The terminal voltage of a DC shunt generator drops on load because of all of the following except :

(A) Armature reaction

(B) Armature resistance drop

(C) Commutation

(D) Field weakening due to armature reaction and armature resistance drop

2 Answers

Answer :

The terminal voltage of a DC shunt generator drops on load because of all of the following except : Commutation

Answer :

(D) Field weakening due to armature reaction and armature resistance drop

Related questions

Description : The simplest method of controlling the terminal voltage of compound-wound DC generator is with a _____________. A. hand-operated field rheostat connected in series with the shunt field circuit B. ... in series with the load D. balance coil diverting neutral current through the shunt field

Last Answer : Answer: A

Description : A dc shunt generator has a speed of 800 rpm when delivering 20 A to the load at the terminal voltage of 220V. If the same machine is run as a motor it takes a line current of 20A from 220V supply. The speed of ... . (B) more than 800 rpm. (C) less than 800 rpm. (D) both higher or lower than 800 rpm.

Last Answer : (C) less than 800 rpm.

Description : In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will   (a) Improve but terminal voltage will fall   (b) ... will fall   (c) Improve and terminal voltage will rise   (d) worsen and terminal voltage will rise 

Last Answer : In a DC shunt generator working on load, the brushes are moved forward in the direction of rotation, as a result of this, commutation will Improve but terminal voltage will fall 

Last Answer : In a level compounded D.C. generator, full load terminal voltage is equal to no-load terminal voltage.

Last Answer : In over compounded generator, full load terminal voltage is more than no load terminal voltage.

Description : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave?

Last 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.

Description : Which of the terms listed best describes a compound-wound DC generator having a higher voltage at no load than at full load? A. Flat compounded B. Over compounded C. Under compounded D. Terminal compounded

Last Answer : Answer: C

Description : What are the reason of fall of terminal voltage of a D.C.Shunt generator?

Last Answer : As the load current increases, the terminal voltage tends todrop due to increased current and drop in voltage due to internalwinding resistance.

Description : A d.c. shunt motor runs at no load speed of 1140 r.p.m. At full load, armature reaction weakens the main flux by 5% whereas the armature circuit voltage drops by 10%. The motor full load speed in r.p.m. is (A) 1080 (B) 1203 (C) 1000 (D) 1200

Last Answer : (A) 1080

Last Answer : A cumulatively compounded long shunt generator when operating as a motor would be differentially compounded long shunt.

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?

Last 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.

Description : A shunt generator running at 1000 r.p.m. has generated e.m.f. as 200 V. If the speed increases to 1200 r.p.m., the generated e.m.f. will be nearly?

Last Answer : 200V/E2 = 1000/1200 E2= 240 V

Description : To conduct load test on a dc shunt motor, it is coupled to a generator which is identical to the motor. The field of the generator is also connected to the same supply source as the motor. The armature of generator is ... value of this load resistance is  (A) 1.0 (B) 0.98 (C) 0.96 (D) 0.94

Last Answer : To conduct load test on a dc shunt motor, it is coupled to a generator which is identical to the motor. The field of the generator is also connected to the same supply source as the motor. ... obtain rated armature current in both motor and generator. The p.u value of this load resistance is 0.96

Description :  An 8 pole lap wound DC shunt generator is supplying 295A to a load. The field current of the generator is 5A. The current per parallel path is: -  a) 300A b) 200A c) 150A d) 37.5A

Last Answer :  An 8 pole lap wound DC shunt generator is supplying 295A to a load. The field current of the generator is 5A. The current per parallel path is: - 37.5A

Description : One method of testing for a reversed shunt field coil in a DC generator or motor is by connecting the field to a direct current source, at reduced field rated voltage, and test for ... placed near each field C. test lamp across adjacent fields D. copper jumper across the interpole connections

Last Answer : Answer: B

Description : Shunt generator gives full voltage on load and the voltage drop as the load on the generator a. Decreases b. Increases c. Remains the same d. None of above 

Last Answer : Shunt generator gives full voltage on load and the voltage drop as the load on the generator a. Decreases b. Increases c. Remains the same d. None of above 

Description : A 8-pole, DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is  (A) 96 V (B) 192 V (C) 384 V (D) 768 V

Last Answer : A 8-pole, DC generator has a simplex wave-wound armature containing 32 coils of 6 turns each. Its flux per pole is 0.06 Wb. The machine is running at 250 rpm. The induced armature voltage is 384 V

Description : The slight curvature at the lower end of the O.C.C. of a self-excited dc generator is due to  1. residual pole flux 2. high armature speed 3.magnetic inertia 4. high field circuit resistance

Last Answer : The slight curvature at the lower end of the O.C.C. of a self-excited dc generator is due to magnetic inertia

Description : A compound generator has a no-load voltage of 250 volts and a full-load voltage of 230 volts, and therefore, is considered to be _____________. A. flat compounded B. over compounded C. under compounded D. terminal compounded

Last Answer : Answer: C

Last Answer : In a separately excited generator supplying rated load the armature reaction is always present.

Description : The voltage built-up process of a d.c. generator is  1. difficult 2. delayed 3. cumulative 4. Infinite 

Last Answer : The voltage built-up process of a d.c. generator is cumulative 

Description : for the voltage built-up a self-excited D.C. generator, which of the following is not an essential condition.  1.there must be some residual flux  2.field winding mmf must aid the residual ... 3.total field circuit resistance must be less than t critical value  4.armature speed must be very high

Last Answer : for the voltage built-up a self-excited D.C. generator, which of the following is not an essential condition.  1.there must be some residual flux  2.field winding mmf must aid the ... .total field circuit resistance must be less than t critical value  4.armature speed must be very high

Last Answer : A 220 V D.C. generator is run at full speed without any excitation. The open circuit voltage will be about 2 V.

