Electronics and Communication Engineering - Measurements and Instrumentation - Discussion

Discussion Forum : Measurements and Instrumentation - Section 1 (Q.No. 3)
3.
The coil of a moving iron instrument has a resistance of 500 Ω and an inductance of 1 H. It reads 250 V when a 250 V dc is applied. If series resistance is 2000 Ω, its reading when fed by 250 V, 50 Hz ac will be
260 V
252 V
250 V
248 V
Answer: Option
Explanation:

Discussion:
30 comments Page 3 of 3.

Deepshikha said:   9 years ago
Why not considered the 2000 ohm resistance for dc current?

Sneha.v.k said:   8 years ago
V/(R+jXl).
250/(2500+j (2πfl)).
250/(2500+j 314.159).

Pipo said:   9 years ago
Find first fall Idc.
Find Iac.
Reading = iac/idc * 250.

Avinash said:   7 years ago
Here, We need to find the Impedance. X=πr^2+XL^2.

Skm said:   8 years ago
How we calculate i taking j?

Please help me.

Lou said:   9 years ago
It should be 250/(2500+j314) to get 0.09922.

Annu kumari said:   1 decade ago
From where you put the value of j314.16?

Cheetha said:   1 decade ago
Inductive reactance = 2*pi*f*L.

Prabhas said:   9 years ago
The value of φ = (22/7).

Rakesh said:   5 years ago
Clearly explained.


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