Question

A current of $[2+\sqrt{2}sin(sin314t+{30}^{\circ })+2\sqrt{2}cos(952t+{45}^{\circ }\left)\right]A$
is measured with a thermocouple type, 5 A full scale, class 1 meter. The meter reading would lie in the range,

• A. $5A\pm 1\%$
• B. $2+3\sqrt{2})A\pm 1\%$
• C. $3A\pm 1.67\%$
  
• D. $2A\pm 0.5\%$

Answer 1

The correct option is C $3A\pm 1.67\%$


Thermocouple type, instrumetns read rms value,
$I_{rms}=\sqrt{2^2+{\left(\frac{\sqrt{2}}{\sqrt{2}}\right)}^2+{\left(\frac{2\sqrt{2}}{\sqrt{2}}\right)}^2}A$
$=\sqrt{4+1+4}=3A$
For class 1 meter, accuracy is 1% of 5 A range.
$For3A,accuracywillbe\frac{5}{3}=1.67$