Electrical Machines For successful parallel operation of two single phase transformers, the most essential condition is that their polarities are properly connected percentage impedances are equal KVA ratings are equal turn- ratios are exactly equal polarities are properly connected percentage impedances are equal KVA ratings are equal turn- ratios are exactly equal ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines For a specific open-circuit voltage of a DC generator, the short-circuit electric current will be maximum when it is separately excited. shunt connected. cumulatively compounded. differentially compounded. separately excited. shunt connected. cumulatively compounded. differentially compounded. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A commutator with a diameter of 50 cm rotating at 1000 rpm. For a brush width of 1.5 cm, find the time of commutation in ms. 0.512. 0.649. 0.573. 0.443. 0.512. 0.649. 0.573. 0.443. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If Kh is hysteresis constant, f is supply frequency, Bm maximum flux density in core of transformer, the expression of hysteresis loss in transformer, is given by KhfBm1.6. Khf2Bm1.6. KhfBm3. KhfBm. KhfBm1.6. Khf2Bm1.6. KhfBm3. KhfBm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Consider the following statements regarding dc machines : 1. possible resistance of shunt-field winding is 1 Ω 2. possible resistance of series-field winding is 1 Ω 3. electrographite brushes are used for 230 V, 10 A machines 4. Copper-graphite brushes are used for 230 V, 10 A machines 5. Possible armature-circuit resistance is 1 Ω From these, the correct statements are 2, 4 ,5 2, 3 , 5 1, 4 1, 3, 5 2, 4 ,5 2, 3 , 5 1, 4 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines When flux density is constant in a transformer, hysteresis loss varies as f² V V² f f² V V² f ANSWER DOWNLOAD EXAMIANS APP
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