Low frequency supply is obtained by
type of load is offered by cranes and hoists?
electric drive posses the following drawback :
the items in List I with those of List II and select your answers using the
codes given in the lists :
I List II
(Type of duty)
(A) Continuous duty 1. Machine tools
(B) Short time duty 2. Sirens
(C) Continuous duty 3. Blowers
(D) Continuous duty 4. Conveyors
starting and braking
pole-changing squirrel cage induction motor employed in derricks has four,
eight and twenty four pole. The lowest speed is used in :
Which motor has widest variety of methods for speed control?
suburban services as compared with urban service :
electric traction, the coefficient of adhesion is represented by
the speed-time curve of a train, speed in and time in are_________plotted.
locomotive exerts a tractive effort of 35,300 N in hauling a train at 48 km/h
on the level track. If the motor is to haul the same train on a gradient of 1
in 50 and the tractive effort required is 55,180N determine the power delivered
by the locomotive if it is driven by (i) dc series motors (ii) induction motors,
the transmission of power, a direct drive is only preferred when :
of the following is NOT an AC drive?
motor used in electric traction is
of the following methods is NOT used for DC drive?
approximate continuous rating of a motor for a load of 100 HP for 20 minutes at
3/4th load for next 10 minutes and a no
load for next 20 minutes is :
Which traction system employs the metadyn control method?
is the frequency of a single phase traction system?
Which of the below is an example of short time, intermittent loads?
load characteristics of rolling mill :
among the following is mechanical braking?
Which of the following motors one will choose to drive the rotary
energy consumption is maximum in_________ service.
In India diesel locomotives are manufactured at
Operating voltage for d.c. traction is
most preferred motor used in water pumping is :
In AC locomotives, squirrel cage induction motors are used, the method of speed control is :
motor enclosure used in wood-working industry is
electric train taking of constant current of 600A moves on a section of line
between two substation 8 km apart maintained at 575V and 590V respectively. The
track resistance is 0.04 Ohm per km both go and return. The point of minimum
potential along the track is at a distance from 575V substation is
The most economical method of electric braking is :
motor has to be selected for following load cycle. Load uniformly rising from
zero to 100 hp in 10 minutes after which it is constant at 100 hp for the next
10 minutes, followed by no load period of 30 minutes. Suitable size of
continuous rated motor is :
of the following is the cause of passive load?
duty cranes are used in which of the following?
main drawback of electric drive is that
type of frame is preferred for motors in moist surroundings?
basic elements of an electric drive are
speed time curve for urban service has no
What kind of operation(s) is/are performed in winch and crane
electric motor may give noise due to
least expensive drive is
of the following three-phase AC systems is used in electric traction?
Which of the following is preferred for automatic drives?
is the advantage of electric braking?
An electric train employing a d.c. series motor is running at a fixed
speed. When a sudden drop in voltage of supply takes place, then this results
rotary converter generally
low frequency supply is given to the singlet phase AC system for track
distance railways operate on
most preferred motor used in traction is :
duty cranes are used in
The characteristics of drive for crane hoisting is
used for elevators is generally