1 Answer

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.

Related questions

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 : 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.

Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?

Last Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.

Description : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Last Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

Last Answer : Necessary conditions required to be satisfied in order to ensure successful parallel operation of single phase transformers:  1. Only transformers having the same phase displacement between primary and secondary ... . 7. The phase sequence must be followed strictly on HV and LV side connection.

Description : Explain the series and parallel operation of MOSFET. Which is suitable and why?

Last Answer : Series operation of MOSFET: To increase voltage handling capability MOSFETs are connected in series. When the MOSFETs are connected in series each MOSFET should turn on and turn off ... on and turn off time and transconductance. Each MOSFET should share current equally.  

Description : Also, highlight the problem faced during parallel operation.

Last Answer : Parallel operation of IGBT: Parallel operation of IGBT is done for obtaining high current rating. Paralleling of IGBT reduces conduction losses and thermal stress. IGBT combines the qualities of ... . IGBTs must share losses equally otherwise IGBT may get failure due to thermal differences.

Last Answer : Differentially compound D.C. motors can find applications requiring low starting torque.

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

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

Description : Consider a circuit with three parallel branches connected across a DC supply. What is the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio of 2 : 3 : 4 respectively? A) 2 : 3 : 4 B) 6 : 4 : 3 C) 4 : 3 : 2 D) None of these

Last Answer : Consider a circuit with three parallel branches connected across a DC supply. What is the ratio of the branch currents I1 : I2 : I3 if the branch resistances are in the ratio of 2 : 3 : 4 respectively? A) 2 : 3 : 4 B) 6 : 4 : 3 C) 4 : 3 : 2 D) None of these

Description : Four Quadrant Operation Of DC Motor

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 : The resistance of armature winding depends on (a) length of conductor (b) cross-sectional area of the conductor (c) number of conductors (d) all of the above

Description : The armature of D.C. generator is laminated to (a) reduce the bulk (b) provide the bulk (c) insulate the core (d) reduce eddy current loss

Description : Which of the following could be lamina-proximately the thickness of laminations of a D.C. machine ? (a) 0.005 mm (b) 0.05 mm (c) 0.5 m (d) 5 m

Description : Laminations of core are generally made of (a) case iron (b) carbon (c) silicon steel (d) stainless steel

Description : What is the smallest unit of a compound with the same chemical characteristics?

Last Answer : The molecule is the smallest unit of a compound with the same chemical characteristics.

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 : 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 : In D.C. generators on no-load, the air gap flux distribution in space is flat topped.

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.

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 : Is more power dissipated in series or parallel?

Description : How To Parallel Park ?

Last Answer : How To Parallel Park Every eager driver must know how to parallel park. This is a cinch for expert drivers who've been on the road for years, but if you're a newbie behind the wheel, this can ... good driver must know how to parallel park properly. Learn how to do this, by following these easy tips.

Description : Explain with neat diagram series and parallel magnetic circuits. 

Last Answer : Series magnetic circuit: When different magnetic materials having different lengths, cross sectional areas and permeability are connected one after another, in which same flux is established in different sections, then it is called series ... flux, Φ = Φ1 + Φ2  Path 1: BAFE  Path 2: BACD

Description : A parallel RLC circuit has the node equation Determine v(t) using the phasor method.

Last Answer : A parallel RLC circuit has the node equation Determine v(t) using the phasor method.

Description : Series parallel resistances problem solution

Last Answer : Series parallel resistances problem solution

Description : what is equivalent resistance when four 4 Ohm resistors are connected in i) series ii) parallel

Last Answer : equivalent resistance

Description : Parallel rc circuit

Last Answer : Parallel rc circuit