The document discusses energy meters, which are used to measure the energy consumed by electrical loads. An energy meter integrates power consumption over time using a rotating aluminum disc that is driven by electromagnets and braked by permanent magnets. The rotation of the disc is proportional to the energy used, and is registered by a counting mechanism to display the kilowatt-hours of energy consumed. Energy meters are important for measuring domestic and industrial power usage.

1. SNS COLLEGE OF ENGINEERING
Kurumbapalayam (Po), Coimbatore – 641 107
An Autonomous Institution
Accredited by NBA – AICTE and Accredited by NAAC – UGC with ‘A’ Grade
Approved by AICTE, New Delhi & Affiliated to Anna University, Chennai
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
COURSE NAME : 19EE01 BASIC ELECTRICAL AND ELECTRONICS ENGINEERING
I YEAR /I SEMESTER MECHANICAL ENGINEERING
Unit 1 – Electrical Circuits and Measurements
Energy Meter

2. ENERGY
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Physics says “ Energy is the ability of work done with respect to time”
In Electrical terms Energy is power consumed with respect to time
How do I measure energy ?
What instrument/machine should use?

3. CASE
• What is he doing?
• How do he calculating?
• Why should he measure?
• Share your experiences!
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4. ENERGY METER
• The meter which is used for measuring the energy utilizes by the electrical
load is known as the energy meter.
• The energy is the total power consumed and utilized by the load at
a particular interval of time.
• It is used in domestic and industrial AC circuit for measuring the power
consumption.
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5. CONSTRUCTION OF ENERGY METER
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6. ASSESSMENT 1
1.The household energy meter is
A. An indicating instrument
B. A recording instrument
C. An integrating instrument
D. None of the above
2. The meter constant of single phase energy meter is expressed in terms of
A. Revolutions/kWh
B. kW/kWh
C. Amps/kW
D. Volts/kWh
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7. MECHANISM IN ENERGYMETER
The energy meter has four mechanism
• Driving System
• Moving System
• Braking System
• Registering System
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8. DRIVING MECHANISM
• The electromagnet is the main component of the driving system.
• The upper one is called the shunt electromagnet, and the lower one is called
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 carry the current proportional to the shunt voltage and called as
pressure coil.
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9. MOVING SYSTEM
• The moving system is the aluminium 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 of the magnetic field.
• This eddy current is cut by the magnetic flux. The interaction of the flux and
the disc induces the deflecting torque.
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10. BRAKING SYSTEM
1. The permanent magnet is used for reducing the rotation of the aluminium
disc.
2. The aluminium disc induces the eddy current because of their rotation.
3. The eddy current cut the magnetic flux of the permanent magnet and
hence produces the braking torque.
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11. REGISTRATION (COUNTING MECHANISM)
1. The main function of the registration or counting mechanism is to record the
number of rotations of the aluminium disc.
2. The rotation is directly proportional to the energy consumed by the loads in
the kilowatt hour.
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12. Assessment 2
1.If voltage supply to the energy meter is more than the rated value, energy
meter will run
A.Slow
B.Fast
C.Either of the above
D.None of the above
2.Aluminium is selected as the material for rotating disc of energy meter
because
A.It is good conductor
B.It is light
C.It is indigenously available
D.All of the above reasons
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13. REFERENCES
1. Bhattacharya. S.K, “Basic Electrical and Electronics Engineering”, Pearson
Education , (2017)
2. Muthu Subramanian R, Salivahanan S,“ Basic Electrical and Electronics
Engineering”, Tata McGraw Hill Publishers, (2009)
3. V.Mittle“ Basic Electrical Engineering”, Tata McGraw Hill Publishers,
(2017)
4. Nagrath. I.J, “Electronics: Analog and Digital”, Prentice Hall India Pvt.
Ltd., (2013)
THANK YOU
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