Question is ⇒ Between Field's test and Hopkinson's test the main common thing is that both, Options are ⇒ (A) use negligible power, (B) are regenerative tests, (C) need two similar mechanicallycoupled motors, (D) need two electrically coupled series motors, (E) , Leave your comments or Download question paper.

Question is ⇒ Between Field's test and Hopkinson's test the main common thing is that both, Options are ⇒ (A) use negligible power, (B) are regenerative tests, (C) need two similar mechanicallycoupled motors, (D) need two electrically coupled series motors, (E) , Leave your comments or Download question paper. Previous question Next question


Q1.	Between Field's test and Hopkinson's test the main common thing is that both
A.	use negligible power [Wrong Answer]
B.	are regenerative tests [Wrong Answer]
C.	need two similar mechanicallycoupled motors [Correct Answer]
D.	need two electrically coupled series motors [Wrong Answer]
View Answer 12 -3 Explanation:- Answer : C Discuss it below : !! OOPS Login [Click here] is required to post your answer/result Help other students, write article, leave your comments

Previous question Next question

Also Read Similar Questions Below :

⇒ Which D.C. motor will be suitable alongwith flywheel for intermittent light and heavy loads?
Series motor
Shunt motor
Cumulatively compounded motor
Differentially compounded motor

⇒ Torque developed by a D.C. motor depends upon
active length of the conductor
current flow through the conductors
number of conductors
radius of armature

⇒ Which D.C. motor is preferred for elevators ?
Shunt motor
Series motor
Differential compoun.d motor
Cumulative compound motor

⇒ In D.C. motor which of the following can sustain the maximum temperature rise?
Slip rings
Commutator
Field winding
Armature winding

⇒ Four point starter in the D.C. motor is used
to decrease the field current
to increase the field current
not to effect the current passing through Hold on coil even if any change M the field current takes place
all of the above

⇒ Which of the following methods is most ecoriomical fol. finding the no-load losses of a large b.C. shunt motor ?
Retardation test
Swinburne's test
Hopkinson's test
none of the above

⇒ If the terminals of armature of D.C. motor are interchanged, this action will offer following kind of braking
regenerative
plugging
dynamic braking
none of the above

⇒ In Field's test for series motors one motor drives the other machine as
cumulative compound generator
differential compound generator
separately excited generator
series generator

⇒ Speed control of a cumulatively compounded D.C. motor can be effected through change of
field resistance
armature resistance
armature voltage
any of the above

⇒ Buses, trains, trolleys, hoists, cranes require high starting torque and therefore make use of
D.C. series motor
D.C. shunt motor
induction motor
all of above motors

⇒ To get the speed of D.C. motor below the normal without wastage of electrical energy ____ is used.
Ward Leonard control
rheostatic control
any of the above method
none of the above method

⇒ Sparking at the commutator of a D.C. motor may result in
damage to commutator segments
damage to commutator insulation
increased power consumption
all of the above

⇒ Ward-Leonard control is basically a
voltage control method
field divertor method
field control method
armature resistance control method

⇒ Differentially compound D.C. motors can find applications requiring
high starting torque
low starting torque
variable speed
frequent on-off cycles

⇒ Usually wide and sensitive speed control is desired in case of
centrifugal pumps
elevators
steel rolling mills
colliery winders

⇒ In which of the following applications D.C. series motor is invariably tried?
Starter for a car
Drive for a water pump
Fan motor
Motor operation in A.C. or D.C.

⇒ If T_a be the torque and Ia the armature current for a D.C. motor, then which of the following relation is valid before saturation ?
T_a ∝ I_a
T_a ∝ I/I_a
T_a ∝ I_a²
T_a ∝ ^I/_{I_a²}

⇒ The armature shaft of a D.C. motor must be able to withstand
any unbalanced magnetic pull on the armature core
twisting strains due to transmission of torque
bending moment due to the weight of the armature and commutator
all of the above

⇒ When two D.C. series motors are connected in parallel, the resultant speed is
more than the normal speed
loss than the normal speed
normal speed
zero

⇒ The main disadvantage of the Ward- Leonard control method is
high initial cost
high maintenance cost
low efficiency at light loads
all of the above

⇒ The losses occurring in a D.C. generator are given below. Which loss is likely to have highest proportion at rated load of the generator ?
hysteresis loss
field copper loss
armature copper loss
eddy current loss

⇒ In hazardous area of gassy mines, material transportation is done by vehicles powered by
A.C. mains
D.C. mains
I.C. engines
batteries

⇒ The speed of a D.C. shunt motor more than its full-load speed can be obtained by
decreasing the field current
increasing the field current
decreasing the armature current
increasing the armature current

⇒ The power mentioned on the name plate of an electric motor indicates
the power drawn in kW
the power drawn in kVA
the gross power
the output power available at the shaft

⇒ In the D.C. motor the iron losses occur in
the field
the armature
the brushes
the commutator

⇒ All motors, basically, operate on the principie of either repulsion or
induction
semi-conduction
capacitance
electro-magnetism

⇒ If the supply voltage for a D.C. motor is increased, which of the following will decrease ?
Starting torque
Operating speed
Full-load current
All of the above

⇒ In regenerative braking
motor energy is dissipai.ed as heat
motor energy is dissipated in armature heating
motor energy is dissipated in windage losses
motor is rnade to run as a generator

⇒ Which of the following motors is most suitable for signalling devices and many kinds of timers ?
D.C. shunt motor
D.C. series motor
Induction motor
Reluctance motor

⇒ Which of the following statements is correct, in case of a D.C. series motor ?
It should be directly connected to the load
It may run away if its field becomes open
It is a constant speed motor
It cannot be used where high starting torque is required