Answer :
Iron losses in a D.C. machine are independent of variations in load.
asked
Mar 20, 2018
by
anonymous
Answer :
The total losses in a well designed D.C. generator of 10 kW will be nearly 500 W.
asked
Mar 20, 2018
by
anonymous
Description : In DC motor iron losses are occurred in?
Answer :
In DC motor iron losses are occurred in the armature.
asked
Mar 26, 2018
by
anonymous
Description : If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be?
Answer :
If residual magnetism is present in a D.C. generator, the induced e.m.f. at zero speed will be zero.
asked
Mar 21, 2018
by
anonymous
Answer :
In a level compounded D.C. generator, full load terminal voltage is equal to no-load terminal voltage.
asked
Mar 21, 2018
by
anonymous
Answer :
In a D.C. generator in case the resistance of the field winding is increased, then output voltage will decrease.
asked
Mar 21, 2018
by
anonymous
Answer :
In a D.C. generator, the critical resistance refers to the resistance of field.
asked
Mar 21, 2018
by
anonymous
Answer :
In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when there is no load on|he generator.
asked
Mar 21, 2018
by
anonymous
Answer :
The e.m.f. generated in a D.C. generator is directly proportional to speed of armature.
asked
Mar 21, 2018
by
anonymous
Answer :
In a D.C. generator the number of mechanical degrees and electrical degrees will be the same when number of poles is 2.
asked
Mar 20, 2018
by
anonymous
asked
Mar 20, 2018
by
anonymous
Answer :
In a D.C. generator the ripples in the direct e.m.f. generated are reduced by using carbon brushes of superior quality.
asked
Mar 20, 2018
by
anonymous
Answer :
Magnetic field in a D.C. generator is produced by electromagnets.
asked
Mar 20, 2018
by
anonymous
Answer :
The demagnetising component of armature reaction in a D.C. generator reduces generator e.m.f.
asked
Mar 20, 2018
by
anonymous
Answer :
If brushes of a D.C. generator are moved in order to bring these brushes in magnetic neutral axis, there will be crossmagnetisation as well as demagnetising.
asked
Mar 20, 2018
by
anonymous
Answer :
In case of a 4-pole D.C. generator provided with a two layer lap winding with sixteen coils, the pole pitch will be 8.
asked
Mar 20, 2018
by
anonymous
Answer :
A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be about 2 V.
asked
Mar 21, 2018
by
anonymous
Answer :
A D.C. generator can be considered as rotating amplifier.
asked
Mar 21, 2018
by
anonymous
Answer :
If a D.C. generator fails to build up the probable cause could not be field resistance less than the critical resistance.
asked
Mar 21, 2018
by
anonymous
Answer :
The armature core of a D.C. generator is usually made of silicon steel.
asked
Mar 20, 2018
by
anonymous
Description : For a D.C. generator when the number of poles and the number of armature conductors is fixed, then which winding will give the higher e.m.f. ?
Answer :
Wave winding
asked
Mar 20, 2018
by
anonymous
Answer :
The condition for maximum efficiency for a D.C. generator is variable losses equal to constant losses.
asked
Mar 20, 2018
by
anonymous
Answer :
The critical resistance of the D.C. generator is the resistance of field.
asked
Mar 21, 2018
by
anonymous
Answer :
Flashing the field of D.C. generator means creating residual magnetism by a D.C. source.
asked
Mar 21, 2018
by
anonymous
Answer :
D.C. generator generally preferred for charging automobile batteries is long shunt compound generator.
asked
Mar 20, 2018
by
anonymous
asked
Mar 20, 2018
by
anonymous
Description : What is the percentage of stray losses in DC machine?
