Why the transmitted voltage is multiple of 11 like 11, 22, 33, 132 etc? Is their any technical reason for that?

NIMMALA RAKESH

• Mar 28th, 2012

The transmission voltages will be the multiples of 11 i.e. 11kv, 22kv, 33kv,etc., because from the transformer equation we have 4.44*f*n*phi where f is the frequency of ac input , n is the no. of tur...

veeru

• Mar 27th, 2012

The form factor of ac wave form is 1.1 so the voltage is multiple of this

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It is compulsory an magnetic field to produce an current?

SHASHI

• Mar 24th, 2012

NO, ONLY WHEN THE MAGNETIC FLUX LINKED WITH A SURFACE CHANGES CURRENT IS PRODUCED,i.e when the body or magnetic lines are moving.

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What causes transformer humming?

Krishna Kant Gupta

• Mar 13th, 2012

Humming sound in the transformer is due to the stray losses in the transformer due to the leakage flux.this flux produce eddy currents in the nearby conductive areas.The humming sound is the result of...

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 9th, 2011

Humming sound caused by magnetostriction phenomenon. Magnetostriction is change in physical dimension of material because of change in magnetic field.

Since, there is varying magnetic field in transformer causes vibration of core in gap available due to bad insulation. and starts soud hum

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Calculate the length and the distance coved by the lightening arrestor to be installed above 20 feet height industrial building.

Krishna Kant Gupta

• Mar 13th, 2012

Lightning arrestors or lightning rods are used to arrest the lightning surges.This is based on Rolling sphere method according to the Type of protection class you are providing.Rolling sphere radius of 30M or 45M can be used.

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Explain the transformer principle in terms of induced e.m.f. resulting from changing flux linkages?

Krishna Kant Gupta

• Mar 13th, 2012

when a voltage is applied in the primary winding it sets up a primary current which sets up a M.M.F which links both the primary winding and the secondary winding,this m.m.f produces a induced e.m.f ...

Bijendra singh

• Feb 14th, 2012

Transformer basically works on principal of MUTUAL INDUCTION.

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What are high pass filter and low pass filter?

anilsabaji

• Mar 11th, 2012

Read it as High Frequency Pass filter and Low Frequency Pass Filter. You have the answer

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Ahmed Mohsen Fayed

• Feb 27th, 2012

Condenser (heat transfer), a device or unit used to condense vapor into liquid
A capacitor (formerly known as condenser) used to store energy in an electric field.Capacitors are widely used in electronic circuits for blocking direct current while allowing alternating current to pass.

Mannik

• Feb 26th, 2012

Condensor is device which convert the air into water. and capacitor is used to store the electrical charge as potential difference applied on it.

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I have installed 3 Phase Compressor(Condensing Unit) and 1 Phase Evaporator(Fan).

In this 3 Phase Compressor requires Three Phase Supply and not Neutral (which is connected to DOL starter connected) and i want to take power supply for Fan which has phase and Neutral. Whether can i loop phase from the motor and Neutral from the Control Panel. Please tell me its correct or not.

myid123dvg

• Feb 27th, 2012

Yes you can. Make sure your single phase load doesn't get any ground fault. If it happens, control supply trips, tripping the three phase load too.

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Could you elaborate in detail about RJ11 and what does "RJ" and "11" stands for?

ajay

• Feb 22nd, 2012

Rj11 means Registered jack...it is a 6 position modular plug with 2 conductors in the middle........it s a type of communication cable.....

sunil

• Aug 11th, 2011

RJ means Radio Jack (used in US Army terminology).
RJ11 is a kind of telephone socket.

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Briefly explain the difference between the software testing and embedded testing?

I need the brief explanation please provide the details as early as possible

Pramod Jagtap

• Feb 23rd, 2012

The Software testing is mainly done on the software program modules and contains bug identification and its correction. On the other hand Embedded testing can be a Hardware or Software testing. In Har...

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Why transformer does not rotate like induction motor. Inspite both having same principle?

dhananjai

• Feb 3rd, 2012

Actually in 3 phase induction motor the windings are displaced with angle of 120 degree in space that is why a rotating magnetic field is produced while in transformer the windings are concentric rather than displaced

Avishek Pal

• Jan 21st, 2012

Transformer winding is made of concentric winding but the stator winding of induction motor is made of distributed winding over inner periphery. Hence flux in transformer is pulsating in nature and st...

