26-02-2013, 10:44 AM
Calibration of Energy Meter
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APPARATUS:
•Energy Meter 1
•Watt Meter 1
•Load
•Connecting wires
THEORY:
Calibration is the validation of specific measurement techniques and equipment. At the
simplest level, calibration is a comparison between measurements-one of known
magnitude or correctness made or set with one device and another measurement made in
as similar a way as possible with a second device.
The device with the known or assigned correctness is called the standard. The second
device is the unit under test (UUT), test instrument (TI), or any of several other names for
the device being calibrated.
All the instruments which are calibrated in industry are compared with the standards of
ISO 9001 and ISO 9002. ISO stands for “International Organization for Standardization”.
An electric meter or energy meter is a device that measures the amount of electrical
energy consumed by a residence, business, or an electrically-powered device. The most
common type of energy meter consists of an aluminum disk and a dial.
Two tests are performed for the calibration of energy meter.
•Speed test (for the calibration of aluminum disk)
•Dial test (for the calibration of dial)
PROCEDURE:
SPPED TEST:
This test is carried out to calibrate the disc of energy meter.
1. Connect the circuit according to the circuit diagram.
2. Switch on the power supply and note the number of revolutions of the disc for
some time say 25s.
3. Note the reading of wattmeter and calculate True Energy by using formula.
4. Note the reading of energy meter and calculate the Observed Energy.
5. Calculate %age error between true and observed energy. Error should be within
limits 3.5%.
DIAL TEST:
This test is performed for the calibration of dial of energy meter.
1. Connect the circuit according to the circuit diagram.
2. Note the initial reading of the dial and call it Initial Energy.
3. Switch on the power supply and note the dial reading after some time. Call it
Final Energy.
4. The difference between these readings will give the Observed Energy.
5. Note the wattmeter reading and calculate the True Energy.
6. Calculate %age error. Error should be within limits 3.5%.