Question
Download Solution PDFThe speed of the aluminum disc in an energy meter is controlled by __________.
Answer (Detailed Solution Below)
Detailed Solution
Download Solution PDFEnergy meter
The meter which is used for measuring the energy utilized by the electric load is known as the energy meter.
It is a type of integrating instrument.
Construction of Energy Meter
1.) Driving System
- The electromagnet is the main component of the driving system.
- The driving system has two electromagnets. The upper one is called the shunt electromagnet, and the lower one is called the series electromagnet.
- The series electromagnet is excited by the load current flow through the current coil.
- The coil of the shunt electromagnet is directly connected with the supply and hence carries the current proportional to the shunt voltage. This coil is called the pressure coil.
- The center limb of the magnet has a copper band. These bands are adjustable. The main function of the copper band is to align the flux produced by the shunt magnet in such a way that it is exactly perpendicular to the supplied voltage.
2.) Moving System
- The moving system is the aluminum disc mounted on the shaft of the alloy.
- The disc is placed in the air gap of the two electromagnets.
- The eddy current is induced in the disc because of the change in the magnetic field. This eddy current is cut by the magnetic flux. The interaction of the flux and the disc induces the deflecting torque.
- When the devices consume power, the aluminum disc starts rotating, and after some number of rotations, the disc displays the unit used by the load.
3.) Braking system
- The permanent magnet is used for reducing the rotation of the aluminum disc.
- The braking torque opposes the movement of the disc, thus reducing its speed.
- The permanent magnet is adjustable due to which the braking torque is also adjusted by shifting the magnet to the other radial position.
4.) Registration (Counting Mechanism)
- The main function of the registration or counting mechanism is to record the number of rotations of the aluminum disc.
- Their rotation is directly proportional to the energy consumed by the loads in the kilowatt hour.
Last updated on Jul 1, 2025
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