TOPICS PAGE NO.
VERIFICATION OF KCL AND KVL. 01
THREE AMMETER METHOD. 03
THREE VOLT METER METHOD. 06
THREE PHASE POWER MEASUREMENT. 09
CALIBRATION OF WATTMETER BY VOLT METER
AND AMMETER. 12
CALIBRATION OF ENERGY METER BY DIRECT
LOADING 14
CALIBRATION OF WATTMETER BY PHANTOM
LOADING 16
MEASUREMENT OF INDUCTANCE 19
RLC SERIES CIRCUIT 22
CALIBRATION OF ENERGY METER BY PHANTOM
LOADING 24
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 1
VERIFICATION OF KCL&KVL
AIM
To verify KCL&KVL in dc circuit.
CIRCUIT DIAGRAM
APPARATUS REQUIRED
THEORY
𝑲𝑰𝑹𝑪𝑯𝑶𝑭𝑭’𝒔 𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒍𝒂𝒘(𝑲𝑪𝑳)
𝑰𝒕 𝒔𝒕𝒂𝒕𝒆𝒔 𝒕𝒉𝒂𝒕 𝒂𝒍𝒈𝒆𝒃𝒓𝒂𝒊𝒄 𝒔𝒖𝒎 𝒐𝒇 𝒕𝒉𝒆 𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒎𝒆𝒆𝒕𝒊𝒏𝒈 𝒂𝒕 𝒂𝒏𝒚 𝒋𝒖𝒏𝒄𝒕𝒊𝒐𝒏 𝒊𝒔 𝒛𝒆𝒓𝒐.
Ʃ𝑰 = 𝟎
Sl No Apparatus Specification Quantity
1
2
3
4
Autotransformer
Voltmeter
Ammeter
Rheostat
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 2
𝑲𝑰𝑹𝑪𝑯𝑶𝑭𝑭’𝒔 𝒗𝒐𝒍𝒕𝒂𝒈𝒆 𝒍𝒂𝒘(𝑲𝒗𝑳)
𝑰𝒕 𝒔𝒕𝒂𝒕𝒆𝒔 𝒕𝒉𝒂𝒕 𝒊𝒏 𝒂𝒄𝒍𝒐𝒔𝒆𝒅 𝒎𝒆𝒔𝒉,𝒂𝒍𝒈𝒆𝒃𝒓𝒂𝒊𝒄 𝒔𝒖𝒎 𝒐𝒇 𝒕𝒉𝒆 𝒗𝒐𝒍𝒕𝒂𝒈𝒆 𝒅𝒓𝒐𝒑 𝒊𝒏 𝒓𝒆𝒔𝒊𝒔𝒕𝒐𝒓𝒔 𝒂𝒏𝒅 𝒆𝒎𝒇’𝒔 𝒆𝒒𝒖𝒂𝒍 𝒕𝒐 𝒛𝒆𝒓𝒐
𝑰𝒆,Ʃ𝑰𝑹 + Ʃ𝑬𝑴𝑭𝒔 = 𝟎
PROCEDURE
1. Connect the circuit as in the connection diagram.
2. Check the connections and correct the mistake if any.
3. Switch on the supply
4. Vary the autotransformer dor different readings.
5. Take all meter readings& tabulate
6. Verify kcl & kvl.
TABULATION
Sl no V1 V2 V3 V2+V3 I1 I2 I3 I2+I3
RESULT
Verified Kirchhoff’s current law &voltage law
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 3
MEASUREMENT OF SINGLE PHASE POWER AND POWER FACTOR
USING THREE AMMETERS.
AIM
To measure the power and power factor of the given R-L circuit using three Ammeters.
(Without using Wattmeter)
CIRCUIT DIAGRAM
APPARATUS REQUIRED
Sl No Apparatus Specification Quantity
1
2
3
4
5
Ammeter
Voltmeter
Rheostat
Autotransformer
Transformer
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 4
THEORY
Power factor is the cosine of the angle between phase voltage and current. The maximum value of power
factor is unity, i.e. for pure resistive load and minimum value is zero.ie for pure inductive load (lagging) or pure
capacitive load (leading).
For an R-L circuit, the current lags voltage by certain angle, which is called the power factor angle ø.
The vector diagram is shown in figure. Voltage V is taken as the reference, I2is in phase with V (since
current through pure resistance- in phase with V,), I3 lags behind V by angle ø, (since R-L circuit), I1 is the
vector sum of I2 and I3.
𝐼12 = (𝐼2 + 𝐼3𝐶𝑜𝑠ø)2 + ( 𝐼3𝑆𝑖𝑛ø)2
= 𝐼22 + 𝐼3
2𝐶𝑜𝑠2ø + 2𝐼2𝐼3𝐶𝑜𝑠ø + 𝐼32𝑆𝑖𝑛2 ø
= 𝐼22 + 𝐼3
2 + 2𝐼2𝐼3 𝐶𝑜𝑠ø
𝑃𝐹 = ( 𝐼12 − 𝐼2
2 − 𝐼32)/2𝐼2𝐼3
𝑊𝑒 𝑎𝑣𝑒 𝑉 = 𝐼2𝑅
𝑆𝑜, 𝑃𝑜𝑤𝑒𝑟 𝐶𝑜𝑛𝑠𝑢𝑚𝑒𝑑 𝑏𝑦 𝑡𝑒 𝑙𝑜𝑎𝑑 = 𝑉𝐼3𝐶𝑜𝑠ø
= 𝐼2𝑅 𝐼3 ( 𝐼12 − 𝐼2
2 − 𝐼32)/2𝐼2𝐼3
𝑃𝑜𝑤𝑒𝑟 = 𝑅
2 ( 𝐼1
2 − 𝐼22 − 𝐼3
2)
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 5
PROCEDURE:
1. Connect the circuit as in the connection diagram.
2. Check the connections and correct the mistake if any.
3. Switch on the supply
4. Adjust the auto transformer upto rated voltage of the load.
5. Adjust the load for different readings.
6. Calculate the results accordingly.
TABULATION
Sl No V/m
Reading-
Volts
I1
Amps
I2
Amps
I3
Amps
Power=
R/2(I12-I2
2-I3
2)
PF=
(I12-I2
2-I3
2)/2 I2I3
RESULT
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 6
MEASUREMENT OF SINGLE PHASE POWER AND POWER FACTOR
USING THREE VOLTMETERS.
AIM
To measure the power and power factor of the given R-L circuit using three voltmeters.
(Without using Wattmeter)
CIRCUIT DIAGRAM
APPARATUS REQUIRED
THEORY
Power
factor is the
cosine of
the angle
between phase voltage and current. The maximum value of power factor is unity, i.e. for pure resistive load and
minimum value is zero.ie for pure inductive load (lagging) or pure capacitive load (leading).
For an R-L circuit, the current lags voltage by certain angle, which is called the power factor angle ø.
Sl No Apparatus Specification Quantity
1
2
3
4
5
Ammeter
Voltmeter
Rheostat
Autotransformer
Transformer
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 7
The vector diagram is shown in figure. Current I is taken as the reference, V2 in phase with I ( since current
through pure resistance- in phase with V,), V3 Leads current I by angle ø, (since R-L circuit), V1 is the vector
sum of V2 and V3.
V12= (V2+V3Cosø)
2+ ( V3Sinø)
2
= V22+V3
2Cos
2ø+2V2V3Cosø+V3
2Sin
2 ø
= V22+V3
2+2 V2V3 Cosø
... PF=( V1
2-V2
2-V3
2)/2 V2V3
We have V2= IR
So, Power Consumed by the load= V3ICosø
= ( V12-V2
2-V3
2)/2 R
Power =( V12-V2
2-V3
2)/2 R
`
PROCEDURE:
1. Connect the circuit as in the connection diagram.
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 8
2. Check the connections and correct the mistake if any.
3. Switch on the supply
4. Adjust the auto transformer upto rated voltage of the load.
5. Adjust the load for different readings.
6. Calculate the results accordingly.
p
TABULATION
Sl No V/m
Reading-
Volts
V1
Amps
V2
Amps
V3
Amps
Power=
(V12-V2
2-V3
2)/2R
PF=
(V12-V2
2-
V32)/2V2V3
RESULT
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 9
MEASUREMENT OF THREE PHASE POWER AND POWER FACTOR USING
TWO WATTMETERS
AIM
To measure the input power and determine power factor of a balanced three phase load using two W/ms.
CIRCUIT DIAGRAM
APPARATUS REQUIRED
Sl No Apparatus Specification Quantity
1
2
3
4
5
Three phase autotransformer
Voltmeter
Ammeter
Wattmeter
Rheostat
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 10
THEORY:
𝑻𝒉𝒆 𝒇𝒐𝒍𝒍𝒐𝒘𝒊𝒏𝒈 𝒎𝒆𝒕𝒉𝒐𝒅𝒔 𝒂𝒓𝒆 𝒖𝒔𝒆𝒅 𝒇𝒐𝒓 𝒕𝒉𝒆 𝒎𝒆𝒂𝒔𝒖𝒓𝒆𝒎𝒆𝒏𝒕 𝒐𝒇 𝒕 𝒉𝒆𝒓𝒆 𝒑𝒉𝒂𝒔𝒆 𝒑𝒐𝒘𝒆𝒓.
𝟏. 𝑶𝒏𝒆 𝒘𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 𝒎𝒆𝒕𝒉𝒐𝒅 − 𝑭𝒐𝒓 𝒃𝒂𝒍𝒂𝒏𝒄𝒆𝒅 𝒍𝒐𝒂𝒅.
𝟐. 𝑻𝒘𝒐 𝑾𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 𝒎𝒆𝒕𝒉𝒐𝒅 – 𝑭𝒐𝒓 𝑩𝒂𝒍𝒂𝒏𝒄𝒆𝒅 / 𝑼𝒏𝒃𝒂𝒍𝒂𝒏𝒄𝒆𝒅 𝒍𝒐𝒂𝒅.
𝟑. 𝑻𝒉𝒓𝒆𝒆 𝒘𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 𝒎𝒆𝒕𝒉𝒐𝒅 − 𝑭𝒐𝒓 𝑩𝒂𝒍𝒂𝒏𝒄𝒆𝒅 / 𝑼𝒏𝒃𝒂𝒍𝒂𝒏𝒄𝒆𝒅 𝒍𝒐𝒂𝒅.
Two W/m Method: - (Balanced load)
𝑳𝒆𝒕 𝒕𝒉𝒆 𝒍𝒐𝒂𝒅 𝒃𝒆 𝒂 𝟑 ø 𝒃𝒂𝒍𝒂𝒏𝒄𝒆𝒅 𝒔𝒕𝒂𝒓 𝒄𝒐𝒏𝒏𝒆𝒄𝒕𝒆𝒅 𝒐𝒏𝒆.
𝑳𝒐𝒂𝒅 𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒕𝒉𝒓𝒐𝒖𝒈𝒉 𝒘𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 𝑾𝟏 𝒊𝒔 𝑰 𝑹 𝒂𝒏𝒅. 𝒗𝒐𝒍𝒕𝒂𝒈𝒆 𝒂𝒄𝒓𝒐𝒔𝒔 𝒕𝒉𝒆 𝒗𝒐𝒍𝒕𝒂𝒈𝒆 𝒄𝒐𝒊𝒍 𝒐𝒇 𝒕𝒉𝒆 𝑾
/𝒎 𝑾𝟏 𝒊𝒔 𝑽𝑹𝒀 = 𝑽𝑹 − 𝑽𝒀
𝑹𝒆𝒂𝒅𝒊𝒏𝒈 𝒐𝒇 𝒘𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 𝟏 = 𝑽𝑹𝒀𝑰 𝑹𝑪𝒐𝒔 (𝟑𝟎 + ø) = 𝑽𝑳 𝑰 𝑳𝑪𝒐𝒔 (𝟑𝟎 + ø)
𝑵𝒐𝒘 𝒄𝒖𝒓𝒓𝒆𝒏𝒕 𝒕𝒉𝒓𝒐𝒖𝒈𝒉 𝒘𝒂𝒕𝒕𝒎𝒆𝒕𝒆𝒓 − 𝟐 = 𝑰𝑩
𝑷 𝑫 𝒂𝒄𝒓𝒐𝒔𝒔 𝑾𝟐 = 𝑽𝑩𝒀 = 𝑽𝑩 − 𝑽𝒀
𝑷𝒉𝒂𝒔𝒆 𝒅𝒊𝒇𝒇𝒆𝒓𝒆𝒏𝒄𝒆 𝒃𝒆𝒕𝒘𝒆𝒆𝒏 𝑰 𝑩𝒂𝒏𝒅 𝑽𝑩𝒀 𝒊𝒔 (𝟑𝟎 − ø)
𝑹𝒆𝒂𝒅𝒊𝒏𝒈 𝒐𝒇 𝑾𝟐 = 𝑽𝑩𝒀𝑰𝑩 𝑪𝒐𝒔(𝟑𝟎 − ø)
𝑺𝒊𝒏𝒄𝒆 𝒕𝒉𝒆 𝒍𝒐𝒂𝒅 𝒊𝒔 𝒃𝒂𝒍𝒂𝒏𝒄𝒆𝒅 𝑽𝑹𝒀 = 𝑽𝑩𝒀 = 𝑽𝑩𝑹 = 𝑽𝑳
𝑺𝒊𝒎𝒊𝒍𝒂𝒓𝒍𝒚 𝑰𝑹 = 𝑰𝒀 = 𝑰𝑩 = 𝑰𝑳
𝑇𝑒𝑛 𝑡𝑒 𝑠𝑢𝑚 𝑜𝑓 𝑤𝑎𝑡𝑡𝑚𝑒𝑡𝑒𝑟 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 𝑖𝑠 𝑡𝑒 𝑡𝑜𝑡𝑎𝑙 𝑝𝑜𝑤𝑒𝑟 𝑐𝑜𝑛𝑠𝑢𝑚𝑒𝑑 𝑏𝑦 𝑡𝑒 3 ø 𝑙𝑜𝑎𝑑.
𝑾𝟏 + 𝑾𝟐 = 𝑽𝑳 𝑰𝑳 𝑪𝒐𝒔 (𝟑𝟎 − ø) + 𝑽𝑳 𝑰𝑳 𝑪𝒐𝒔 (𝟑𝟎 + ø)
= 𝑽𝑳 𝑰𝑳 [𝑪𝒐𝒔 (𝟑𝟎 − ø) + 𝑪𝒐𝒔 (𝟑𝟎 + ø)]
= 𝑽𝑳 𝑰𝑳𝟐 𝑪𝒐𝒔 𝟑𝟎 𝑪𝒐𝒔ø.
= 𝑽𝑳 𝑰𝑳 𝟐. 𝟑/𝟐.𝑪𝒐𝒔ø
= 𝟑 𝑽𝑳 𝑰𝑳𝑪𝒐𝒔ø. = 𝑬𝒒𝒖𝒂𝒕𝒊𝒐𝒏 𝒇𝒐𝒓 𝒕𝒐𝒕𝒂𝒍 𝒑𝒐𝒘𝒆𝒓 𝒊𝒏 𝒕𝒉𝒓𝒆𝒆 𝒑𝒉𝒂𝒔𝒆 𝒍𝒐𝒂𝒅.
𝑾𝟏 − 𝑾𝟐 = 𝑽𝑳 𝑰𝑳 𝑪𝒐𝒔 (𝟑𝟎 − ø) − 𝑽𝑳 𝑰𝑳 𝑪𝒐𝒔 (𝟑𝟎 + ø)
= 𝑽𝑳 𝑰𝑳 [𝑪𝒐𝒔 (𝟑𝟎 − ø) − 𝑪𝒐𝒔 (𝟑𝟎 + ø)]
= 𝑽𝑳 𝑰𝑳 𝟐. 𝑺𝒊𝒏 𝟑𝟎.𝑺𝒊𝒏ø
= 𝟐. 𝟏/𝟐. 𝑽𝑳 𝑰𝑳 . 𝑺𝒊𝒏ø
= 𝑽𝑳 𝑰𝑳 . 𝑺𝒊𝒏ø
𝑾𝟏− 𝑾𝟐
𝑾𝟏+ 𝑾𝟐 =
𝑽𝑳 𝑰𝑳 .𝑺𝒊𝒏ø
3𝑽𝑳 𝑰𝑳𝑪𝒐𝒔ø =
1
3tan
= 𝐭𝐚𝐧−𝟏[ 𝟑(𝑾𝟏− 𝑾𝟐𝑾𝟏+ 𝑾𝟐
)]
𝑯𝒆𝒏𝒄𝒆 𝒑𝒐𝒘𝒆𝒓 𝒇𝒂𝒄𝒕𝒐𝒓 𝒄𝒐𝒔 𝒄𝒂𝒏 𝒃𝒆 𝒄𝒂𝒍𝒄𝒖𝒍𝒂𝒕𝒆𝒅.
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 11
PROCEDURE
1. Connections are made as shown in the circuit diagram
2. Keep the autotransformer at minimum position
3. Adjust the autotransformer till the voltmeter reads rated voltage of the load.
4. Take the corresponding v/m, a/m and w/m readings.
5. Adjustthe load for different readings
6. Tabulate the readings and calculate the power and power factor
TABULATION
Sl no V I W1 W2 W1+W2 W2-W1 𝑻𝒂𝒏
𝒄𝒐𝒔
RESULT:
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 12
CALIBRATION OF WATTMETER USING VOLTMETER AND AMMETER. AIM
To calibrate the given single phase wattmeter using standard voltmeter and ammeter. Draw the error curve.
CIRCUIT DIAGRAM
APPARATUS REQUIRED:-
THEORY
Calibration of wattmeter means standardizing of meter and finding out the error. A wattmeter is a device
that is constructed out of pressure coil and current coil. The pressure coil is connected in parallel with the
circuit, and current coil in series with the circuit. The current coil has low resistance connected in series with the
ammeter.
Sl No Apparatus Specification Quantity
1
2
3
4
Voltmeter
Ammeter
Wattmeter
Lamp load
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 13
There are Induction type (used in AC measurements only) and Dynamometer type wattmeter (used in
both AC & DC measurements).
𝑅𝑒𝑐𝑜𝑟𝑑𝑒𝑑 𝑝𝑜𝑤𝑒𝑟 = 𝑤𝑎𝑡𝑡𝑚𝑒𝑡𝑒𝑟 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 𝑥 𝑚𝑢𝑙𝑡𝑖𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑓𝑎𝑐𝑡𝑜𝑟 𝑜𝑓 𝑤𝑎𝑡𝑡𝑚𝑒𝑡𝑒𝑟.
𝑀𝑢𝑙𝑡𝑖𝑝𝑙𝑖𝑐𝑎𝑡𝑖𝑜𝑛 𝑓𝑎𝑐𝑡𝑜𝑟
= 𝑆𝑒𝑙𝑒𝑐𝑡𝑒𝑑 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 𝑟𝑎𝑛𝑔𝑒 𝑜𝑓 𝑊/𝑚 𝑥 𝑆𝑒𝑙𝑒𝑐𝑡𝑒𝑑 𝑐𝑢𝑟𝑟𝑒𝑛𝑡 𝑟𝑎𝑛𝑔𝑒 𝑜𝑓 𝑤𝑎𝑡𝑡𝑚𝑒𝑡𝑒𝑟 𝑥 𝑃𝐹
𝑚𝑎𝑥𝑖𝑚𝑢𝑚 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 𝑜𝑛 𝑡𝑒 𝑑𝑖𝑎𝑙 𝑜𝑓 𝑤𝑎𝑡𝑡𝑚𝑒𝑡𝑒𝑟.
𝑇𝑟𝑢𝑒 𝑝𝑜𝑤𝑒𝑟 = 𝑉/𝑚 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 𝑥 𝐴/𝑚 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 ,
𝑠𝑖𝑛𝑐𝑒 𝑡𝑒 𝑙𝑜𝑎𝑑 𝑢𝑠𝑒𝑑 𝑖𝑠 𝑝𝑢𝑟𝑒𝑙𝑦 𝑟𝑒𝑠𝑖𝑠𝑡𝑖𝑣𝑒, 𝑖𝑡𝑠 𝑝𝑓 𝑖𝑠 𝑢𝑛𝑖𝑡𝑦.
%𝑒𝑟𝑟𝑜𝑟 =𝑟𝑒𝑐𝑜𝑟𝑑𝑒𝑑 𝑝𝑜𝑤𝑒𝑟 − 𝑡𝑟𝑢𝑒 𝑝𝑜𝑤𝑒𝑟
𝑟𝑒𝑐𝑜𝑟𝑑𝑒𝑑 𝑝𝑜𝑤𝑒𝑟× 100
PROCEDURE
1. Connect the circuit as shown in figure
2. Checked the connections and given the supply.
3. Adjust the auto transformer upto rated voltage of the meter to be tested
4. Varied the load and taken the corresponding readings. Up to the 120% of the rated current of the meter
to be tested.
