Rajkamal Sir (Engineers Platform) 📚📚

5. The ratio of primary/secondary voltages is 2:1. The saving in terms of the weight of copper required if an autotransformer is used instead of a two-winding transformer will be

4. A 240 V/120 V, 12 kVA auto-transformer has 96.2% efficiency at full-load and unity power factor. The full-load efficiency at 0.85 pf lagging when connected to a load across 360 V would be

3. A 2000 V/200 V, 20 KVA, two-winding single-phase transformer is reconnected as a step-up auto-transformer having 200 V/2200 V ratings. Then the power rating for the auto transformer will be

2. A 400 V/100 V, 10 KVA two-winding transformer is reconnected as an auto-transformer across a suitable voltage source. What could be the maximum rating of such an arrangement?

1. The kVA Rating of an ordinary 2-winding transformer is increased when connected as an auto-transformer is due to

5. In order to achieve high accuracy, the slide wire of a potentiometer should be

4. Basically a potentiometer is a device for

3. A phase shifting transformer is used in conjunction with

2. To measure a resistance with the help of a potentiometer it is

1. A direct current can be measured by

5. The coal which has highest ash content is: