Answer / dinesh chaudhary

core losses are of two types i.e. hysteresis & eddy current
losse & hysteresis losses are directly proportional to the
frequency & eddy current losses are directly proportional
to the square of the frequency so, the losses will increase
that's why we cant use iron core transformer in high
frequency applications.

Answer / zohaib

iron core losses are directly proportional to frequency , greater frequency means greater iron core losses

Answer / dipankar

i think induced emf~phi.f, where phi=flux, and f=frequency.
to get a certain amount of induced emf for higher frequency
phi should have to be much lower value, and the required
iron core material should be of very high value, as for
lower flux value the flux density should be decreased and
required volume of the core for lower value of flux should
be increased, which is very undesirable for some
application like in airplane etc.Thats why we use air cored
transf. in place of iron cored transf. in high f.

Please give the formula for converting from 1 tr refrigeration to kw.

2 Answers   Bugema University,

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The capacity of the transformer is 20/25 MVA, Ratio is 132/11 KV, Vactor group YNyno. and impedance is 10.07%. As per the calculation the secondary current is 1312.2Amps. The maximum fault current the transformer should sustain is 13.030KA. How many times the transformer should sustain the maximum short circuit current of 13.030KA over a period up 1 Year. The transformer is repaired one & 10 Years old.

1 Answers  

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Hi guys! Plz help me to answer the following questions. 1. What are the types of transmission line energy losses? 2. Why are the VLF are used some types of services? 3. What frequencies are used for reliable beyond the horizon terrestrial communication without repeaters? 4. To permit selection of 1 out 16 equi-probable, what is the number of bitis required? 5. What is the most common modulation used for telegraphy? 6. What is the multiplexing is used to increase the capacity of the optic fiber? Thanks

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Going in for a three phase motor or a single phase motor, what factor should be considered for this? For eg., to pump water to certain height and such domestic applications, which motor is suitable?

1 Answers  

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what will happen if a part of primary winding of a transformer is accidentally short-circuited?

2 Answers  

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What is the Polarisation index value ? (pi value)and simple definition of polarisation index ?

15 Answers   Essar,

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How can we do megger test of cable??

2 Answers  

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what the reson to use phase shift( angle) like (dyn11,Dd5 or Dy0)are usedin power and transsmison line

1 Answers  

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difference between ac and dc generators

4 Answers  

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why ie corona losses in tranmission line

1 Answers  

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Why HT motor is connected in Star?

3 Answers   Equate,

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can we use NPT glands in LT panel

0 Answers  

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