# Electrical Engineering - Alternating Current and Voltage - Discussion

### Discussion :: Alternating Current and Voltage - General Questions (Q.No.2)

2.

The conductive loop on the rotor of a simple two-pole, single-phase generator rotates at a rate of 400 rps. The frequency of the induced output voltage is

 [A]. 40 Hz [B]. 100 Hz [C]. 400 Hz [D]. indeterminable

Explanation:

No answer description available for this question.

 Vineeta Verma said: (Jan 8, 2011) f = pn/120 f = 400*60*2/120 f = 400 HZ

 Mahendra said: (Mar 3, 2011) From where did the 60 came please tell me vineeta verma.

 Raj said: (Mar 3, 2011) Because we have to change rps to rpm.

 Talha said: (May 7, 2011) Thanks for that answer.

 Vipul Parmar said: (Aug 17, 2011) F = PN/120 = 400*60*2/120 = 400Hz Because 400*60 rps= 400 rpm.

 Yanusha A said: (Sep 22, 2011) N=120F/P N=400rps=400*60rpm p=2 F=NP/120 =400*60*2/120 =400HZ

 Sandeep said: (Nov 21, 2011) P=2 N= 400 r/s (rps )= 400 r/(m/60)=400*60 r/m =400*60 rpm we know f = N P /120= 400*60*2/120=400 Hz.

 Mau Chau said: (Feb 16, 2012) Thanks raj.

 Pukhraj said: (Mar 17, 2012) Thanks vineeta.

 Vinothkumar said: (Aug 28, 2012) Thanks sandeep.

 Mustafa said: (Sep 3, 2012) If this is a single phase generator , how are we considering the angle to be 120 degrees?

 Ribka A said: (Sep 15, 2012) In three phase generators we will consider the angle between three coils should be 120 degrees.

 Amarendra Dash said: (Aug 28, 2013) We know N = 120F/P. SO F = N*P/120. Here n = 400rps(revolution per second). n = 400*60rpm(rps=Hz=60*rpm). Thus, F = 400*60*2/120. F = 400Hz answer.

 Ahmed said: (Feb 13, 2014) n= 120*f/p. n : rapid per minute. f: frequency. p:no of poles. n=400*60(rps) =24000(rpm). f=n(rpm)*p/120. f=24000*2/120. f=400 HZ.

 Thiru Punk said: (Apr 19, 2015) n(rps) = 400 rps. p(pole) = 2. f = (pn/2). f = (2*400/2) => 400Hz.

 Ch Nikhil Chakravarthy said: (Apr 19, 2015) Since f=1/T. Here f is frequency. T is time in seconds.

 Girishgowda said: (Jun 27, 2015) p = 2. n = 400. rps its converted in to rpm its value is 6.66 rpm. Then f = pn/120. = 2*6.66/120. = 0.111 hz.

 Navya said: (Aug 20, 2015) Where 1sec=1/60min. But how you multiplied 60 in the speed.

 Mrityunjay said: (Aug 20, 2015) Please any one tell from where 2 is came?

 Kalai Sasi said: (Sep 26, 2015) Its a number of poles.

 Jansi said: (Jan 24, 2016) Here given data is: No. of poles = 2; Speed (N) = 400 rps; Usually speed is calculated in rpm. So here we convert 400 rps (revolution per second) in terms of rpm (revolutions per minute). As 1 min = 60 sec; we multiply 400x60 rpm; As we know N = 120f/p. f = np/120; f = 400x60x2/120. f = 400 hz. So hope no one has any doubts regarding this explanation.

 Rakshith said: (Aug 20, 2016) As we all know, Ns = ( (120 * f) /p); Here Ns is in rpm. Therefore, Ns = Ns/60 rps. So, Ns = ((2 * f)/p), And f = ((p * ns)/2), f = 2 * 400/2, f = 400Hz.

 Hassan said: (Aug 29, 2016) How did you guys get that 120?

 Fatima said: (Dec 13, 2016) @Hassan. Formula contains Ns syncronous speed ,Ns = (( 120 * f ) /p).

 Bhanu said: (Feb 7, 2017) Great job @Jansi.

 Waheed Ullah Khattak said: (Feb 16, 2017) If we change RPS to RPM then we should have to divide by 60.

 Surya said: (Aug 16, 2017) N= 120f/p. F= 400*60*2/120. F= 400.

 Sunnyleon said: (Oct 2, 2017) Thank you @Sandeep.

 Kiran said: (Dec 7, 2017) rps=400*60=24000=Ns. P=2 Ns=120f/p 120*f/Ns*p f=Ns*p/120 f=24000*2/120 f=400.

 Feroz Khan said: (May 10, 2018) 1rpm=60rps. so 1rps 1/60 rpm and, 400rps=400 * 1/60 rps. I think the answer is wrong @Kiran.

 D.Jyothi said: (Aug 30, 2018) As per the definition, frequency means that the number of cycles completed by one rotation.

 Asim said: (Sep 2, 2018) Good explanation @Rakshith.

 Mehr said: (Apr 19, 2019) For rpm; Simply convert this to the minute, we multiply 60 with rps 400*60.

 Shoon said: (Aug 24, 2019) 1min = 60sec. If 400rps then 400/60 rpm. As from small quantities to bigger quantities we do division, from bigger quantities to small we do multiplication. Kindly explain it.

 Trupti said: (Apr 21, 2020) rps=400*60=24000=Ns. P = 2 Ns = 120f/p. 120*f/Ns*p. f = Ns*p/120, f = 24000*2/120, f = 400.