TRANSFORMER BITS

1) Transformer transforms 
   a) frequency
   b) voltage
   c) current
   d) current and voltage

ans d

2) The main purpose of using core in a transformer is to 
   a)  decrease iron losses
   b) prevent eddy current loss
   c) eliminate magnetic hysteresis
   d) decrease reluctance of the conman magnetic circuit

ans d

3) A step up transformer increases 
   a) voltage
   b) current
   c) power
   d) frequency

ans a

4) Ideal transformer 
   a) wingdings have no resistance
   b) core has no losses
   c) core has infinite permeability
   d) all of the above

ans d

5) Transformer core are laminated in order to 
   a) simplify it's construction
   b) minimize eddy current loss
   c) reduce cost
   d) reduce hysteresis loss

ans b

6) Which part of the transformer is subjected to maximum heating.
   a) core
   b) winding
   c) oil
   d) tank

ans b

7) The core of a transformer is made up of 
   a) silicon steel
   b) carbon steel
   c) copper
   d) aluminium

ans a

8) The noise in a transformer is due to 
   a) higher flux density in the core
   b) higher primary voltage
   c) magneto strction
   d) eddy current losses

ans c

9) The chemical used in the breather is 
   a) carbon tetra-chloride
   b) silica sand
   c) silica gel
   d) sodium chloride

ans c

10) Power transformers are designed to have efficiency at
   a) 50% full load
   b) near full load
   c) 90% full load
   d) no-load

ans b