Electrical Engineering - what is the instataneous value of voltage in a 3-phase balanced star connected circuit?

GeekInterview.com > Engineering > Electrical Engineering

Go To First | Previous Question | Next Question

Electrical Engineering | Question 10 of 239

what is the instataneous value of voltage in a 3-phase balanced star connected circuit?

Total Answers and Comments: 4

Last Update: October 06, 2007 Asked by: sudhir

Sponsored Links

Best Rated Answer

—

No best answer available. Please pick the good answer available or submit your answer.

July 21, 2006 02:13:07

Karan Sorout

RE: what is the instataneous value of voltage in a 3-p...

Hi all

The 'SUM' of the instataneous value of voltage in a 3-phase circuit (Means at neutral point for balanced load) is used to be 'ZERO'.

But For individual phases this voltage is equal in magnitude but symmetrically 120 degree out of phase to each other.

Now anyone can imagine that 'why 3-phase sytem is used in transmission' not 4-phase or any other system is preferred; as it doesn't need the return wire... Isn't it?

If you feel otherwise then please let me know at karan.sorout@gmail.com

Is this answer useful? Yes | No

October 05, 2006 05:35:27

Vineet

RE: what is the instataneous value of voltage in a 3-p...

Your reasoning is not perfectly correct.1. You don't need return wire only when the 3-phase load is perfectly balanced which is hardly a case in practical scenario. In practical senario transmission system earth is used as return path.2. If system is balanced any n-phase system would not need the return conductor. If you take example of 4-phase system the voltages need to be 90 deg phased in consecutive phases and the sum of voltages across all phases will still be zero and return conductor is not needed. So thats not the reason why 3phase system is used for transmission systems.

Is this answer useful? Yes | No

March 06, 2007 03:56:17

abhishek katkar

Member Since: March 2007 Contribution: 1

RE: what is the instataneous value of voltage in a 3-p...

what happened when we use 2 phase system is their any need to give extra return wire

Is this answer useful? Yes | No

October 06, 2007 04:59:50

cvk

RE: what is the instataneous value of voltage in a 3-p...

The instantaneous voltage at time instant 't' in a three phase balanced circuit assuming that the voltage is applied at reference time ZERO and phase sequence to be +ve ( anti clockwise rotation of vectors) is Em SIN(wt) for R phase Em SIN(wt+120) for Y phase and Em SIN9wt-120) for B. Em is the peak value of the sinusoidal voltage wave.

Is this answer useful? Yes | No

Go To Top

User Name		Remember Me?
Password

Question Bank