javad ahamad k.v


{ City } calicut
< Country > india
* Profession * trainee
User No # 44740
Total Questions Posted # 13
Total Answers Posted # 14

Total Answers Posted for My Questions # 16
Total Views for My Questions # 77529

Users Marked my Answers as Correct # 104
Users Marked my Answers as Wrong # 51
Questions / { javad ahamad k.v }
Questions Answers Category Views Company eMail

difference b/w current and voltage relay?

 1 Electrical Engineering 2784

when voltage increases then current also increases then what is the need of over voltage relay and over current relay? can we measure over voltage and over current by measuring current only?

 1 Electrical Engineering 5532

why an ac solenoid valve attract the plunger eventhough we interchanges the terminal?will the ploes changes?

 1 Electrical Engineering 3629

why we are using large cross section cable at load side and small at other (11kv to trsfr)side of transformer? when the load increses current at both side increases,right?

 2 Electrical Engineering 4446

1.After synchronising the alternator to the grid,how we r delivering power to the grid?if the i/p increases does the speed hence frequency increases? 2.y the power factor is changing when exitation changes?what is the relation with p.f and flux?

BSNL,

4 Electrical Engineering 9051

what is relay type VDG,CDG,VTT ect?

Bhel,

1 Electrical Engineering 11961

what is power frequency withstand and impulse withstand of a circuit breaker?

Power Grid,

2 Electrical Engineering 21844

what is isochronous mod? what is voltage drop mode and p.f mode?

ABB,

Electrical Engineering 2602

what is ic 01,ic 06 ?is it types of cooling?

Bhel,

Electrical Engineering 3768

how Local Breaker Backup relay working?

 1 Electrical Engineering 3934

How Id and Ires are calculated in siprotech 7ut612 and abb trsfmr differential relay.what is the formula

 1 Electrical Engineering 2841

How harmonic block test are conducted on relays ( Siemens,Areva ect )power transformer using omicron kit?

Siemens,

Electrical Engineering 1743

why trip circuit supervision is taking through breaker contact? what happen if takendirectly?

GE,

2 Electrical Engineering 3394



Answers / { javad ahamad k.v }

Question { PSEB, 29714 }

what is the wattage of 'zero watt' bulb?


Answer

it is less than 5 watt

Is This Answer Correct ?    0 Yes 14 No

Question { 7636 }

if we increase the frequency given to a transformer then wat
will happen to the transformer size, whether it will increase?


Answer

No.there is an expansion and contraction in each cycle.cld
magnetostriction,hence producing humming sound. if we
increas the frequency the rate of exp n con increase.

Is This Answer Correct ?    2 Yes 5 No


Question { 8918 }

how to reduce humming noise in transformer?


Answer

gopi s answer s correct

Is This Answer Correct ?    5 Yes 2 No

Question { 4627 }

we have a 2000kva step down transformer at our site. The HT
side is charged from 22000V. So the primary current will be
52.48A. So why the HT breaker(SF6 ABB) is rated of
1250Amps ?


Answer

i thing the cb is coming at standered rating.but if fault occures the current will go beyond 1250 defenitly.therefore no problems

Is This Answer Correct ?    2 Yes 3 No

Question { HMT, 5841 }

explain harmonics in simple words..........


Answer

before 1960 actually harmonics was very little.but todays world we have so many electronics equipments like computer, tv,washing machines ect...these equipments draw some more current for short interval of time.therefore the actual sinusoidal wave hasbeen changed for that time.this is happen in all the distribution system.it s the odd multiple of fundamental wave,like 3rd harmonic,5th harmonic ect...we r using harmonic filter to avoid it..

Is This Answer Correct ?    2 Yes 2 No

Question { 13065 }

What is the value of specific gravity in charged lead acid
batteries.


Answer

it should be between 1.185 to 1.205.

Is This Answer Correct ?    7 Yes 4 No

Question { 4746 }

what is restircted earth fault relay,how it works? what is
diffrance btwn normal earth falut relay & restricted earth
fault relay?


Answer

both e/f relays are different. consider an alternator, its
neutral is earthed through a
resistance inorder to limit earth fault current .then we
cant protect the 100% winding from
differential e/f relay only.because if an e/f occurs at
very near to neutral point the driving
current to operate relay will be very small. there for it
cant be sensed by this method,
we can protect up to 80%(approximate value.depent upon
resistance)only.at this situation
we r providing a restrcted e/f relay to protect the
remaining winding ie 20%.this relay
have very low current setting.by the combination of these
two we can protect 100% winding.

Is This Answer Correct ?    6 Yes 0 No

Question { 7259 }

can you explain the rms value in simple words....


Answer

rms value is expressed in terms of dc. suppose we have a
simple resistive ckt. first we connected a dc source and
applied a certian voltage then noticed the heat produced
in the resistor.then we replae the source by ac and we
adjusted the souce to such a value that it produce the
same heating affect when the dc is applied.that value is
called rms value of ac.

rms value is less than peak vale.

Is This Answer Correct ?    14 Yes 0 No

Question { 2959 }

why pull the single core cable?


Answer

to cancel inductive effect.

Is This Answer Correct ?    0 Yes 0 No

Question { 3101 }

why we used.c source in the field of the alternator , why
not a.c source.


Answer

suppose the field is rotating and the armature is
stationary,we r applying dc to field. consider a single
conductor of armature. according to that conductor,while
rotor rotate say north pole is coming and have maximum
intensity then to low afterthat south pole is coming maximum
valu then minimu again norht. ie with respect to that
conductor it feel a sinusoidal flux.
if we are applied ac then we will not get sinusoidal
flux,hence cant produce sinusoidal emf.that is y.

hope my answer is correct

Is This Answer Correct ?    5 Yes 4 No

Question { 6042 }

After synchronization with grid how to maintain the
power factor in lagging or in leading? if lead of lag what
is the problem?


Answer

both lagging and leading p.f will badly affect the system
we have to maintin unity p.f.
lagging and leading p.f will take more current from the
alternator for the same equipment.

eg: power taken by a motor = v*i pf
= 230*20*1= 4600 w
suppose if the p.f is .6 either lagg or lead
in order to get the same power to motor it will take more current ie more than 20 amps.

Is This Answer Correct ?    2 Yes 3 No

Question { 4927 }

what will happen if neutal in AC ckt will get open


Answer

if the circuit is 3 ph the load beyond the neutral come across tow line (ie;440 v instead of 230 v) then the low wattage equipments will damage,high wattage equipment can withstand the high volt

Is This Answer Correct ?    6 Yes 1 No

Question { 8463 }

A resistor,inductor and capacitor are connected in series
respectively.Voltage across resistor is 40v,across inductor is
70v,across capacitor is 100v.Then what is the total voltage
applied across the elements?


Answer

210 v

Is This Answer Correct ?    2 Yes 3 No

Question { NTPC, 26159 }

how much load should be given on 5 mva transformer


Answer

Transformer have an interesting characteristics ie
You can Load the transformer around 20 % of Full load to
around 120% of full load without any problems(At that time
efficiency lie between 75 to 95 %).But maximum
efficiency will give when copper loss equal to core loss that
is around 80 to 85 % of full load.just see load vs efficiency
curve, then u ll b more clear.

Is This Answer Correct ?    51 Yes 10 No