Page 238 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

Note : Reset switch (S4) is used to reset the charger, when any fault occurs and the charger is cut
off. The switch (S1) for ON/OFF.
9 Connect the ON/OFF switch (S1) to the input of AC main supply.
Note : Normally a fully charged lead acid battery voltage 2.1 V/cell, During on charge ,and can be
increased up to 2.7 V/cell .The voltage of a battery is multiple of the number of cells in that battery.
The voltage on Fully discharged condition is 1.8 V.
10 Connect the diodes neon lamps, fuses, capacitor, resistor, buzzer, low voltage lamp in correct position as in
the circuit.
11 Solder all PCB connection neatly and clean the PCB, without making any short circuit.
12 Set the auto transformer (X2) is in zero level position, before charging the battery.

13 Keep the switches S1,S2 & S5 on open position .
14 Connect the battery to the charger output terminal (positive terminal to the battery positive pole and negative
terminal to the battery negative pole )and close the switch S3.
15 Check the readings in voltmeter which is connected through diode D9 and switch S3.

Note : If the battery is connected in wrong/reverse polarity, then the diode will block the battery
voltage and no reading in voltmeter. Correct the battery polarity by charging the connection to read
the volt meter.
16 Close the main ON/OFF switch (S1) by keeping the zero position of an autotransformer (X2) and neon lamp
(N1) and Lamp (L1) will indicate ‘ON’.
17 Vary the setting of Auto transformer slowly from zero position until the voltmeter shows the reading nearer to
the voltage of battery to be charged.
18 Switch ‘ON’ the charging switch (S2) and increase the voltage by varying auto transformer till, the required
charging current (5 Amp) is displayed by the ammeter.
19 Leave the charger on to charge the battery to the required level.
Note : If the battery is fully charged automatic cut-off circuit will switch ‘OFF’ the supply to the
battery, and automatically switch ‘OFF’ the charging current which flows through potentiometer
VR1 , to cut off relay RL1.
When the battery is fully charged the current through the potentiometer increases and relay RL1
is energised through diode D7 and D8, and the pole of relay RL1 (ca) is connected to N/O contact
which will cut off main A.C supply to auto transformer X2 and switch on the error indicator buzzer
and the warning neon ‘N2’ lamp.
20 Switch ‘OFF’ the buzzer by the switch (S5).
Note : The error indicator neon lamp (N2) and the buzzer stays on till the charger is reset.
21 Press the reset switch (S4), only, if the process to be continued once again.

Note : If the reset switch is pressed without correcting the problem which activated the cut off and
again it will operate instantly. To reset the charger, the reset button (S4) to be pressed for about one
second, only to let the capacitor C1, discharge.
The following precautions to be followed when charging the battery.
1 The level of electrolyte should be about 1.2 cm above the plates.
2 Add distilled water to electrolyte if the level of electrolyte is low (acid should not be added to the electrolyte).
3 Charge the battery continuously unless the battery temp. exceeds 37° C stop charging for some time to cool
down the battery.

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CITS : Power - Electrician & Wireman - Exercise 93