A step up transformer increases

• (A) frequency

• (B) current

• (C) voltage

• (D) power

Natural oil cooling is used for transformers upto a rating of

• (A) 250 kVA

• (B) 500 kVA

• (C) 1000 kVA

• (D) 3000 kVA

The chemical used in breather is

• (A) silica gel

• (B) sodium chloride

• (C) silica sand

• (D) asbestos fibre

Transformer cores are built up from laminations rather than from solid metal so that

• (A) eddy current loss is reduced

• (B) turn ratio is higher than voltage ratio

• (C) oil penetrates the core more easily

• (D) less insulation is required for the windings

In a transformer the energy is conveyed from primary to secondary

• (A) by the flux

• (B) through air

• (C) through cooling coil

• (D) none of the above

The path of a magnetic flux in a transformer should have

• (A) low reluctance

• (B) low resistance

• (C) high resistance

• (D) high reluctance

The chemical used in breather for transformer should have the quality of

• (A) cooling the transformer oil

• (B) cleansing the transformer oil

• (C) absorbing moisture

• (D) ionizing air

Power transformers are generally designed to have maximum efficiency around

• (A) 10% overload

• (B) no-load

• (C) half load

• (D) near full load

Which winding in a transformer has more number of turns?

• (A) primary winding

• (B) secondary winding

• (C) low voltage winding

• (D) high voltage winding

Losses which occur in rotating electric machines and do not occur in transformers are

• copper losses

• hysteresis and eddy current losses

• magnetic losses

• friction and windage losses