Related Questions

If a D.C. shunt motor is working at full load and if shunt field circuit suddenly opens
A This will make armature to take heavy current, possibly burning it
B This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
C Nothing will happen to motor
D Motor will come to stop
If a D.C. shunt motor is working at no load and if shunt field circuit suddenly opens
A Nothing will happen to the motor
B This will make armature to take heavy current, possibly burning it
C This will result in excessive speed, possibly destroying armature due to excessive centrifugal stresses
D Motor will run at very slow speed
In case of D.C. shunt motors the speed is dependent on back e.m.f. only because
A Back e.m.f. is equal to armature drop
B Armature drop is negligible
C Flux is proportional to armature current
D Flux is practically constant in D.C. shunt motors
D.C. shunt motors are used for driving
A Trains
B Cranes
C Hoists
D Machine tools
Which one of the following is not necessarily the advantage of D.C. motors over A.C. motors?
A Low cost
B Wide speed range
C Stability
D High starting torque
Under conditions of equal reduced pressure and equal reduced temperature, substances are said to be in the 'corresponding states'. At equal reduced conditions i.e., at the corresponding state, the __________ of different gases are nearly the same.
A Compressibility
B Molecular weight
C Humidity
D None of these
When the axis of load lies in the plane of rivet group, then the most heavily loaded rivet will be the one which (where, Fa is the load shared by each rivet due to axial load and Fm is the shearing load due to moment in any rivet.)
A Is at the maximum distance from CG of the rivet group
B Is at the minimum distance from CG of the rivet group
C Gives the maximum angle between the two forces Fa and Fm
D Gives the minimum angle between the two forces Fa and Fm
In testing a pile by load test, pile platform is loaded with one and half times the design load and a maximum settlement is noted. The load is gradually removed and the consequent rebound is measured. For a safe pile, the net settlement (i.e. total settlement minus rebound) per tonne of test load should not exceed
A 10 mm
B 15 mm
C 20 mm
D 25 mm
In _________ method of staging three phase induction motors the starting voltage is not reduced.
A Autotransformer
B Star-delta
C Slip ring
D Any of the above
The speed of a DC shunt motor is required to be more than full load speed . This is possible by-
A reducing the field current
B decreasing the armature current
C increasing the armature current
D None of the above

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