Page 122 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

4 Record the voltage readings in Standard voltmeter and Old voltmeter which to be calibrated.

5 Make the connections for calibration of MI Voltmeter as per circuit diagram.
6 Check the connections and set the auto transformer knob to zero position.
7 Switch ON the supply, slowly increase the voltage by auto transformer step by step.
8 Record the voltage readings in Standard voltmeter and Old voltmeter which to be calibrated.
9 Make the connections for calibration of PMMC Ammeter as per circuit diagram.

10 Check the connections and keep the load switch in OFF position.
11 Switch ON the DC supply and increase the lamp load step by step.
R
R
x
2

R
12 Record the current readings in Standard ammeter and Old ammeter which to be calibrated.
R
1 3
R
13 Make the connections for calibration of MI Ammeter as per circuit diagram, and repeat the steps 10 to 12
R 2 .R
x
3
R
14 Calculate the percentage error in PMMC & MI meters to be tested as per the formula
1
Where:
V V I I
Percentage errror I S 100 or T S 100
V S I S
T = Test value of voltage OR current recorded in meter to be tested.
S = Standard value of voltage OR current recorded in standard meter
Tabular column:
Calibration of PMMC Voltmeter:
Sl.No Standard voltage (V ) Test voltage (V ) Percentage error
TR RE 100 T
S
TE

Calibration of MI Voltmeter:
Sl.No Standard voltage (V ) Test voltage (V ) Percentage error
S
T

Calibration of PMMC Ammeter:

Sl.No Standard current (I ) Test current (I ) Percentage error
S T

105

CITS : Power - Electrician & Wireman - Exercise 51