LEARN ELECTRICAL

ELECTRICAL POWER TOOLS (1) DRILL MACHINE Hand-Held Bench Type Drill Machine (2) GRINDER MACHINE Angle Type Straight Grinder Machine Bench Type Grinder Machine  (3) SOLDERING IRON (4) HEAT GUN (5) CUT-OFF MACHINE (6) DEMOLITION HAMMER (7) ELECTRICAL AIR BLOWER Hand-Held Portable (8) HYDRAULIC CRIMPING TOOL (for lugs punching) Page No. 15

CAPACITANCE The ratio between electric charge and voltage Q/V is called capacitance. The unit of capacitance is ‘Farad’. Electric charge (Q) unit is coulomb. The farad (F) is a very large unit and in practice capacitance are usually measured in uF (Micro Farad) or (Pico Farad) pF. 1 Farad                 =             1/1000 000          =             10 uF Capacitor: The component possessing the property of capacitance is called capacitor. there are tow types of capacitor; (1)Fixed Capacitor (2) Variable capacitor Page No. 14

RESISTANCE Conductor: A material which gives up free electrons easily and offer little opposition resistance to flow of current is called conductor. Example: Gold, Silver, Copper, Aluminum, Iron, Brass Insulator: A material which does not give up free electrons easily and offers great opposition resistance to flow of current is called insulator. Example: Glass, Rubber, Oil, Porcelain, Ceramic Resistance: (R) Opposition offered to the flow of electrons in any substance is called Resistance, it is denoted by Ω and measured in ohm.    All materials have resistance, which we used as a conductor in wires and cables. Two materials copper and aluminum are using as a conductor in wires. Electrician must follow the law of resistance during lying and installation of a wire or cable. LAW OF RESISTANCE 1.        The resistance of a conductor varies directly as its length. Example:       ...

WIRE AND CABLE Parts of a Cable 1.     Conductor 2.     Insulator 3.     Outer Sheath The construction and material are determined of a cable by three main factors: 1.        Working Voltage determining the thickness of the insulation. 2.        Current Carrying capacity determining the cross-sectional size of the conductor(s).         Environmental Conditions such as temperature, water, chemical of sunlight exposure, and mechanical impact, determining the form and composition of the outer cable jacket. Types of Conductor: 1.     Solid 2.     Stranded – Circular round Conductor 3.     Stranded – Circular Compacted  conductor 4.     Stranded – Sector shaped conductor 5.     Flexible conductor        Extra-f...