-
Potential Transformer
What is the function of a potential transformer?
dhands
- Jun 6th, 2010
Potential transformer is used to measure the high voltage. It is nothing but stepdown transformer. In our metring systems are dsigned only for 110 v or 220 v but we are using 11000, 22000, 33000, ect. For ex PT input is 11000 v but output is 110v.
deepanshu_jadon
- Mar 10th, 2010
Potential Transformer is used to measure VoltageIt is used in protection
-
Range of the Stator Resistance
What is the range of the stator resistance of 3 phase induction motor? To calculate losses for the motors with KW rating of 4, 7.5, 11, 15, 30, 37, 40, 45, 55, 90 etc. On which parameters it does depends on?
-
Zero Powerfactor method of Voltage Regulation
Why we do not use pure capative load instead of pure inductive load?
-
Phase Advancer
Explain What is Phase Advancer?
mallick.subratkumar
- Apr 8th, 2010
It is like an power factor improvement deviceIt maintains the phase sequence of the linelike lag-lead compensator.
-
-
T/F Differential Protection
Can differential protection operate while its only one side is energized or being energized (HT side in this case)? When trying to energize a 132/11KV t/f from HT side when its differential protection operated while its LT side breaker was still open? Was it because of starting inrush current or t/f tap position?(It has an auto tap changer on HT side & while it was being energized tap position was...
pashwuee
- Apr 2nd, 2010
Transformer tripped due to inrush not because of tap changerNumerical relays take care of harmonics during inrush current so transformer does not trips.If it is tripping setting needs to be checked
-
What is the main Electrical IS rules?.
yuvaraj moorthy
- Mar 25th, 2010
ISO is international standard organisation and IS is Indian standarad ...ISO has IEC which is International Electrotechnical Commision will do the standarad for all equipments and each national interp...
vishwas_deshmukh
- May 6th, 2008
IS rules is international standrds rule adopted for any comissioning,erection,or any work we want to perform.They have some certain standads according to study of researcher by comparing all geographical and availabe technical parameteres in that concerning area.Which is suitable for any work.
-
Core cables
generally we are using 4 core or 3.5 core cable for power supply ,in this practice we are connecting three different phase R,Y,B and Neutral to our 4 core or 3.5 core cable,but for our termination conveniences we have connected R phase to all 3.5 core of one cable,Y phase connected to all 3.5core of other cable and B to another and similarly individual cable for Neutral,in sort we use individual cable...
loganathan.1983
- Mar 19th, 2010
3 Phase 4 Wire termination is better because insulation, eathing. Heat is increased according to routing (undergrounding/outer) and load.
expertnayak
- Jun 12th, 2009
Due to use of bundled conductors it will give rise to sheath losses. Which will increase the temperature to overcome this use cross bounding. In overhead lines use both cross bounding and transposition to get a better result.
-
Network Synthesis
Why the roots of the network function are +ve?
deepanshu_jadon
- Mar 10th, 2010
Roots of the network function should be negative for the stability of the function.For positive roots network function is unstable.
-
3 Phase Motors
Why do 3 phase motors rotate in the opposite direction when any two phases are interchanged?
deepanshu_jadon
- Mar 10th, 2010
By the interchange of two phases Force acted in the winding inverse.if motor rotate clockwise then by the changing the two phases it start rotate in anticlockwise direction
M.Mohanraj
- Dec 8th, 2009
Magnitude is different in 3 phases so it is possible to rotate reverse direction.
-
Power Lines
In an AC transmission line(3 phase), If there is a short between any two phases. How will you determine this fault on a protection relay. what will your wave forms look like?
-
-
Phase Sequence
What happens when we change the phase sequence in 3 phase system?
R Raghavendran
- Feb 26th, 2010
Only the sequence of rotation of Magnetic fields changes, which causes a change in the rotor rotating direction accordingly.
SURAJTHEGREAT
- Feb 22nd, 2010
There is no change for ordinary devices,(behaves same as if the unvaried 3 phase supply is given) The rotation direction of the machines varies with variation in sequence of ac supply..
-
LV Switchgear
Considering the short circuit fault, which switchgear is preferable, SFU OR MCCB? Which operates faster?
which one is popular in Indian Market and why? 2) Define SCPD. What is type2 co-odination?
3) Why the contactor rating is higher for the fuseless selection than for fuse selection? whether the ratinf of SFU or MCCB remains the same in both the cases?
4) If...veena_gyanchandani
- Feb 24th, 2010
2) SCPD - Short Ckt. Protection Device.eg - SFU.Type 2 coordination says that there should be no danger to personnel as well as no damage to the controller for downstream faults.Light contact welding ...
veena_gyanchandani
- Feb 24th, 2010
During short ckt. faults, the most reliable switchgear is SFU. It is fastest to operate and takes only few miliseconds. The operator just has to replace the fuse.MCCB is good for overload protection.
-
Life of Earthing Copper Rods
What is the maximum life of earthing copper rods in earthing ground system?
-
Variable and Core Losses
Why copper is called variable loss & core loss is constant loss?
SURAJTHEGREAT
- Feb 22nd, 2010
Iron loss-When an electric current flows through a copper conductor (or any conductor), some energy is converted to heat. i(square)*r...this equation is obvious that iron loss depends on flowing curre...
-
-
Syncronous Generator Flying Off
One advantage of syncronous generator is that there is no possibility of armature conductors flying off. What do you mean by flying off?
-
Energy Conservation Code
What is Energy Conservation Code and why it is required?
-
Find Fault in Underground Cable
How to find out cable fault in a long underground cable?
napster.zatac
- Jan 23rd, 2010
Sectionalizing: it is risky and reduces cable reliability, because it depends on physically cutting and splicing the cable. Dividing the cable into successively smaller sections will enable you to na...
Electrical Engineering Interview Questions
Ans