Air Temp Measurement

Question 1

What is the principle of a Direct Reading Thermometer?

Answer 1

Temp measurement by differential expansion or contraction of mental with temperature

Question 2

What metals are preferred for DRT

Answer 2

Invar and Brass generally

INVAR has low coefficient of expansion

Question 3

What is the principle of a Remote Reading Thermometer?

Answer 3

Electrical resistance changes with temperature and uses Wheatstone bridge and a temperature sensor

Question 4

What material is used for RRT

Answer 4

Platinum wire resistance and Nickel-Plater Beryllium coppe

Question 5

wHY IS tat PROBE ASPIRATED?

Answer 5

In order to measure temp on ground

Question 6

Errors in Temp measurement

Answer 6

Instrument, Environmental & Heating

Not affected due to maneuvering

Question 7

Will TAT always be greater than SAT?

Answer 7

Yes due to heating

Question 8

Formula for TAT

Answer 8

TAT = SAT + (V/100)2

TAT = SAT + Ram Rise

TAT = SAT(1+0.2KrM2)

Question 9

Why are Air Temp Therm shielded?

Answer 9

To protect them from solar radiation

Question 10

What is TAT

Answer 10

Max temp attainable when brought to rest adiabatically

Question 11

Types of therm used in modern a/c

Answer 11

Resistive, Mercury, Thermocouples