In the driving system of energy meter

Question

Question

This question was previously asked in

BPSC AE Paper 4 (General Engineering Science) 10 Nov 2022 Official Paper

there is a permanent magnet which is excited by the current flow through the coil
the core of electromagnet is absent
the series electromagnet does not play any role
the coil of shunt electro - magnet is called pressure coil

Answer 1

Driving system of Energy meter:

In this system there are two silicon steel laminated electromagnet.
The upper magnet called shunt magnet it carries a voltage coil consisting many turns of thin wire which connected to supply voltage so it's behave like a potential coil. Voltage coil is connected to the supply voltage.
The coil of shunt electro - magnet is called pressure coil
The lower magnet called series magnet it carries the two current coils consisting of few turns of thick wire and behave like a current coil. Current coils are connected in series with the circuit and load current passes through it.

F1 Jai 21.11.20 Pallavi D7

Key Points

Component	Construction
Driving system	In this system there are two silicon steel laminated electromagnet Upper magnet → Shunt magnet → behave as potential coil Lower magnet → series magnet → behave as current coil
Moving system	In this system a thin aluminum disk placed in the gap between the two electromagnets and mounted on a vertical shaft which is free to rotate.
Registering system	It registers the number of rotation of the disk which is proportional to the energy consumed directly in kilowatt-hour
Braking system	This system has a permanent magnet called brake magnet. It is located near the disk so that eddy currents are induced and braking toque to the disk.