Question is ⇒ Which of the following losses are significantly reduced by laminating the core of a D.C. generator ?, Options are ⇒ (A) Hysteresis losses, (B) Eddy current losses, (C) Copper losses, (D) Windage losses, (E) , Leave your comments or Download question paper.

Question is ⇒ Which of the following losses are significantly reduced by laminating the core of a D.C. generator ?, Options are ⇒ (A) Hysteresis losses, (B) Eddy current losses, (C) Copper losses, (D) Windage losses, (E) , Leave your comments or Download question paper. Previous question Next question


Q1.	Which of the following losses are significantly reduced by laminating the core of a D.C. generator ?
A.	Hysteresis losses [Wrong Answer]
B.	Eddy current losses [Correct Answer]
C.	Copper losses [Wrong Answer]
D.	Windage losses [Wrong Answer]
View Answer 3 -1 Explanation:- Answer : B Discuss it below : !! OOPS Login [Click here] is required to post your answer/result Help other students, write article, leave your comments

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⇒ Which of the following loss in a D.C. generator is dissipated in the form of heat ?
Mechanical loss
Core loss
Copper loss
All of the above

⇒ In case the conditions for maximum power for a D.C. motor are established, the efficiency of the motor will be
1
around 90%
anywhere between 75% and 90%
less than 50%

⇒ Speed control by Ward Leonard method gives uniform speed variation
in one direction
in both directions
below normal speed only
above normal speed only

⇒ The armature torque of the D.C. shunt motor is proportional to
field flux only
armature current only
both (a) and (b)
none of the above

⇒ The current drawn by the armature of D.C. motor is directly proportional to
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the speed of the motor
the voltage across the terminals
none of the above

⇒ A brake test on D.C. motors is usually restricted to
small horse power motors
variable speed motors
high speed motors
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⇒ Starters are used with D.C. motors because
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proportional to the square of the current
inversely proportional to the armature current

⇒ Which of the following methods is most effective in finding out the no load losses in a large D.C. shunt motor ?
Field's test
Ward-Leonard test
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⇒ Which of the following motors, on removal of load, will run at the highest speed ?
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part load
full-load
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⇒ If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens
this will make armature to take heavy current, possibly burning it
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⇒ 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

⇒ The retardation test is applicable to shunt motors and generators and is used to find
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the stray losses
the friction losses
the eddy current losses

⇒ In a D.C. generator, the iron losses mainly take place in
yoke
commutator
armature conductors
armature rotor

⇒ Which of the following method of speed control, of D.C. machine will offer minimum efficiency ?
Voltage control method
Field control method
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⇒ The plugging gives the
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smallest torque braking
highest torque braking
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⇒ In which of the following applications D.C. series motor is invariably tried?
Starter for a car
Drive for a water pump
Fan motor
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⇒ In Ward-Leonard control the lower limit of speed is imposed by
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core losses of motor
mechanical losses of motor and generator together
all of the above

⇒ A shearing machine has cyclic load consisting of intermittent light and henry loads. Which of the following D.C. motor will be suitable for this purpose?
Series motor
Shunt motor
Cumulative compound motor
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Cumulatively compounded motor
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eddy current losses
field copper losses
windage losses

⇒ The maximum end-play of a motor is about
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6 mm
2 mm
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(speed)^-1
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215 V
220 V
224 V

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air compressors
electric traction
machine shops

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Plugging
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