5. Calculated the true power, recorded power and % error at the different loads.
6. Plotted the error curve.
TABULATION
RESULT
Sl
No 𝐴/ 𝑚 𝑟𝑒𝑎𝑑𝑖𝑛𝑔− 𝐴𝑚𝑝𝑠
𝑉/𝑚 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 −𝑉𝑜𝑙𝑡𝑠
𝑊/𝑚− 𝑊𝑎𝑡𝑡𝑠
𝑅𝑒𝑐. 𝑃𝑜𝑤𝑒𝑟 𝑊𝑎𝑡𝑡𝑠 𝑇𝑟𝑢𝑒 𝑝𝑜𝑤𝑒𝑟 𝑊𝑎𝑡𝑡𝑠
% 𝐸𝑟𝑟𝑜𝑟
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 14
ENERGY METER CALIBRATION BY DIRECT LOADING
AIM
To calibrate the energy meter by direct loading.
CIRCUIT DIAGRAM
APPARATUS REQUIRED
THEORY
The process of comparing of an instrument with standard or absolute instrument is called calibration.
The energy meter records the energy consumed in KWH. Let 𝑅𝑋 be the number of revolutions of the
disc. 𝐾𝑋 Is the revolution per KWH (meter constant).
Recorded energy=𝑅𝑋 𝐾𝑋 𝐾𝑊𝐻
Sl No Apparatus Specification Quantity
1
2
3
4
5
Voltmeter
Ammeter
Wattmeter
Lamp load
Energy meter
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 15
The true energy=𝑤/𝑚 𝑟𝑒𝑎𝑑𝑖𝑛𝑔 ∗ 𝑡𝑖𝑚𝑒
%error= (𝑟𝑒𝑐𝑜𝑟𝑑𝑒𝑑 𝑒𝑛𝑒𝑟𝑔𝑦 − 𝑡𝑟𝑢𝑒 𝑒𝑛𝑒𝑟𝑔𝑦)/𝑡𝑟𝑢𝑒 𝑒𝑛𝑒𝑟𝑔𝑦 × 100
PROCEDURE
1. Connections are made as per the circuit diagram
2. Keep the autotransformer at minimum position and switch on the supply
3. Adjust the autotransformer to the rated voltage of the energy meter
4. Adjust the load to a suitable value and note the corresponding w/m reading and time taken for 5
revolution of energy meter disc
5. Repeat the step no 4 after increasing the load
6. Tabulate the readings and calculate the %error
OBSERVATION
Sl no v/m in
volt
A/m in
amps
No. of
rev
w/m in
watts
Time in
sec
True
energy
Actual
energy
%error
RESULT
Calibrated the given single phase energy meter by direct loading at UPF and plotted the error curve
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 16
CALIBRATION OF WATTMETER BY PHANTOM LOADING
AIM
To calibrate the given single phase wattmeter by phantom loading at UPF and at 0.5pf lag and plot the error
curve
CIRCIT DIAGRAM
……………….
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 17
APPARATUS REQUIRED:-
THEORY
When current rating of the meter under test is high, a test with actual loading arrangements involves
considerable waste of power. Phantom loading consists of supplying the pressure circuit with required
normal voltage and the current circuit from a low voltage supply. the total power required for testing the
meter with phantom loading is comparatively very small.
OBSERVATION
PF v/m A/m Indicating
reading
watts
Actual reading
watts
Percentage
error= 𝐼𝑅−𝐴𝑅
𝐴𝑅
UPF
0.5
LAG
PROCEDURE
At UPF
1. Connections are made as shown in diagram
2. The rated voltage applied across pressure coil
3. Keep the autotransformer at its minimum position and switch on the power supply.
4. Adjust the autotransformer for various values of current from minimum to maximum
5. Take all meter readings and calculate the percentage error
Sl No Apparatus Specification Quantity
1
2
3
4
Voltmeter
Ammeter
Wattmeter
Lamp load
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 18
6. Plot error curve
At 0.5pf lag
1. Connect the pressure coil across N&Y and CC in R phase
2. Repeat the same procedure mentioned above
3. Plot the error curve
RESULT
The given single phase wattmeter is calibrated at UPF and 0.5 lag by phantom loading
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 19
MEASUREMENT OF INDUCTANCE
AIM
To measure the inductance and power factor of the given coil.
CIRCUIT DIAGRAM
MEASUREMENT OF RESISTANCE OF THE COIL
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 20
APPARATUS REQUIRED:-
CIRCUIT TO FIND RESISTANCE OF THE COIL
THEORY
Inductance is the property of a circuit or a component to oppose the change in current through it. An
induction coil has a small resistance and an inductive reactance.
