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CT ratio
Can anybody tell me that how to choose CT for a specific load? I have a 200kw induction motor, which ratio CT should be installed? Is there a formula or calculation that determines the CT ratio for a load?
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What is watt?
bharath
- Sep 8th, 2011
It is the unit of power and used to specify the rate of electrical energy is dissipated.
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What is the use of control panels in transmission systems?
RAVI KUMAR
- Sep 14th, 2011
control panels are used in substations ... use is for monitoring of power system... controlling of real and reactive power flow is also done from the control panel... in case of occurrence of fault...
rahulr30
- Jun 8th, 2008
Control Panels literally help in controlling power supplied. It helps in protection and cntrols the various CBs and other protection Equipments. It hac Current relays etc to sense the current.I also helps to pinpoint the location of faults in feeders.
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DG Set
What do you do if your DG Set is not taking load?
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What is the action in conductors, electrons or atoms when rotating magnetic field is in contact?
When a conductor placed in a rotating magnetic field, what is the action inside the conductor (basis of electrons /charge) ?
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Reactive Power
Why the reactive componet is generated in power system?
bittu123
- Nov 10th, 2011
If alternator is Overexcited, it will deliver reactive power with lagging current while in Underexcited, it absorb reactive power with leading curreent But, it always(under or over-excited) deliver ...
Sagar_upadhyay
- Sep 25th, 2011
In most of the power stations, the generation takes place by synchronous generators. The synchronous generators are doubly excited in nature. When the rotor is fed with a DC field, power is generated....
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LT Panels
What are the various types of LT panels? Name them.
Nisar shaikh
- Sep 25th, 2011
Properly Earthing and Bus bar side some Gape and properly insulation
Total load Distribution system
Power factor properly Automation system
Properly switch system -
Lightning Arrester
what is lightning Arrester? what the use of this in substations?
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Track gauge
What is the purpose of track gauge used in transformers?
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Is possible to increase the voltage without using transformer? why?
bittu123
- Nov 7th, 2011
I went through all answer, seems all are correct.... But lemme be more precise.. Except transformer..... 1. CHOPER: It is said to be DC equivalent of AC transformer, so can be used to increase and d...
santosh
- Nov 7th, 2011
We can step up and down dc voltage using chopper circuit
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Earth Fault
What is the technical difference between earth fault and earth lekage relays ?
bittu123
- Nov 8th, 2011
Earth fault : If live wire gets touched to the earth, heavy current start flowing through this wrong path, causing short circuit and considered to be a kind of fault. Earth leakage relay: Instrument ...
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Power Measurement
Why current coil and pressure coil of wattmeter is connected in different phases for reactive power meaurement?
bittu123
- Nov 8th, 2011
You have to draw a phasor diagram. then U will get it easily. Draw Vr, Vy, Vb with 120 degree displacement. Now draw Ir leading(lagging) Vr by some angle, Say 0. and Iy displaced 120 degree to Ir, sa...
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American Distribution System
What is the difference between American and Indian distribution system? Which one is better and why?
bittu123
- Nov 8th, 2011
AMERICAN : frequency 60Hz House hold voltage: 120v and 240v Split phase 3 wire service INDIA: frequency 50 Hz House hold voltage : 230v and 4...
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Phase Advancer
Why Phase Advancer is not used in below 200kva machine?
bittu123
- Nov 8th, 2011
During starting or low load condition IM works on very lagging current which results in taking high current. This sudden high current may creats transient in power system, which is undesirable. Phase ...
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PNPN Thyristor
Why PNPN is used as thyristor NPNP is not used?
bittu123
- Nov 8th, 2011
Funny, what differences PNPN & NPNP makes? If you have PNPN thyristor, its kept on table, U are seeing PNPN, right? Now, keep its back in front, whats this now? NPNP......isn't that? its not transist...
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Capacitor Connection
Why the capacitors are connected in delta? What advantage it having than star connection?
bittu123
- Nov 8th, 2011
Prime reason : Delta connection will give 3 times more reactive power(kVARs) than star connection.
there are few more reason....
1. less triplen harmonic
2. less heat loss, since current is I/1.732 where I will be the current star connection pr phase
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Electrostatic Power
Is it possible to generate electrostatic power? If yes, how?
bittu123
- Nov 8th, 2011
Yes electrostatic power generation is possible as VAN DE GRAAFF generator is best example of it. But this is not economical and usable for general purpose, So, Electrostatic power generation is not pr...
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Electrical Wiring and Circuit Questions
1)How much current can a 3-1/2 core 100 mm wire carry?
2)What is the latest generation of circuit breakers called?
3)What are the special cables required for explosion proof wiring?
4)What are the different types of soft starters for large motors?
5)What is the similarity and what is the difference between relays and PLC?bittu123
- Nov 8th, 2011
I am answering few of them................. 1)How much current can a 3-1/2 core 100 mm wire carry? - It depends on "what conductor(aluminium, copper or else) you are using" and "whether it is insula...
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Contactors in circuits
Why we use contactors in ckts....how many types of contactors are there.. how we select the contactor for in ckt for its operation
bittu123
- Nov 8th, 2011
Contactor is basically a large relay kind of thing which is used to switch large amount of power. It has multiple contacts and all contacts can be switched together. all multiple contacts are controll...
Electrical Engineering Interview Questions
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