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RICH DAD POOR DAD BOOK REVIEW

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  RICH  DAD  POOR  DAD  BOOK REVIEW This is amazing book.   • Explodes the myth that you need to earn a high income to become rich • Challenges the belief that your house is an asset • Shows parents why they can't rely on the school system to teach their kids about money • Defines once and for all an asset and a liability • Teaches you what to teach your kids about money for their future financial success It's been nearly 25 years since Robert Kiyosaki’s  Rich Dad Poor Dad  first made waves in the Personal Finance arena. It has since become the #1 Personal Finance book of all time... translated into dozens of languages and sold around the world. Rich Dad Poor Dad  is Robert's story of growing up with two dads — his real father and the father of his best friend, his rich dad — and the ways in which both men shaped his thoughts about money and investing. The book explodes the myth that you need to earn a high income to be rich and explains the difference between working
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What are the construction of Transformer ? Insulating Parts

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 Insulating Parts

Insulation is essential to isolate the live parts inside a transformer from other live parts at different potential or from the grounded parts.
 
The desirable properties of an insulation material are:
  1. High resistivity
  2. High breakdown voltage (breakdown strength)
  3. High dielectric constant (ɛr)
  4. Low dissipation factor (tan 𝛿)
  5. Thermal stability
  6. Chemical stability
  7. Mechanical stability

The different MAJOR insulations in a transformer are:
  1. Between core and LV (press board)
  2. Between LV and HV (impregnated press board, oil)
  3. Between top and bottom of winding and yoke (impregnated press board)
  4. Between HV and tank (impregnated paper, cotton, oil)
  5. Bushings (Porcelain)- used to take out HV and LV coil terminals from inside the tank for external connections to overhead lines.

The different MINOR insulations in a transformer are:
  1. Between conductors (enamel, varnish)
  2. Between turns (impregnated paper, cotton)
  3. Between layers (impregnated paper, cotton, press board)
  4. Between laminations (varnish)
  5. Between joints and connections (varnished tape)


It is obvious that any insulating material used to act as a barrier between two live parts, or between a live parts and a grounded part of an equipment, must not allow any flow of current through it. 
In other words,
The insulation must have very high resistance, i.e., its resistivity must be very high to ensure minimum amount of leakage current through it. Otherwise, Flow of leakage current through the insulation causes power loss, resulting in heating that may finally damage the insulation causing short circuit.

Insulating materials must have the capacity to withstand sufficient voltage stress across it. Otherwise, the insulation material may get punctured at high voltage stresses leading to short circuits faults.

Electric field strength inside the insulation material (parallel plate capacitor configuration) is given by:
E = Q / 4𝜋ɛoɛr (d^2)

The dielectric constant (relative permittivity- ɛr) value is different for different insulating materials:
ɛr (air) =1
ɛr (oil) ≈ 2
ɛr (paper) ≈ 4 - 5
ɛr (pure water) ≈ 80

For better insulating material as the dielectric strength ɛr goes up, the electric field strength reduces and hence chances of insulation breakdown are less. 
A better insulation (high ɛr) will require less distance between the two electrodes, thereby reducing size of the whole system.

The nature of insulation to be used depends largely on the type of transformer. The heat generated due to various losses in the core and winding of a transformer need to be dissipated to the atmosphere, otherwise the transformer life gets drastically reduced. There are two types of transformer on the basis of cooling method used.

  1. Dry type                                2. Oil Cooled
  • Air Cooled
  • Molded


Related topics>>>Magnetic Parts

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