in power station what is the electrical circuit length of
spacing between power transformer and lightning
arrestors,for the voltage system of
230kv,110kv,33kv,22kv,11kv?

Why is it preferred to use a wattmeter(s) to measure power
in three phase systems rather than using a combination of
other instruments e.g. voltmeters, ammeters etc?

when we gave dc supply to 220v dc motor its rpm is 1200.
then we gave 180v. how many rpm of its motor.
gave answer with calculation at my ID.... ravizak@ymail.com

hi,
i have 3x200KVA and 2 x 80KVA UPS with battery bank of
150AH 68Nos. and 100AH 204Nos., i need to install AC either
ductable or PAC type, so can you help me to calculate heat
load and capacity of the AC to install.

Why 3 over-current and 1 earth fault relay is used on
primary side of transformer? Why 2 over-current and 1 earth
fault relay in used on secondary side of transformer?

i have dry type transformers can you help me that how many
tests i can do to know the performence of transformer and
also please tell me about the BDV test and Insulation
resistance test in oil cooled transformers

why can we use cosine wave instead of sine in ac supply as
both have same rms vale and ripple factor

48

if we look on phasor of the transformer vaoltage is 180
oppsite at primary and the secondary so to improve a power
factor is secondary should kept negative to improve it
primary side
means is -.90 became +.90 at other side

154

why does a dc machine has high efficiency while working as a generator than as a motor ..

175

My question is whether bellow formula is correct to find bus size for 46kA for 0.5 second & what is RT in bellow formula.
formula to calculate the size of busbar to withstand the thermal stresses due to currents with duration of 0.2 sec to 5 sec.
Sp = RT( I x I x t) / K
Where Sp – is the cross sectional area of bus bar in millimeters.
I - is the value of AC fault current.
t - is the operating time of disconnecting device in seconds.
K – is the factor depending on the material of the conductor, insulation and initial and final temperature.
Value of ‘k’ for copper is 143.

12

what is the breaking capacity and making capacity of circuit
breaker and how

152

If ct ratio is 250/1 and mtr is of 5 amp, what will be mf?

132

sir,
i am 3 years diploma course pass out candidate.what type of
certificate can i got in marine service.

221

Why using synchronising methed in DG's sets?

188

how does commutator convert a.c to d.c?

160

difine electrical ballast in HPSVL

160

In constant power region of 3-phase IM torque-speed
characteristics, if frequency increases slip
A does not alter B decreases
C increases D none of above

92

what happen when increase or decrease size of
lamp,light.glass.

155

My question is abt backlog.I had dropped one subject in my
second year, and completed this subject in the 3rd attempt,
so how many backlogs i have got?1 or 3?plz sujjest the
answer as soon as possible

282

How to calculate flow of water delivered by pump when
pressure & size of pipe line is given