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Why OC test is conducted on low voltage side?

A.santosh

• Jan 27th, 2012

If want to conduct OC test on HV side we need more turns of auto-transformer, as an engineers we should have to decrease the cost required for the test, so normally OC test is conducted on LV side since we need less turns of auto-transformer

sinhasunilk

 Profile Answers by sinhasunilk Questions by sinhasunilk

• Jul 12th, 2010

Voltage injection in LV side is convenient, The cable attached to LV side also need insulation suitable to LV voltage rating. If LV ia in the range of 440V and HV is of the range of 11KV, we may inject voltage in steps also through variac of 440V , Which is not possible if inject voltage in HV side.

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How choke coil and starter gives high voltage(1200v) across tube light to ionise gases in starting while after starting it limits voltage?

tharunp

• Jan 17th, 2012

After supplying 220v, the inductor will be charged. After certain time constant that inductor becomes open circuited. when inductor while charging, suddenly becomes open circuited means it develops hi...

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which is bigger in size AC or DC, of same rating?
As I think DC is right answer but HOW? Explain?

Pasupulati. V. N. Sekhar

• Jan 17th, 2012

The main difference in the size come because of the set up that is present in the DC machines i.e., in order to tap DC voltage generated we require the set up such as Commutator and brush arrangement ...

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Why do some countries have 220V supply while some have 110V and some even have both ?

lif3_h4cK3r

• Jan 13th, 2012

Hello Friend,

The transmission of voltage purely depends on the laws of the country itself.
As Mr. V. N. Shekhar said, it depends on country and there is no technical reason for this adopted system.

Thanks.

Pasupulati. V. N. Sekhar

• Jan 9th, 2012

According to there standard of electrical transmission different sets of voltage and frequencies are chosen. In case of India we choose 220V and 50HZ as our voltage and frequency levels. Where as in some other countries they choose it as 110V and 60HZ

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Phaneee

• Jan 3rd, 2012

Yes, bcoz this meggar has a preliminating voltage statures. so,we can easily check the polarities.

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How to can calculate voltage drop in a cable?

pveee

 Profile Answers by pveee Questions by pveee

• Dec 29th, 2011

Voltage drop in 3 phase circuits is Vd=(1.732xI(Rcos + Xsin)L)/(1000xno.of runs)
I is full load current,
R resistance of the conductor,
x resistance of the conductor,
L length of conductor in meters.

bijumenon

 Profile Answers by bijumenon Questions by bijumenon

• Oct 25th, 2009

According to me this is how the voltage drop in a cable is calculated.If*SQRT(Rf Cos(phi) + Xf sin(phi)) / no. of runswhere....If is the full load currentRf and Xf is the resistance and reactance of the feeder. (Rf = R *L/1000; L= length of the feeder).

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If the capacity of a Transformer is 20/26 then what does 20/26 shows? what is its purpose?

pveee

 Profile Answers by pveee Questions by pveee

• Dec 29th, 2011

If 20/26 is in kva 20kva indicates capacity of transformer under ONAN cooling.

If the capacity is 26kva it is provided with ONAF cooling.

If 20/26 is voltage 20 indicate primary side voltage, 26 indicates secondary voltage, it is stepup transformer.

narasaiah

 Profile Answers by narasaiah Questions by narasaiah

• Nov 7th, 2009

20/26 means 20 primary voltage rating 26 secondary voltage rating

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RAJA.P

• Dec 29th, 2011

The difference between the earth and neutral is 0.8 or below 1

bittu123

 Profile Answers by bittu123 Questions by bittu123

• Nov 8th, 2011

If neutral is grounded, resistance bet earth and neutral will be ideally 0 (zero). or very low depends what conductor is used to connect neutral with earth.

If neutral is not grounded, resistance will depend on atmospheric condition and air density, will be very high, tends to infinity

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Synchronous motor rotates with constant speed but induction motor is not like that, Why?
What is the construction difference between Synchronous motor and Induction Motor?

pveee

 Profile Answers by pveee Questions by pveee

• Dec 26th, 2011

Synchronous motor are constant speed motors where IM are variable speed motors.
Synchronous motor requires special starting set up where as IM are self stared.

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