Question { 9463 }

I want Primary side delta and Sec side Star connection
transformer . but i have received Star - Star
transformer ,shall i use the same transformer by giving the
only 3 ph on Primary side without Neutral connection on the
Starpoint.

Answer

Main reason to use Delta in primary side is to reduce/Eliminate harmonics in primary side whereas star winding will not eliminate.

Question { IBM, 82041 }

what is the function of starter & choke in the tube light
set & how choke give 1000 volts while switching on.

Answer

gases present in the tube light is of such nature that once the gas ionised then it has a tendency to increase continuously accompanied by a fall in the circuit resistance . in order to limit the current to a safe value choke is used .
choke performs two function
1) providing ignition voltage
2) limiting the current

Question { 8318 }

Why Transformer does not work in DC ?

Answer

transform work on the principle of electro magnetic induction which states that when an alternating current applied across the primary winding of transformer then an alternating flux will produced which link to secondary winding of transformer results in emf generated in secondary winding , if secondary winding is closed then a current start flowing .
if we apply dc then flux will also produced but it is not alternating type which is most important condition for the operation of transformer

Question { 2934 }

Lt trivector meter with ring type CT.Spec of meter are
3x240 v, -/5A. Ring ct spec. are 60/5A, line voltage-
IL .66/3.0KV..what is the multiplying factor

Answer

Multiplying factor will be 12