No-load current in a transformer________________?
(A) lags behind the voltage by about 75°
(B) leads the voltage by about 75°
(C) lags behind the voltage by about 15°
(D) leads the voltage by about 15°
No-load current of a transformer has_____________?
(A) has high magnitude and low power factor
(B) has high magnitude and high power factor
(C) has small magnitude and high power factor
(D) has small magnitude and low power factor
Transformer breaths in when_______________?
(A) load on it increases
(B) load on it decreases
(C) load remains constant
(D) none of the above
The maximum efficiency of a distribution transformer is____________?
(A) at no load
(B) at 50% full load
(C) at 80% full load
(D) at full load
Power transformers are designed to have maximum efficiency at___________?
(A) nearly full load
(B) 70% full load
(C) 50% full load
(D) no load
Natural oil cooling is used for transformers up to a rating of____________?
(A) 3000 kVA
(B) 1000 kVA
(C) 500 kVA
(D) 250 kVA
In the transformer the function of a conservator is to_______________?
(A) provide fresh air for cooling the transformer
(B) supply cooling oil to transformer in time of need
(C) protect the transformer from damage when oil expends due to heating
(D) none of the above
In a transformer routine efficiency depends upon_____________?
(A) supply frequency
(B) load current
(C) power factor of load
(D) both
The no load current in a transformer lags behind the applied voltage by an angle of about_____________?
(A) 180°
(B) 120″
(C) 90°
(D) 75°
A common method of cooling a power transformer is_______________?
(A) natural air cooling
(B) air blast cooling
(C) oil cooling
(D) any of the above