Which of the following machines has heavy fluctuation of load ?
A. Printing machine
B. Punching machine
C. Planer
D. Lathe
Industrial Drives
In which of the following applications the load on motor changes in cyclic order ?
In which of the following applications the load on motor changes in cyclic order ?
A. Electric shovels
B. Cranes
C. Rolling mills
D. All of the above
For derries and winches which of the following drives can be used ?
For derries and winches which of the following drives can be used ?
A. Pole changing squirrel cage motors
B. D.C. motors with Ward-leonard con-trol
C. A.C. slip ring motors with variable resistance
D. Any of the above
In case of _______________ speed control by injecting e.m.f. in the rotor circuit is possible?
In case of _______________ speed control by injecting e.m.f. in the rotor circuit is possible?
A. d.c. shunt motor
B. schrage motor
C. synchronous motor
D. slip ring induction motor
___________________has least range of speed control?
___________________has least range of speed control?
A. Slip ring induction motor
B. Synchronous motor
C. D.C. shunt motor
D. Schrage motor
Flame proof motors are used in_________________?
Flame proof motors are used in_________________?
A. paper mills
B. steel mills
C. moist atmospheres
D. explosive atmospheres
In squirrel cage induction motors which of the following methods of starting cannot be used ?
In squirrel cage induction motors which of the following methods of starting cannot be used ?
A. Resistance in rotor circuit
B. Resistance in stator circuit
C. Auto-transformer starting
D. Star-delta starting
Heat control switches are used in__________________?
Heat control switches are used in__________________?
A. transformers
B. cooling ranges
C. three phase induction motors
D. single phase
In jaw crushers a motor has to often start against ____________________ load?
In jaw crushers a motor has to often start against ____________________ load?
A. heavy
B. medium
C. normal
D. low
Which of the following motors is usually preferred for kiln drives ?
Which of the following motors is usually preferred for kiln drives ?
A. Cascade controlled A.C. motor
B. Slip ring induction motor
C. Three phase shunt wound com-mutator motor
D. Any of the above