long does the process have to succeed. If the process fails in this
length of time, explain what occurs - answer End of purge period.
Ignition transformer energized, igniter starts sparking. Fuel Valve
opens. Start of ignition
Explain what occurs 60 seconds after the timer is started and how
long does this condition exist. Also name some devices that would
, end this condition and what happens then - answer End of startup
Cycle. Beginning of normal firing period. Timer stops, burner and
blower remain in operation until heat demand is satisfied, and
operating control reaches its cutout point
Describe the operation of a photoelectric cell - answer A photocell
operates on semi conductor operates on the semiconductor
photoconductivity the energy of photons hitting the semiconductor
frees electrons to flow decreasing the resistance
Describe the operation of a stack switch - answer Switch taking is a
term that describes a technique for linking networking switches
together. Stack switches are connected in such a way that the
multiple units operate as if they were a single device
Describe the manner in which an operating control for a hot water
boiler differs from an operating control for a steam boiler - answer
This safety device works on the same principle as low gas pressure
fuel cut-off switch. If for any reason the gas pressure supplied to
the burner increases beyond the maximum required for safe
combustion, The switch will open up and the fuel supply will be cut
off
Describe how a thermocouple operates. Also state the approximate
voltage generated by a thermocouple and how this voltage could be
increased - answer A thermocouple consists a of two dissimilar
wires welded together at one end to form a measuring or hot
junction, while the opposite ends are connected to an electric circuit
at the cold junction. Approximate voltages generated by a
thermocouple is 30 Millivolts, a transformer is used to provide
sufficient power to operate the main valve
Flame Rod - answer Another type of flame detection system, a flame
rod uses the principle that a flame is capable of conducting
electricity
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