XL = 𝒁𝟐 − 𝑹𝟐
But XL=2πfL
I.e., L= 𝑋𝐿
2𝜋𝑓
Power factor of the coil=𝑃 𝑉𝐼
PROCEDURE
1. Connections are made as shown in diagram
2. Keep the autotransformer in the minimum position and switch on the supply
3. Adjust the autotransformer into rated voltage
4. Note all meter readings
5. Tabulate the reading and calculate the inductance and pf of the coil
PROCEDURE FOR FINDING RESISTANCE OF THE COIL
1. Connections are made as shown in diagram
2. Keep the autotransformer in the minimum position and switch on the supply
3. Adjust the autotransformer for different ammeter readings up to the rated current of the coil
4. Note all meter readings
5. Tabulate the reading and calculate the resistance of the coil
Sl No Apparatus Specification Quantity
1
2
3
4
Voltmeter
Ammeter
Wattmeter
Inductive coil
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 21
TABULATIONS
Sl no Volt
meter
reading
in volt
Ammeter
reading
in
ampere
Wattmeter
reading P
in watts
Z=V/I
ohm
R ohm
XL
= 𝑍2 − 𝑅2
ohm
L=
XL 2𝜋𝑓 Henry
Pf= 𝑃
𝑉𝐼
RESULT
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 22
RLC SERIES CIRCUIT
AIM
To determine the Resistance, Reactance and impedance of RLC series circuit.
CIRCUIT DIAGRAM
APPARATUS REQUIRED
SI No Instrument specification QUT
1
2
3
4
5
6
AMMETER
VOLTMETER
RHEOSTAT
CHOKE
CAPACITOR
AUTOTRANSFORMER
1NO
1 EACH
1 NO
1 NO
1NO
1 NO
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 23
THEORY
In the RLC circuit , let I be the current through the circuit . let V be the applied voltage and VR,VL,and
VL be the voltage across resistor , inductor and capacitor respectively.
R=(VR / I)
XL=(VL/I)
XC=VC/I
V=IZ
=I (𝑅2+(XL-XC)
2)
Z is called impedance of the circuit.
Power factor cos ∅=(W/VI)=R/Z
PROCEDURE
1. Connections are given as per the diagram.
2. The experiment is started by keeping the autotransformer at minimum position.
3. Then adjust the autotransformer so as to vary the input voltage so the current trough the circuit also
changed.
4. All meter readings are to be takent at this condition.
5. Then repeat the procedure by changing autotransformer.
6. Take voltage and current in each case.
7. Calculate all parameters from this reading
TABULATION
SI
no
V
VOLT
I
AMPS
W
WATT
VR
VOLT
VL
VOLT
VC
VOLT
XL
OHM
XC
OHM
R
OHM
RESULT
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 24
CALIBRATION OF ENERGY METER BY PHANTOM LOADING
AIM
To calibrate the given single phase wattmeter by phantom loading at UPF and at 0.5pf.
CIRCUIT DIAGRAM
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 25
APPARATUS REQUIRED:-
THEORY
When current rating of the meter under test is high, a test with actual loading arrangements involves
considerable waste of power. Phantom loading consists of supplying the pressure circuit with required
normal voltage and the current circuit from a low voltage supply. the total power required for testing the
meter with phantom loading is comparatively very small.
Recorded reading=5
𝑡X
3600
𝑁KWH
Actual reading=power X time KWH
PROCEDURE
At UPF
1. Connections are made as shown in diagram
2. The rated voltage applied across pressure coil
3. Keep the autotransformer at its minimum position and switch on the power supply.
4. Adjust the autotransformer for various values of current from minimum to maximum
5. Take all meter readings and time taken for 5revolution of E/M disc
6. Plot error curve
At 0.5pf lag
1. Connect the pressure coil across N&Y and CC in R phase
2. Repeat the same procedure mentioned above
3. Plot the error curve
Sl No Apparatus Specification Quantity
1
2
3
4
Voltmeter
Ammeter
Wattmeter
Lamp load
ELECTRICAL MEASUREMENT LAB DEPARTMENT OF EEE
MA’DIN Polytechnic college 26
TABULATION
PF v/m A/m Time for
5rev of
E/M disc
Recorded
Energy=
5
𝑡×
3600
𝑁
KWH
Actual
Energy=
𝑉𝐼 cos ∅/1000
Error
𝑅𝑃 − 𝐴𝑃
%error= 𝑅𝑃 − 𝐴𝑃
𝑅𝑃
UPF
0.5
LAG
RESULT
The given single phase energy meter is calibrated at UPF and 0.5 lag by phantom loading