Single phase induction type energy meter is also popularly known as watt-hour meter. This name is given to it. This article is only focused about its constructional features and its working. Induction type energy meter essentially consists of following components:
1. Driving system
2. Moving system
3. Braking system and
4. Registering system
It consists of two electromagnets, called “shunt” magnet and “series” magnet, of laminated construction. A coil having large number of turns of fine wire is wound on the middle limb of the shunt magnet.
This coil is known as “pressure or voltage” coil and is connected across the supply mains. This voltage coil has many turns and is arranged to be as highly inductive as possible. In other words, the voltage coil produces a high ratio of inductance to resistance.
This causes the current and therefore the flux, to lag the supply voltage by nearly 90 degree. Single-phase induction kilowatt hour meter - Construction
Single-phase induction kilowatt hour meter - Construction
An adjustable copper shading rings are provided on the central limb of the shunt magnet to make the phase angle displacement between magnetic field set up by shunt magnet and supply voltage is approximately 90 degree.
The copper shading bands are also called the power factor compensator or compensating loop. The series electromagnet is energized by a coil, known as “current” coil which is connected in series with the load so that it carry the load current. The flux produced by this magnet is proportional to, and in phase with the load current.
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The moving system essentially consists of a light rotating aluminium disk mounted on a vertical spindle or shaft. The shaft that supports the aluminium disk is connected by a gear arrangement to the clock mechanism on the front of the meter to provide information that consumed energy by the load.
The time varying (sinusoidal) fluxes produced by...
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