UP polytechnic Lecturer (EE) Quiz 18

Find the percentage loading at which maximum efficiency occur in a single phase transformer with full load iron and copper losses as 3 kW and 8 kW respectively.

Which of the following combinations of three phase transformer is rarely used due to harmonic considerations?

In an induction motor, number of stator slots should never be equal to number of rotor slots in order to prevent:

If a synchronous motor is running at a leading power factor, its excitation induced voltage (E_f) is:

What is the ratio of starting torque and maximum torque of a 3-phase, 50Hz, 4-pole induction motor when the maximum torque occurs at 1200 rpm?

A slip test is conducted on a synchronous generator to determine:

A 3 phase 10 –pole star connected alternator runs at 600 rpm. It has 140 slots with 10 conductor per slot. The slot harmonics may be of order?

A 10-pole lap wound DC armature has a total of 200 conductors, each with a current carrying capacity of 10 A. The average induced emf per conductor is 10 V. The power rating of the DC machine is

For a DC shunt generator at 800 rpm critical field resistance of 200 Ω. Now speed increased by 200 rpm. Change in critical field resistance is