Question

Advanced Mechatronics

A thermocouple element when taken from a liquid at 50°C and plunged into a liquid at 100° C at time t = 0 gave the following e.m.f. values. Determine the 95% response time. Use linear interpolation inside the intervals. Hint: You must consider 95% of the difference between the final steady state value and the initial steady state value. (Answer: 75s)

Time (s) 0 20 40 60 80 100 120

e.m.f (mV) 2.5 3.8 4.5 4.8 4.9 5.0 5.0

Answer 1

The final steady state value is through observation of result, 50. This is reached at 100 s. The total time period that examined is 100 s. So, far 95% response - = (5 - 2.5) times 0.95 + 2.5 = 4.875 my Now, By interpolation - (4.875 - 4.8)/(4.9 - 4.8) = (x - 60)/(80 - 60) doublerightarrow x = 60 + (4.875 - 4.8)/(4.9 - 4.8) times (20) x = 75 seconds