Electrical Machines A commutator in DC machines can 1. provide half-wave rectification 2. Provide full-wave rectification 3. convert ac to dc 4. Convert dc to ac 5. provide controlled full-wave rectification From these, the correct answer is 2, 3, 4 2, 3 ,5 2, 3, 4, 5 1, 2, 3 2, 3, 4 2, 3 ,5 2, 3, 4, 5 1, 2, 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Cross magnetization effects which of the following? reduction in main field flux both 2 and 3 commutation reduces the terminal voltage reduction in main field flux both 2 and 3 commutation reduces the terminal voltage ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two synchronous generators operating in parallel 200 MW and 400 MW respectively. The drooping characteristics of their governors are identical as 4% from no load to full load. Consider the governors operating at 50Hz on no load. How will the machine share, if the load is 600 MW? generator 1 gets over load generator 2 gets over load 230.7 MW and 369.23 MW respectively 200 MW and 400MW respectively generator 1 gets over load generator 2 gets over load 230.7 MW and 369.23 MW respectively 200 MW and 400MW respectively ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The change in speed of a DC generator due to increased load is corrected by increasing input power of the prime mover. increasing terminal voltage. increasing armature resistance. increasing armature cooling. increasing input power of the prime mover. increasing terminal voltage. increasing armature resistance. increasing armature cooling. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding connection must be reversed the armature connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply the field winding connection must be reversed the armature connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Lap winding is prefered for which type of machines? low current and low voltage high current and low voltage low current and high voltage high current and high voltage low current and low voltage high current and low voltage low current and high voltage high current and high voltage ANSWER DOWNLOAD EXAMIANS APP
EXAMIANS