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

On state voltage drop - thyristor , On state  voltage  drop  It is...

On state  voltage  drop  It is  the maximum   instantaneous on state voltage  measured  under  pulse conditions to avoid  excessive dissipation at a particular junction  tem

Define resistance in lumped-circuit, Q. Define Resistance in lumped-circuit...

Q. Define Resistance in lumped-circuit? An ideal resistor is a circuit element with the property that the current through it is linearly proportional to the potential differenc

Explain the and gates - microprocessor, Explain the AND GATES - Microproces...

Explain the AND GATES - Microprocessor? The AND GATE has a logic 1 or high output if the entire inputs are high. The boolean and symbol expression for a 3-input AND gate is sho

Explain output ce characteristics, Q. Explain output CE characteristics? ...

Q. Explain output CE characteristics? 1. In the active region ic increases slowly as Vce increases. The slope of the curved is greater than the CB output characteristics. In co

Use a 4-to-1 multiplexer to simulate nand logic function, Q. Use a 4-to-1mu...

Q. Use a 4-to-1multiplexer to simulate the following: (a) NAND logic function. (b) EXCLUSIVE-OR logic function. (c) Σ m (1, 2, 4).

Develop and execute a p spice program, Q. In the circuit shown in Figure th...

Q. In the circuit shown in Figure the switch opens at t = 0. Develop and execute a P Spice program to solve for v(t), and use PROBE to obtain a plot of v(t). Hint: Use the follo

FET operation, ON output plot of a JFET n-channel transistor if ID is close...

ON output plot of a JFET n-channel transistor if ID is close to IDSS does the value of VGS close to VP?

Role of stakeholders in distribution reform, Role of StakeHolders in Distri...

Role of StakeHolders in Distribution Reform These challenges could be met only by comprehensive reforms in the distribution sector. Earlier, you have studied about the roles o

Calculate the mechanical speed of rotar, Calculate the mechanical speed of ...

Calculate the mechanical speed of rotar: An asynchronous machine of 460V, 25hp, 4 poles with rotor wound in Y has the following data (of the side stator): Resistance of the

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