The correct answer is: A. can be operated either on D.C. or A.C. supply at approximately the same speed and output.
A universal motor is a type of electric motor that can be operated on either direct current (DC) or alternating current (AC). It is a single-phase motor that uses a squirrel-cage rotor. The stator of a universal motor has two windings: a main winding and a field winding. The main winding is connected to the power source, and the field winding is connected to a capacitor. The capacitor creates a magnetic field that interacts with the magnetic field of the main winding to create torque.
Universal motors are used in a variety of applications, including vacuum cleaners, power tools, and food mixers. They are also used in some electric vehicles.
Option B is incorrect because universal motors are not specifically designed to be marketed internationally. They can be used in any country that has a power supply that is compatible with the motor’s voltage and frequency.
Option C is incorrect because universal motors do not run at dangerously high speeds on no-load. In fact, they typically run at a lower speed on no-load than when they are under load.
Option D is incorrect because option A is the correct answer.