A1. When ferromagnetic transformer core is magnetised, the core length along the alternating flux increases and decreases alternately,with the corresponding increase and decrease of its cross section.This phenomenon is called magnetostriction.As the steel laminations change there dimensions alternately, the ferromagnetic core vibrates and a hummng sound is produced.Degree of humming sound depends on the flux density of the core.Greater the core flux density,greater is the tendency of hmmming in transformers.
Joints in the core are also responsible for humming noise though to a lesser degree.
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Q2. Which is the oil used in transformers?What is the function of transformer oil?
A2.Transformer oil, is usually a highly refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties.
Functions
*For cooling of transformer.
*provides part of the electrical insulation between internal live parts.
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Q3. What is a CT?What is a PT?
A3. The instrument potential transformer (PT) steps down voltage of a circuit to a low value that can be effectively and safely used for operation of instruments such as ammeters, voltmeters, wattmeters, and relays used for various protective purposes.
The instrument current transformer (CT) steps down the current of a circuit to a lower value and is used in the same types of equipment as a potential transformer.
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Done for the day.
Bye for now
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