Last Answer : In a D.C. generator in case the resistance of the field winding is increased, then output voltage will decrease.

Description : Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer

Last Answer : Answer: D

Description : A shunt-wound DC generator is one in which the shunt field windings are in parallel with the _____________. A. commutator B. brushes C. armature D. all of the above

Last Answer : Answer: D

Description : A DC shunt generator has its field windings connected in _____________. A. series with the series windings B. parallel with the field rheostat C. series with the armature windings D. parallel with the armature windings

Last Answer : Answer: D

Description : A variable shunt, connected across the series field coils of a DC compound wound generator, to permit adjustment of the degree of compounding, is called a _____________. A. divider B. diverter C. converter D. rheostat

Last Answer : Answer: B

Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead

Last Answer : Answer: A

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

Last Answer : The terminal characteristics of a dc generator suitable for electric welders is differentially compounded generator

Description : Rain drops falling through atmospheric air attain limited terminal velocity, because of (A) Upward thrust due to air (B) Viscous force exerted by air (C) Surface tension effects of water (D) Force of gravity

Last Answer : Option B

Last Answer : The purpose of retardation test on D.C. shunt machines is to find out stray losses.

Description : Which of the methods listed is used to maintain the division of load between two compound-wound, DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt ... generators are connected in series. D. The equalizer connection parallels the series fields of all machines.

Last Answer : Answer: D

Description : An open armature connection in a DC propulsion motor could be caused by ____________. A. low-load operation B. clogged ventilation ducts C. sparking at the brushes D. a grounded shunt field coil

Last Answer : Answer: B

Description : The shunt of a DC ammeter should be connected in __________. A. series with the load and in parallel with the meter movement B. parallel with the load and in series with the meter movement C. ... and in parallel with the meter movement D. series with the load and in series with the meter movement

Last Answer : Answer: A

Description : Which of the methods listed is used to maintain equal load sharing between two compound wound DC generators operating in parallel? A. The shunt fields are interconnected. B. The shunt field rheostats ... are connected in series. D. The series fields of both generators are connected in parallel.

Last Answer : Answer: D

Description : Regenerative braking (A) Can be used for stopping a motor. (B) Cannot be easily applied to DC series motors. (C) Can be easily applied to DC shunt motors (D) Cannot be used when motor load has overhauling characteristics.

Last Answer : Ans: B Because reversal of Ia would also mean reversal of field and hence of Eb

Description : Why shouldn’t a DC shunt motor start on the heavy load setting?

Last Answer : A series motor never started at no load and a shunt motor is never started at on load.

Description : What will happen when a DC shunt motor is started with a load?

Last Answer : Starting current will be very high so motor will take more current from supply. It may damage the armature winding.

Description : Why does the speed of a DC shunt motor decrease as the load increases?

Last Answer : Because if the load is increasing then the torque must also be increase. If not then the speed of motor will decrease.

Description : A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be

Last Answer : A 240 V, dc shunt motor draws 15 A while supplying the rated load at a speed of 80 rad/s. The armature resistance is 0.5 W and the field winding resistance is 80 W. The net Voltage across armature resistance at the time of plugging will be 474 V

Description : A shunt generator develops stable output voltage if (A) magnetization characteristic is linear (B) magnetization characteristic is non-linear (C) the field winding resistance is more than the critical resistance (D) the residual magnetism is equal to zero

Last Answer : A shunt generator develops stable output voltage if magnetization characteristic is non-linear

Description : A short in the shunt field of a DC motor is best located by _____________. A. visual inspection of the commutator B. applying AC voltage to each field coil and measuring the voltage drop across ... using a growler and hacksaw blade D. isolating each coil from the others and using a megohmmeter

Last Answer : Answer: B

Description : When 220V dc shunt alternator generating the voltage at rated value. If direction of rotation is reversed, then alternator will a) Build up its voltage with same polarity b) Build up its voltage with opposite polarity c) No build up of voltage d) None

Last Answer : Ans: No build up of voltage

Description : An unsaturated dc shunt motor runs at its rated speed when rated voltage is applied to it. If the supply voltage to the motor is reduced by 25%, the speed of the motor  (a) Increases by 25% (b) Remains the same (c) Decreases by 25% (d) Decrease only slightly by an amount less than 25% 

Last Answer : An unsaturated dc shunt motor runs at its rated speed when rated voltage is applied to it. If the supply voltage to the motor is reduced by 25%, the speed of the motor Remains the same

Description : When paralleling two alternators using three synchronizing lamps, the flickering of all three lamps becomes progressively slower and slower. This means the ______________. A. frequency of the incoming ... the bus D. terminal voltage of the incoming alternator is approaching that of the bus

Last Answer : Answer: A

Description : What are the factors, which varies terminal voltage of generator?

Last Answer : a) Voltage drop due to resistance (Ra drop). This is negligible. b) Voltage drops due to leakage reactance (XL). c) Voltage drops due to armature reaction. 

Description : Cathode rays in a discharge tube are made up of electrons emitted from the plate that is connected to the negative terminal of the DC voltage source.

Last Answer : Cathode rays in a discharge tube are made up of electrons emitted from the plate that is connected to the negative terminal of the DC voltage source.

Description : In the illustration, the component VR2 on the A1 AMPLIFIER MODULE is _________. EL-0060 A. a zener diode to regulate the +9 volt power supply from common B. a variable resistor diode to control the output to terminal ... 2 at 9.1 volts DC D. a tunnel diode with a breakdown voltage of 6.6 Volts DC

Last Answer : Answer: C