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- A 11000/230 V, 150 KVA, single phase transformer has core loss of 1.4 KW and full load Cu loss 1.6 KW, Find:
- (a) KVA load for maximum efficiency and value of max efficiency at unity power factor,
- (b) efficiency at half full load 0,8 power factor leading.
- Write various necessary conditions for parallel operation of transformer. Two single phase transformer with equal turn ratio have impedance of (0.5+j 3) ohm and (0.6+j10) ohm with respect to secondary. If they operate in parallel, determine how they will share a total load of 100 KW at 0.8 power factor lagging.
- Write advantage and disadvantage of autotransformer. An 11500/2300 V transformer is rated 100 KVA as 2 winding transformer. If the winding are connected in series to form an autotransformer, what will be possible voltage ratio and output and saving of copper.
- Discuss the construction of DC Machine.
- Define Commutation in DC machine and explain its process.