Answer / durgak

To know the need of Transformer we must know what
Transformer does. It is a static device which transforms
the voltage (electromagnetically).In certain cases the
required voltage of a system needs to be increased or
decreased,so in those cases a step up/ step down
transformer is a must required.

Secondly it may be called as a protection device to the
electrical network. At times due to heavy electrical faults
it trips by keeping the main supply system healthy.

To know more in detail about Transformers please refer Book
on Electrical Machines...by M.G.Say......

Answer / ramee20374

1.We need Transformer to step up and step down voltage
level w/o having much loss.
2.Step up voltage was used to Transmit the power to very
long distance w/o higher transmission loss.
3. Because of Static device it operating effiecincy is 98%
compare to any electrical device.
4. Easy control & voltage adjustment.

Answer / nagarjuna

we use transformers for step up and step down the voltage
according to our needs.

Answer / sunil guru

transformer's are used for various main function....
1.To step-up
2.To step-down
3.for isolating the circuit.
4.for protection.
5.for measurement of voltage.
6.for control purpose..

Answer / pavan

Our systems or some machinery needs certain amount of
voltage so that by using transformer we can stepup/stepdown
the voltage what our system needs.

Answer / rahul

all the answers above are correct...

Step up, step down
protect the main connection
Variable transformer- to reduce the starting load.
Isolation transformer - to prevent the machines from getting damaged from spikes as transformers filter them.

all these answers must be answered simultaneously to describe the transformer completely... & i really dont know which is saying the answers above that of mine are wrong.. they are right but are partially answered

Answer / deepak

we need transformer because ,
when current travels certain distance ,
it looses some energy in form of heat...
so in order to preserve it it is used for stepup and stepdown function....

Answer / rashmi.c

to step up and step down the voltage...

Answer / joel kern

All the above answer are correct to the true function of a transformer.

However, the main reason to "why" we use transformers is so that we can keep those big, smelly, dirty, ugly power plants as far away from our homes and workplaces (unless you work at a power plant) as possible. Without transformers, you would have to generate all the power you need at the source.

This Nissan Leaf commercial, though exaggerated, does a pretty good depiction of the what world would be like w/o transformers:

http://www.youtube.com/watch?v=N7K_hWuPwv0

Add to the gas any fossil fuel or renewable energy and you will get the picture. Not that all power plants are ugly or dirty, but transformers (no matter the size) allow us to generate power in one place and consume it in another.

Answer / akki

A transformer is a static device used to step up or step down the voltage depending on the number of turns of primary and secondary coils.its also is used to isolate the circuit from direct AC mains power supply.

How open delta used for protection?

4 Answers  

What is the diff. between two phase & three phase supply.

7 Answers   Crompton Greaves,

Based on CPI/CGPA they shortlist the candidates & than directly start Interview so there is no Written Exam or GD Only PI.Interview held @ MNNIT , ALLAHABAD On-Campus on 6th,Aug, 2007 & the Questions asked to me by Interview Board ( 4 People) are from HR/SummerTraining/BTP/Subject-core, POWER SYSTEM & MACHINE. time duration of I/V is about 15-20 Minutes. HR- Q.1 Name,hobbies & About family background ? Q2.What u know abt NTPC ?? Q3.Why u want to choose NTPC as ur Carrier's starting i.e power sector not any other Oragnisation or sector ?? Techincal Questions- Q1.What is the reason for transformer Noise ?? Q2.Which material is used for making Transformer oil & How u measure its dielectric strength & Name the test ? Q.3 Which Machine u will prefer 2 use if flammble gases are coming out at a place & why ?? Q4.What is relation b/w Transmission Lines & Communication Lines ? Q5.What is the maximum capacity Synchronus Machine & total powerGeneration in our country ? Q.6 In india Power generation is at 50Hz while in America its 60 hz ,why so ?? Advantage or disadvantage ?? Q.7 Maximum Generation Voltage in india ? Q8. What is the Voltage regulation & why its required n how much is permissible ? & causes of voltage variation ?? Q.9 Why electric shock is feel ?? n in a Electric Train why we didnt feel that ? Q.10 Have u seen/ experience of any power plant/ industry related to the power sector ? so these are the questions which not too diffcult i think was asked to me.

6 Answers   NTPC,

what is SWA type of cable?????

4 Answers  

we use 400/5A ct and 35/roor3KV,/0.1/root3KV,0.1/root3KV pt ratio. What is the multiple factor of this meter.

0 Answers   ABB,

In CTs tan delta point should be earthed , what is the reason behind it?

0 Answers  

how to calculate overall efficiency of diesel generator set? give us a formula with an example.

2 Answers  

How does solar power system work?

1 Answers  

Fault current shall be part of tech specs of power cable or not?.

1 Answers   DAE,

Why material of brush is carbon in motors why not other material.

5 Answers   NTPC,

1.Why we use choke?If we use for high starting voltage then different type choke gives different voltage. Is it correct?

2 Answers   Dalkia, Luminous,

what is the difference between OSR and BUCHHOLZ relay of transformer?

1 Answers   Bhushan Power Steel,