What is shape of the coils used in a transformer ? choose the correct one from the bracket (rectangular,oval,circular,cylindrical ) & justify it with detail reason.

Is transformer a machine ?choose the correct one from the bracket (yes/no) & justify it with detail reason.

manikandan.l

• Jul 18th, 2014

Rectangular

AlHussein Abdallah

 Profile Answers by AlHussein Abdallah Questions by AlHussein Abdallah

• Jul 17th, 2014

Star connected rotor of induction motor has a standstill impedance of (0.4+4j)ohm per phase and rheostat impedance per phase is (6+2j)ohm. The motor has induced voltage of 80v between slip-rings at st...

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If we take the winding displacement as 180 degrees in 2 phase winding what will happen?

Himang

• Jun 9th, 2014

Non uniform torque will be produced which would make the operation noisy.

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Though transformer consist winding which usually cause reactive power change in both generator and motor but it wont affect reactive power passing through transformer why?

Dnyanesh

• Jun 7th, 2014

In rotating motor, power factor can not be maintain at unity bcz these all are inductive, but in case of transformer, we can maintain the power factored at unity, and whenever pf is unity, there will be zero reactive power

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ilamurugan

• May 4th, 2014

Both source becomes single source of higher capacity and at the time of syn only entities are taken for reference. Once syn done its.single.source so need of current flow within that source

atul sudhakar

• May 2nd, 2014

In that case ,current flows due to the difference in load angle. synchronizing the system increases the efficiency of the power flow

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atul sudhakar

• May 2nd, 2014

In simple words, the power which is used to setup a magnetic field for the machine

jagadish

• Sep 21st, 2013

Reactive power is the virtual oscillating power in the power system that enables active power to do the work in the system.So it is necessary for the power system.

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atul sudhakar

• May 2nd, 2014

Increased frequency causes increased losses and we yet don't have the technology to have the strong foundation to keep machine running at that high frequency

ripplenwinder

 Profile Answers by ripplenwinder Questions by ripplenwinder

• Dec 10th, 2013

In power transmission it cant due to EFIENCY and COST. The higher the frequency the more it is essentialy a direct current! so 100HZ has more power loss due increased current lower peak voltages at th...

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what happens when we apply ac voltage to a DC motor (nothing but if any DC motor)?

atul sudhakar

• May 2nd, 2014

Depends if it is dc shunt motor it will not work but if its a dc series motor it might

Shuvendu Das

• Nov 8th, 2013

Excess heat would be produced due to hysteresis and eddy current loss

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Why 440 volt 3 -phase power supply is showing neutral as phase and phase as no supply? As still the power is supplied to the load and its working?

rajkiran

• Apr 9th, 2014

In unbalanced loads, i.e., one phase has more load compared to rest of two phases. at that time the loaded phase voltage is low compared to rest of two phases. the difference in voltage is shown at neutral.

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Will u please give the formula, for selection of cable sizing (both Copper and Aluminium) depend upon the electrical loads...

ENGR.MUHAMMAD YOUNAS KHAN

• Mar 24th, 2014

CABLE SIZING FORMULA:-2 *L * I/(K*Vd) ...............FOR SINGLE PHASE LEGEND:- I :- LOAD CURRENT =160 AMPS L :- LENGTH OF THE CABLE = 200 METERS K :- CONDUCTIVITY OF COPPER = 58 AND CONDUCTIVITY OF...

mahmoudp1

 Profile Answers by mahmoudp1 Questions by mahmoudp1

• May 3rd, 2012

It depends on a lot of factors like current density for mm^2 temperature is the cable on cable trays or buried or inclosed in PVC is that a 3 phase cable multicore or what and also depends on the voltage but in general making a current density 2 A/mm^2 for copper for simple applications is good.

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Why armature control is used, not the field control for DC motors?What is the drawbacks in field control method?

chiragmistry

• Mar 14th, 2014

In case of the dc motor the armature control mathod is used blow the based the motor is run below the based speed Because,above based speed motor react as generator.

