Page 74 - Electrician - TT (Volume 1)

ELECTRICIAN - CITS

• Polarity: - The positive terminal of the battery is connected to the positive of supply and negative terminal is
connected to the negative terminal of the supply.
• The vent plug: -Should be kept loose for the liberation of gas during charging.
• The battery terminal should be kept clean. A thin layer of Vaseline or petroleum jelly should be applied over
them to prevent corrosion.
• A battery: - should not be charged or discharged at high rate continuously
• A battery: - should never be discharged beyond 1.8V, otherwise the lead sulphate changes into an insoluble
salt.
• The battery: - should be recharged as soon as possible after discharge.
• The battery charging room: - should be well ventilated because the gases liberated during charging are
flammable in and explosive nature.
• A discharge battery: - should not be tested with a high rate discharge cell tester. It should be applied to a
charged cell for not more than 10s.

• The Specific gravity: - of the electrolyte should be checked before and after a battery is put on charge.
• Preparing the electrolyte: - the acid should always be added drop by drop into the water and not vice versa.
• If the battery: - is not being used for long period, then it should be put on trickle charge.
Topping up

If the level of the electrolyte on the surface of the plate is less than 10 to 15 mm then some distilled water should
be added in the cell. This process is known as topping up.
Trickle charging
The continuous charging of a battery at low rate for keeping the battery ready in good working condition is called
trickle charging. This value of charging current is approximately 2% of the full charging current of the battery.
Testing of battery
Preparation of Electrolyte

• The electrolyte for the cell can be prepared by adding sulphuric acid to distilled water drop by drop and not
vice-versa (AAA principle)
• A glass rod should be used for stirring the electrolyte

• While preparing electrolyte the sp. Gravity decreases as the temperature increases. Therefore, the electrolyte
should be allowed to cool to room temperature before filling
Specific. Gravity.....1.200-1.300
Use of hydrometer &high rate discharge cell tester

Indication of fully charged cell,
• Color of plates
• Specific gravity (increases from 1.180 to1.280)
• Gassing occur on both plates
• Voltage/cell (rises from 1.8 to 2.2V)

• High rate discharge cell tester-The voltage of fully charged cell is tested on load
Hydrometer
Main parts,
Rubber bulb, Glass tube, Float, Flexible rubber tube.

The specific gravity of electrolyte is measured with a hydrometer
• It measure relative density of electrolyte.

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CITS : Power - Electrician & Wireman - Lesson 13-19 CITS : Power - Electrician & Wireman - Lesson 13-19