Recent questions tagged generators

Description : DC GENERATORS MCQ

Last Answer : 101. Wave winding is composed of (a) any even number of conductors (b) any odd number of conductors (c) that even number which is exact multiple of poles + 2 (d) that even number ... increase the field resistance (c) increase the speed of primemover (d) check armature insulation resis¬tance Ans: a

Description : The field coils of D.C. generator are usually made of (a) mica (b) copper (c) cast iron (d) carbon

Last Answer : Ans: b (b) copper

Description : How Generators Work

Last Answer : How Generators Work Generators are devices which produce electricity. They produce electricity by converting mechanical energy from power sources. Examples would be steam, water, wind and gasoline. These ... can also be used for recreational purposes. Examples would be camping, boating or fishing.

Description : Why are generators rated in kVA not in kW ?

Last Answer : Because It's rating of generator kva is apparent power. Kw is active power which we use. And one is kvar reactive power.

Description : Two synchronous generators G1, G2 are operating in parallel and are equally sharing KVAR (Lag) component of load. To shift part of KVAR from G2 to G1, while keeping terminal voltage fixed, the following action must be done

Last Answer : Two synchronous generators G1, G2 are operating in parallel and are equally sharing KVAR (Lag) component of load. To shift part of KVAR from G2 to G1, while keeping terminal voltage fixed, the following action must be done Raise If1 and lower If2

Description : Identify the increasing order of voltage regulation of the following dc generators a same load :  (A) differential compound, shunt and under compound  (B) shunt, differential compound and ... C) under compound, shunt and differential compound  (D) shunt, under compound and differential compound

Last Answer : Identify the increasing order of voltage regulation of the following dc generators a same load : under compound, shunt and differential compound 

Description : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, ... system frequency is (A) 50 Hz (B) 51 Hz (C) 51.25 Hz (D) 51.5 Hz

Last Answer : Two synchronous generators operating in parallel supply a common load of 2.5 MW. The frequency-power characteristics have a common slope of 1 MW/Hz and the no-load frequencies of the generators are 51.5 Hz and 51.0 Hz, respectively. Then the system frequency is 50 Hz

Last Answer : If  equalising bar is connected to the 2 DC generators  the current will be equal in 2 generators irrespective of parallel connection so that we connect equaliser bar

Last Answer : In D.C. generators the polarity of the interpoles is the same as that of the main pole ahead.

Last Answer : For the parallel operation of two or more D.C. compound generators, we should ensure that series fields of all generators should be either on positive side or negative side of the armature.

Last Answer : Compensating windings are used in D.C. generators to neutralise the cross-magnetising effect of the armature reaction.

Last Answer : D.C. generators are connected to the busbars or disconnected from them only under the floating condition to avoid sudden loading of the primemover, to avoid mechanicaljerk to the shaft, to avoid burning of switch contacts.

Last Answer : In D.C. generators, the brushes on commutator remain in contact with conductors which lie under interpolar region.

Last Answer : In D.C. generators, current to the external circuit from armature is given through commutator commutator.

Last Answer : In D.C. generators the pole shoes are fastened to the pole core by counter sunk screws.

Last Answer : D.C. generators are installed near the load centres to reduce line losses.

Last Answer : D.C. generators are normally designed for maximum efficiency around full-load.

Last Answer : Large capacity generators are invariably hydrogen cooled.

Last Answer : Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.

Description : In DC generators lamination core are generally made of?

Last Answer : In DC generators lamination core are generally made of silicon steel.