AHORDZI ERIC

• Nov 20th, 2013

What is ammeture reation

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chiragmistry

• Mar 14th, 2014

Its very simple connect the capacitor and inductor in series.

abhinay

• Sep 20th, 2013

In our tutorials about Electromagnetism, we saw how an electric current flowing through a conductor can be used to generate a magnetic field around itself, and also if a single wire conductor is moved...

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What is neutral transformer?

Alok Behera

• Feb 12th, 2014

If the earthing transformer on the Delta Side is outsides the Zone of protection the Earth Fault(E/F)in the delta system outside Current Transformer(CT) locations would produce current distributions a...

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What is the difference of h.t and l.t. cables ?

RAHUL LOHIYA

• Feb 5th, 2014

GENRETION TRANSMISSION DISTRIBUSTION

sanket

• Oct 2nd, 2013

L.T. means low tension use for below 1000 volts normally pvc cables
H.T. means high tension cable use for more then 1000 volts normally are xlpe shielded cables

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What is the difference between a capacitor and a condensor?

ripplenwinder

 Profile Answers by ripplenwinder Questions by ripplenwinder

• Dec 11th, 2013

There is no difference with the exception or semantics and argument. Tesla use to call a capacitor a condenser we now call a condenser a capacitor. Schematics symbol for both are the same!

Pruthvi

• Oct 21st, 2013

Main diff. b/w Condensers and capacitors are
i. Condensers are rotating while capacitors are static
ii.Smooth flow in KVAR can be obtained through condensers while it cannot be obtained through switching capacitor banks.

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In the car alternator is a 3 phase generator and rectified instead of using dc generator.

Why ac alternator is better than dc generator in any car?

ripplenwinder

 Profile Answers by ripplenwinder Questions by ripplenwinder

• Dec 11th, 2013

No! 3 phase has no rectifier or voltage regulator a car alternator does. DC the voltage and current are suppose to be 180 degrees out of phase from one another or so most people think. Current can go ...

suryatejreddy

 Profile Answers by suryatejreddy Questions by suryatejreddy

• Apr 12th, 2013

DC generator although produces a.c,it must be converted to d.c by rectifiers in order to store in the batteries and to it supply must be dc,so in cars instead dc generators alternators are used.

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• Dec 11th, 2013

Polarization is a complex subject? But is easiest understood to me a position, location, direction, depth and etc. from a center point of refrence it is easiest understood by ceating a sphere around t...

Yasser Ali

 Profile Answers by Yasser Ali Questions by Yasser Ali

• Nov 1st, 2013

Polarity may refer to: In science: Polarity (mutual inductance) Polarity (physics), a physical alignment of atoms Cell polarity, differences in the shape, structure, and function of cells Chemical po...

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prove :

average power = instantaneous power

in 3 phase induction motor

ripplenwinder

 Profile Answers by ripplenwinder Questions by ripplenwinder

• Dec 11th, 2013

We can define the 3-phase voltages as: 1) v1 = Vp x sin(u); 2) v2 = Vp x sin(u +120); 3) v3 = Vp x sin(u -120) 4) vn^2 = v1^2 + v2^2 +v3^2 = K 5) sin(u +/- v) = sin(u)cos(v) +/- cos(u)sin(v); 6) sin^...

ripplenwinder

 Profile Answers by ripplenwinder Questions by ripplenwinder

• Dec 11th, 2013

Good guestion Ill get back to you on that one.

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tanweer salim

• Nov 21st, 2013

Ups uninterruptible power supply

nazmul haque

• Jul 16th, 2011

Uninterrupted Power Supply...............

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Shivam Jha

• Oct 16th, 2013

Regulator is a device used to vary the supply voltage according to our use.Where as stabilizer is a static device which is used to maintain constant supply voltage

abhisek kundu

• Sep 18th, 2013

Regualtor is for d.c application & stabilizer is for a.c application

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ULAGANATHAN

• Oct 3rd, 2013

Voltage exist only for a closed circuit whereas emf exist for a open circuit.

vehvariya

• Sep 23rd, 2013

Voltage is the potential difference applied between the two terminals, where as EMF is the electromotive force induced in the conductor due to the voltage because of the floe of the current.

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