Answer / k.prakashchandra

AC does not have fixed polarities

Answer / k.prakashchandra

Dc is not applied continuously. It is just touch and go, to
create momentary flux.

Answer / raj

then how we are using dc on test ..dc wont step up or step
down.., hw dc is craeting current that was shown in galvano
meter . please explain briefly..?

Answer / er dhananjay kumar

Actually in dc genertae constant flux. When we puch on buttons the contant have to travel from one side of ct (p1) to another side of ct (p2) and in this traveling. The flux is cut by ct winding all this event exist for micro second and this will induce a little potential across secondary side and in unidirectional that's why meter sow a little deflection

Answer / raghavendran.r

I think for Polarity testing AC is being used in power transformers.Let me explain the circuit for the same .Keep the secondary side open.But short one of the terminals of the secondary side with the primary side, so that the primary current flows through the secondary.Now adjust the primary voltage using variac and note down the secondary voltage.If primary voltage is greater than secondary then the polarities are different.
If secondary voltage is more than primary then the polarities are same.
This is how polarity is tested in power transformers and Motors.
The same may apply to CT also.

Answer / gopi

IN AC LOSSES HIGH. BUT DC LOSSES IS LOW

how could we findout the lightning arrester failed or not in live circuit? Is there any instrument to measure the high voltage at the time of sky lighting?

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