Answer :
Percentage of stray losses in DC machine is about 1 % .
asked
Mar 8, 2018
by
anonymous
Answer :
Iron loss, copper loss and mechanical losses these are the losses in DC machine.
asked
Sep 27, 2017
by
anonymous
Answer :
In D.C. generators on no-load, the air gap flux distribution in space is flat topped.
asked
Mar 21, 2018
by
anonymous
Answer :
In case of D.C. machines, mechanical losses are primary function of speed.
asked
Mar 20, 2018
by
anonymous
Description : The fall in speed of a dc generator due to increase in load can be corrected by (1) cooling the armature.. (2) increasing the excitation. (3) reducing the load voltage. (4) increasing the input to the prime mover
Answer :
It can be corrected by increasing the input to the prime mover.
asked
May 1, 2018
by
anonymous
Description : The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : (A) 256 W (B) 320 W (C) 500 W (D) 625 W
Answer :
The eddy current loss in a dc generator is 400 W at 40 Hz frequency of reversal and constant flux density. When frequency is increased to 50 Hz., eddy current loss is : 625 W
asked
Apr 30, 2018
by
anonymous
Description : In a DC generator the windings of interpoles are connected : (A) in series with main field winding, to create a pole,of same polarity as the main pole ahead in the direction of rotation. (B) in series with main field winding, to create a pole of opposite polarity as the main pole ahead in the direction of ... in the direction of rotation. (D) in series with the armature winding, to create a pole of opposite polarity as the main pole ahead in the direction of rotation.
Answer :
In a DC generator the windings of interpoles are connected : in series with the armature winding, to create a pole of same polarity as the main pole ahead in the direction of rotation.
asked
Apr 29, 2018
by
anonymous
Description : The iron alloy, ALNICO is mainly used to make ________ A) Temporary magnets B) Permanent magnets C) Transmission lines D) None of these
Answer :
The iron alloy, ALNICO is mainly used to make Permanent magnets
asked
Apr 29, 2018
by
anonymous
Description : State the function of commutator in DC generator and name the material used for commutator.
Answer :
Function of Commutator: Commutator converts AC induced in armature winding into DC for external load. Material: i) Commutator segments are made up of Copper. ii) Commutator segments are insulated from each other by Mica.
asked
Jul 27, 2019
by
anonymous
Description : A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is
Answer :
A 200 V DC machine supplies 20 A at 200 V as a generator. The armature resistance is 0.2 Ohm. If the machine is now operated as a motor at same terminal voltage and current but with the flux increased by 10%, the ratio of motor speed to generator speed is 0.87
asked
May 8, 2018
by
anonymous
Description : The terminal characteristics of a dc generator suitable for electric welders is (A) separately excited generator (B) shunt generator (C) series generator (D) differentially compounded generator
Answer :
The terminal characteristics of a dc generator suitable for electric welders is differentially compounded generator
asked
Apr 28, 2018
by
anonymous
Description : What is the difference between an AC and DC generator?
Answer :
The generator which generates DC voltage is called DC generator and generator which generates AC voltage is called AC generator (or) Alternator. In DC generator armature is rotated and field winding ... generator. A DC generator can generate low voltages but an AC generator can generate upto 11kv.
asked
Mar 15, 2018
by
anonymous
Description : What is the principle of DC generator?
asked
Mar 15, 2018
by
anonymous
Description : From which material field coils of DC generator are made of?
Answer :
Field coils of DC generator are usually made of copper.
asked
Mar 3, 2018
by
anonymous
Description : Why is the armature of DC generator laminated?
Answer :
The armature of DC generator is laminated to reduce eddy current losses.
asked
Mar 3, 2018
by
anonymous
Answer :
Armature reaction in a generator results in demagnetisation of leading pole tip and magnetisation of trailing pole tip.
asked
Mar 21, 2018
by
anonymous
Answer :
In a separately excited generator supplying rated load the armature reaction is always present.
asked
Mar 21, 2018
by
anonymous
Answer :
In case of a flat compounded generator voltage remains constant irrespective of the load.
asked
Mar 21, 2018
by
anonymous
Description : The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be?
Answer :
The e.m.f. induced in the armature of a shunt generator is 600 V. The armature resistance is 0.1 ohm. If the armature current is 200 A, the terminal voltage will be 580 V.
asked
Mar 21, 2018
by
anonymous
asked
Mar 21, 2018
by
anonymous
Answer :
The purpose of providing dummy coils in a generator is to provide mechanical balance for the rotor.
asked
Mar 21, 2018
by
anonymous
Answer :
In over compounded generator, full load terminal voltage is more than no load terminal voltage.
asked
Mar 21, 2018
by
anonymous
Answer :
A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will be of 5 Hz.
asked
Mar 21, 2018
by
anonymous
Answer :
An exciter for a turbo generator is a shunt generator.
asked
Mar 21, 2018
by
anonymous