MT3 (Exam 3) Flashcards by Catawba Initial License Class

What is the purpose of the turbine low speed switch?

-Starts and engages the turning gear
-Prevents turning gear from attempting to engage if the aux shaft should fail
**Aux shaft must be less than 1.5rpm
**Disabled above 100rpm

How well did you know this?

Not at all

Perfectly

What drives the turbine main oil pump?

Driven from the stub rotor (Control rotor) mounted on the aux shaft

How well did you know this?

Not at all

Perfectly

What is the purpose of the turbine magnetic speed sensors?

-Used for EHC and aux speed sensor units
-A different sensor provides speed signals for turbine supervisory instruments
**Mounted in front standard

How well did you know this?

Not at all

Perfectly

What is the purpose of the turbine shaft grounding device?

-Removes shaft voltages and sends them to ground
-Prevents lube oil breakdown
-Prevents pitting of bearing surfaces
**Located between the “C” LP turbine and main generator

How well did you know this?

Not at all

Perfectly

What are turbine trip setpoints for thrust bearing wear?

-Pre trip alarm @ 20mils (1/4)
-Trip @ 42mils (3/4)

How well did you know this?

Not at all

Perfectly

How many thermocouples in the Low pressure turbine inlet?

-2 per turbine (6 total)

How well did you know this?

Not at all

Perfectly

How many thermocouples in the 8th stage extraction?

-4 per LP turbine (12 total)
**“D” extraction steam
** Rapid decrease in lower hood temp is indicative of water induction

How well did you know this?

Not at all

Perfectly

What does the turbine Eccentricity Detector Measure?

Shaft straightness

How well did you know this?

Not at all

Perfectly

What is turbine differential expansion indicating?

The difference in expansion between the rotor and the HP turbine shell
**Rotor expansion measured between the LP turbine and the generator

How well did you know this?

Not at all

Perfectly

Where are turbine vibration detectors?

-2 vibration assemblies per bearing (2 sensors/assembly)
-Shaft relative motion sensor (measures amount of shaft movement relative to the bearing (mils))
-Bearing cap motion sensor (Measures the level of vibration of the bearing cap)

How well did you know this?

Not at all

Perfectly

Does the TSI panel perform any control functions?

How well did you know this?

Not at all

Perfectly

What does the turbine emergency trip system (ETS) do?

-When in the tripped state (depressurized), overrides all opening signals and trips the:
-Main stop valves
-Reheat stop valves
-Control valves
-Intercept valves
-Extraction check valves

How well did you know this?

Not at all

Perfectly

What two valves are required in order to actuate an ETS trip signal?

-Mechanical Trip Pilot Valve (MTPV)
-Electrical Trip Solenoid Valve (ETSV)

How well did you know this?

Not at all

Perfectly

How is the turbine Mechanical Trip Pilot Valve (MTPV) actuated?

Operated by the trip latch, which is tripped by the trip finger. The trip finger is operated by:
-Mechanical O/S device
-Mechanical trip piston (held in reset by LT pressure and trips via MTSV when pressure is lost)
-Manual trip handle

How well did you know this?

Not at all

Perfectly

How is the turbine Electrical trip solenoid valve (ETSV) actuated?

ETSV has a single 24VDC solenoid which is normally energized. Upon generation of a 24VDC trip by the T&M system, the solenoid is de-energized which trips the ETSV.

How well did you know this?

Not at all

Perfectly

Turbine trip from Steam Generator Level?

Study These Flashcards

P-14 will cause turbine trip

Turbine trip from low main oil pump discharge pressure?

Study These Flashcards

2/3 less than 100psi
**when greater than 96% speed

Turbine trip from exhaust hood high temp?

Study These Flashcards

1/3 >225F when <60% load