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Question { 3645 }
Current Capacity of 55sqmm & 80sqmm conductor
Answer
80 sqmm 350A IN AIR 0.6KV
| Is This Answer Correct ? | 1 Yes | 1 No |
Question { 2768 }
how wud i know that whether i have to use unitized package
substation or transformer?
Answer
It is cost,project availability,nature of
project/management decisions decides unitized package unit
because it need less space,compact,modular&safe and
expensive.whwereas procuring transformer need
manufacturing,testing,....Time schedule
| Is This Answer Correct ? | 0 Yes | 0 No |
Question { 3334 }
High Voltage out door substation-annual maintenance, things
to be considered
Answer
1) BOLT CONNECTION ALL EQUIMENTS CHECKING.
2) MAIN EARTH CONNECTION.
3) eARTH SHIELD, fiber optic cable connections.
4) Test the CB TIMING ,INSULATION, PROTECTION RELAYS,
ct,VT, - OIL TESTS, DS,ES,
5)hvac
6) DC system
7) Outdoor lighting/emergency change over.
8) On line sub stn cleaning eauipment
9) funtional test for Bus bar differenctial protection and
its logic sequence restoration of sub stn equipment. if any)
in case of one and half CB sub-station configuration.
10) fire fighting system.
| Is This Answer Correct ? | 1 Yes | 0 No |
what happens to a turbo alternator if it get trip and 1 out
of 3 poles of circuit breaker in close condition
Answer
circuit breaker protection detect ( inverse time overcurent
and earth fault)and trips and isolate the fault.
The turbo alternator can run till negative sequence
charactristic constant limitation.I2t=K. Only generator
winding overheat and some time sparks,de[pends on fault.
It is also observed that major accident took place not only
damaging generator circcuit breaker pole damages,arcs and
body cabinet,arc chute burned,turbo alternater bearing
failure nted.
| Is This Answer Correct ? | 2 Yes | 0 No |
Question { 2815 }
I have 2 Nos of 2500kVA 33/0.415V cast resin transformers.
How to decide on ampere rating of HT Panel?
Also advise me how many panel RMG i have to consider
whether 4 panel ok?
Answer
source or two sources.
your transformer rating is 2500kva, 33/0.42 48/3500A.
THERE IS NO 100A.33KV SW.GR
THE MINIMUM RATING IS 400A,33KV METALCLAD SW.GR, 25KA/1s.
if the sorce is one ,then 3 panel of 33kv sw.gr enough.
If the source is two,then four panel required.
| Is This Answer Correct ? | 0 Yes | 0 No |
Question { 5381 }
what happen if rotor earth fault in AVR system?
Answer
works as usaual.a single dc earth fault will not damage the
device.Just annouces there is weak insulation, trouble
shoot it. rotor is a dc circuit.
Do you mean DC circuit earth fault in avr
caabinet,slipring.
AVR means automatic voltage regulation -i.e when generator
voltage is high or low ,it corrects the filed current and
correct the voltage.
Now if there is a rotor earth fault, the AVR maintains the
voltage but there is current leaking. rotor fault should be
conveys through the air gap or oil film to ground. It is
detected by by a separat rotor earth fault detector known
as singlerotor earth fault. This single rotor must become
double rotor earth fault .Then there is circulating current
flowing and completes grund circuit , till the double earth
fault relay annuciate and isolate the generator.
| Is This Answer Correct ? | 2 Yes | 0 No |
in our 6.6kv motor feeder[it is having two sources from
Bus A&B] earth fault relay is acting, we checked CBCT
connection and cable meggerd values found very good still
earth fault acting during first two are three start after
that it will hold. please clarify what was the reason. if
same motor is starting from other Bus-A it will start.
Answer
tHE EARTH FAULT RELAYS ARE VERY SENSITIVE. INSULATION
RESISTANCE OR MEGGER CAN NOT MEASURE.
CARRY OUT HV CAPACITANCE MEASUREMENT OF MOTOR,CABLE FEEDER.
AND hIGH POT TEST.
MEASURE THE TANGENT DELTA FROM DC HIGH POT.
IF MIN OIL CIRCUIT BREAKER,TEST THE OIL AND REPLACE.
WE ALSO EXPERIENCED THIS DUE TO BURNED CEREMIC/BAKELITE
PARTITION PLATES OF 6.6KV SW.GR
| Is This Answer Correct ? | 0 Yes | 1 No |
Question { 3701 }
I've descovered that when the earth wire in a domestic
electrical installation is not connected back to the board
(ground) a voltage of between 9-24v is is found to be
present in the earth wire.
When connected at the board there is no voltage - is this
normal and why does it happen?
Answer
| Is This Answer Correct ? | 0 Yes | 4 No |
Question { Indiabulls, 18133 }
In a Tap changing transformer where is the tap connected ,
is it connected in the primary side or it is connected in
secondary side
Answer
AS CURRENT IS LOW.
| Is This Answer Correct ? | 5 Yes | 0 No |
Why the ceiling fan rotates in clockwise direction and table
fan rotates in anticlockwise direction.
Answer
anticlockwise for table and ceilinf fans. it is just the
design of fan blades.
But it matter for the exhaust fans.
| Is This Answer Correct ? | 8 Yes | 2 No |
Question { 3327 }
We have a 62.5 KVA DG with Leyland engine and kirloskar
slipring alternator. We have earthed the neutral, and another
earthing for the dg body. is it necessary to isolate the dg
foundation with rubber pads?
Answer
founations are earthed. rubber pads reduce the vibrations.
| Is This Answer Correct ? | 2 Yes | 0 No |
Question { 6704 }
a 650 KVA diesel generator is 1500 rpm, voltage is 415V n full load amps is 805 something,when are applied load more than 400 amps it's voltage is dropping, what is the reasons...?
Answer
| Is This Answer Correct ? | 1 Yes | 0 No |
