•• Q-1: Different between megger and contact resistance meter?
Answers: Megger used to measure cable resistance, conductor continuity, and phase identification where as contact resistance meter used to measure low resistance like relays, contactors.
•• Q-2: Why should be the frequency is 50 Hz only why not others like 45, 95 56 or anything, why should we maintain the frequency constant if so why it is only 50?
Answers: We can have the frequency at any frequency you like, but then you must also make your own motors, transformers or any other equipment you want to use. We maintain the frequency at 50 Hz or 60 Hz cos the world maintains a standard at 50 /60hz and the equipment are made to operate at these frequency.
•• Q-3: Why field rheostat is kept in minimum position while armature rheostat at maximum position?
Answers: In motors at the time of starting the armature resistance is introduced to reduce the high starting current and the field resistance is kept minimum to have high starting