Electromechanical meters, Electrical Engineering

Assignment Help:

Electromechanical Meters

Electromechanical energy meters are based on the Ferraris Principle (see note in the margin). The working of these meters is explained.

Working of Electromechanical Meters

The meters have a revolving metallic disc mounted on jewel bearings or magnetic suspension bearings. The display is cyclometer or mechanical counters and accuracy is classically 1% or 2% (class 1.0 or 2.0). They  cater  to  limited  tariffs  applicable  majorly  to  1-phase  or  3- phase direct connected segment (whole current meters).The electromechanical induction meter operates through counting the revolutions of the disc that rotates at a speed proportional to the power consumed. 

The number of revolutions is, therefore, proportional to the energy usage.  The metallic  disc is acted upon through three magnetic fields,  one  proportional  to the voltage,  the other  to the current  and  a third  constant  field  supplied  by  a  permanent   magnet.  One  of  the varying  fields  induces  currents  in  the  metallic  disc,  that  are  then acted upon through the other varying field to produce a torque.

This  results  in  the  torque  being  proportional  to  the  product  of  the current  and voltage,  that is power.  As the metallic disc rotates through the permanent magnetic field, eddy currents are again produced that dissipate energy (because the disc has some resistance) and act to slow the rotation. This drag is proportional to the rotation speed. The equilibrium among the applied torque and the drag results within a speed proportional to the power. The rotating disc in this category of meter is, actually,  an  electric  motor  of  a category  known as  a reluctance  motor  or  eddy current motor. It consumes a little amount of power, classically around 2 W.


Related Discussions:- Electromechanical meters

Define the universal property of nand and nor gates, Define The universal p...

Define The universal property of NAND and NOR Gates? The NAND and NOR gates are called universal gates, because any gate can build by using these two gates. The univers

Find the current flow through a resistor, Q. Find the current flow through ...

Q. Find the current flow through a resistor ? Consider the circuit shown in Figure (a). Reduce the portion of the circuit to the left of terminals a-b to (a) a Thévenin equival

Clc filter, CLC or π Filter The above diagram displays CLC or π ty...

CLC or π Filter The above diagram displays CLC or π type filter, which mainly contains a capacitor filter, followed through LC section. This filter offers a quite smooth o

Power and power distribution, design a single phase circuit from a supply p...

design a single phase circuit from a supply point to a load

Comperators, How to build a 6 bit comparator?

How to build a 6 bit comparator?

States the superposition theorem, The superposition theorem states: 'In...

The superposition theorem states: 'In any network made up of linear resistances and having more than single source of e.m.f, the resultant current flowing in any branch is the

For parity flag - conditional jumps , For parity Flag  JPE ( jump on ...

For parity Flag  JPE ( jump on Parity even ) and  JPO  ( Jump or Parity Odd) Instruction JPE  transfer  the execution of the  program  to the specified memory  address i

When both mt2 and gate are positive, When both  MT 2 and  Gate  are pos...

When both  MT 2 and  Gate  are positive In this  junction  P 1 N 1   and P 2 N 2   are forward  biased whereas junction N 1 P 2 is reverse biased. The gate current flows  thr

Net force on the wire due to the interaction of the b-field, Q. (a) Show by...

Q. (a) Show by applying Ampere's circuital law that themagnetic field associated with a long straight, current-carrying wire is given by B φ = µ 0 I/(2πr), where the subscript φ d

What is threaded system, What is Threaded system. Threaded system: At...

What is Threaded system. Threaded system: At times we require implementing an operating system which can process multiple threads. Many threads are handled through the kernel

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd