Electrical Engineering - Magnetism and Electromagnetism - Discussion

Discussion Forum : Magnetism and Electromagnetism - General Questions (Q.No. 12)
12.
A basic one-loop dc generator is rotated at 90 rev/s. How many times each second does the dc output voltage peak (reach maximum)?
90
180
270
360
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
13 comments Page 1 of 2.

Makwazir said:   1 decade ago
In one sec it will reach at 180 peak, once is for +ve peak(90) and another is -ve peak 90. So answer is 180.

Naresh said:   1 decade ago
What is the meaning of one loop ?

Pasupathi said:   1 decade ago
One loop represents one full cycle. i.e 0 to 180 degrees. In one second, it will reach positive max and negative max. i.e. 2 times. therefore, 90 rev/s corresponds to 180 times.

Silambu said:   1 decade ago
Here taking 2 cycles per 1 revolution in one loop generator.

So, 90 rev = 2*90 =180.

Now 180 times will reach the maximum peak value.

Ra chaudhari said:   1 decade ago
1 cycle is completed in 1 revolution. And in one cycle it obtains two times max value. Therefore 2*90 = 180 times.
(1)

Jumper said:   1 decade ago
Guys it has been mentioned that its DC. So only +ve peak twice in one cycle.

Satieins said:   1 decade ago
F = NP/120.

Basic one loop generator has two pole.

N = 90*60 rpm.

F = 5400*2/120 = 90.

Answer is 90*2 = 180.
(1)

Raj said:   1 decade ago
What is F?

Raki said:   1 decade ago
F is frequency and what is that 2?

PradeepRaj said:   1 decade ago
It is given 90 REV/sec. So frequency is 90 Hz (i.e 90 complete cycles).

It has 90 +ve half cycles and 90 -ve half cycles.

Since it is DC generator, due to action of commutators (split rings) and carbon brush the -ve half cycles are rectified into +ve half cycles.

So in total, it got 180 peaks.

Happy learning.
(4)


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