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Line Wire
When we touch the line wire or supply wire we get shock. What is that? Is it voltage or current or something else?
Harish P. Girhe
- Jan 14th, 2011
Voltage is responsible for electric shock. In house wiring only 5 or at least 10A current flows but potential diff. of 230V get disturb our nervus system. Human body(dry) can sences above 80volt without any danger.(Not every time)
_punjabi_
- Aug 29th, 2010
When you happen to touch the live part of the supply, then your body acts as a part of the circuit and of the Supply system is not grounded and if equivalent resistance of your body is less than that ...
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Wattmeter Circuit
Why pressure coil is named so in wattmeter circuit?
Harish P. Girhe
- Jan 4th, 2011
Current & voltage both requires for utilisation. Current depents on device for its energirising. Each individual device reqiures currents for its own working. But voltage is applied across device term...
prabhat.gaurav
- Dec 8th, 2009
As pressure in pneumatic sysytem is analogaus to voltage that's why the coil connected to supply voltage in wattmeter is called pressure coil.
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Dielectric Strength
What is dielectric strength?
Harish P. Girhe
- Jan 4th, 2011
Material can be conductive or non-conductive. It depends on its di-electric property of that material. Di-electric means property of an material to oppose flow of electrical current. For better condu...
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AC Generator
To induce EMF, either field has to rotate or rotor has to rotate. In Alternator, AC supply is given to the armature to produce rotating magnetic field. The rotor is rotated by the prime mover. Then how will EMF be produced in an alternator. Explain the working principle of alternator in detail?
manilal.r
- Jan 2nd, 2011
Like a DC generator, an alternator also has an armature winding, but there is one importent difference between two, in a DC generator, the armature winding placed on rotor in order to convert AC? to ...
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DG Set Tripp
What will you do when D.G. set gets tripped?
Raman Jain
- Jan 3rd, 2011
First see at what indications D.G set get tripped. Find the cause and rectify . Than again start the DG set.
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Power Plant
What is the processing of power plant and what are the equipment used for coal handling power plant?
Raman Jain
- Jan 3rd, 2011
There are various equipments used in the Coal Handling Plants :1. Wagon Tipplers : to unload the coal wagons2. Stacker - Reclaimers : stack and reclaim the coal in/from stock yard.3. Conveyor Belts : ...
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Reactive Power
How much reactive power does a generator of rating 3.5MW generate?
Raman Jain
- Jan 3rd, 2011
The reactive power , Generator can supply, can be determined by the Capabilty Curve of the Generator , supplied by the manufracturer.This is a design criterion.
raviiisc
- Sep 8th, 2010
Generally the Alternator or Generator is rated in MVA format rather than MW format.The reactive power supplied by the generator is then decided.I think the questioner thinking about the ratings provid...
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Motor Vibration
What can be the possible causes of Vibration in HT motors?
Raman Jain
- Jan 2nd, 2011
Vibrations in HT Motors may be due to several reasons :1. Mis-alignment 2. Worn Bearing3. Loose foundation bolts.4. Unbalance rotor etc.
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Potential Transformers Applications
What are the applications of potential transformers other than metering and under voltage protection?
Raman Jain
- Dec 29th, 2010
There are numerous applications of Potential Transformers .1. For Metering Purpose.2. Required for Synchronisation of Feeders / Generator with Grid.3. For Feed back of AVR.4. Distance Protection of fe...
ripago
- Nov 28th, 2010
1. Over/Under Freq. Protection2. Syncrhonizing Generator to Grid.3. If you don't have spare of PMG then you can use this PT for AC Power supply to the excitation Unit of your own Genarator.
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Is it possible for a feedback surge to travel over a wireless connection? Would the answer be different in a vacuum?
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Series Connection
If 100w & 50w bulb connect in series and if we supply 440v then what happen, which one glow first?
veerateja
- Dec 17th, 2010
The two bulbs will glow at a time bcoz the ckt should close the path through the second bulb also mean while the electricity(electron) speed is nearley equal to light speed.
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Transformer induced emf
Is the transformer induced emf E1 and E2 in same phase or in opposite phase? Explain Why?
ripago
- Nov 28th, 2010
It depends on winding direction between primary and secondary coil ( this is so called polarity). If winding direction of primary and secondary coil same, then E1 would be in phase with E2. but if opposite then EMF also would be opposite (180 deg.)
kirank_239
- Mar 31st, 2009
The voltage induced in the primary and secondary windings is due to the same flux i.e., the primary flux. Hence E1 and E2 are in same phase
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Power Lines Protection
Why the 1st zone of protection relay is 90% not 100%?
ashokumarrk
- Nov 14th, 2010
Zone-1 protection is 80% in (NTPC, POWER GRID, NPCIL, NHPC, BBMB....) bcz we have consider the errors in CT, PT and also the line length. Datas provided should be same as the actual, but it wont. In order to compensate all these Zone-1 protection is 80%
pradipsabar2009
- Jul 29th, 2010
If we consider the 100%, 100% in the sense there is another CB present there. so there is a dilemma which CB should operate first. Hence the first zone of protection is never 100%
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Transformer
What happens to the power factor of a transformer when the input voltage exceeds the rated voltage? Will it increase or decrease? Give explanation.
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Phase Usage
Why and when we use single phase and three phase?
raviiisc
- Oct 31st, 2010
This is the most common question.Whenever we are dealing with large quantity of power we use the Three phase system rather than the single phase system. The cause is the cost of eqipment is more....
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Inverter and UPS
What is the difference between INVERTER and UPS?
prafulla patil
- Oct 29th, 2010
The main difference between Inverter and UPS is switching time.Inverter switching time is inverter switching time is more than UPS , inverter Takes approx 500 millisecond to switch , that’s why ...
full61
- Apr 15th, 2010
Inverter converts only DC to AC but UPS converts AC to DC and then store it after that it convert DC to AC.
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Induction Motor
In single phase induction motor, what is phase? what is induction? Why only this motor used in fans?
guntur.srikanth
- Sep 30th, 2010
Mainly the induction motor works with mutual induction principle that is why we are using them in fans
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Quality Factor
What is the importance of quality factor in resonance?
thakur.rajesh.ranjan
- Sep 27th, 2010
Sinusoidally driven resonators having high quality factor resonates with greater amplitudes but have a smaller range of frequencies around that frequency for which they resonates. Thus a high Q (quali...
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Water Level Sensor
What sensor is used to measure the level of water in a tank?
thakur.rajesh.ranjan
- Sep 25th, 2010
A small rubber ball, we generally use in our dewatering sump for water level sensor. This gives command mechanically to level switch.
ravs42
- Aug 6th, 2010
A simple mechanical model for water level indicator includes a float(rubber ball) providing? a mechanical link to the indicator i.e. d output. When the water level rises the float due to it's light weight raises up and via the link the pointer will move to display the required output.
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Reactive Power
What is mean by reactive power? How it is generated?
Sreebai
- Sep 21st, 2010
Reactive power is the power required to transmit the active power. The reactive power is like an envelop,that is used to send a letter. Without this we cant send the active power and it cant be too hi...
SURAJTHEGREAT
- Mar 3rd, 2009
We know reactance (hypothetical resistance) which reduce the supply voltage by opposite flowing induced emf. This power loss due to reactance is known as reactive power. This power is not useful power. It is a waste. However it is useful in determining the phase angle.
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