ABSTRACT
Drawing used to calculate impedance in an a.c. circuit
Internal resistance
Resistance within a cell or cells
Kilogram unit of mass kW True power (×1000) kVA Apparent power (×1000) kVAr Reactive power (×1000) Load Object to be moved Load The current drawn by electrical equipment
connected to an electrical circuit Mutual induction
Effect of the magnetic field around a conductor on another conductor
Magnetic flux Quantity of magnetism measured in Webers Magnetic flux density
Is the density of flux measured in Webers per metre squared or Tesla
Newton Pull of gravity (measurement of force) On-Site Guide Publication by the IEE containing
information on electrical installation Ohm Unit of resistance Overload current
An overcurrent flowing in a circuit which is electrically sound
Percentage efficiency
The ratio of input and output power multiplied by 100
Power Energy used doing work Pressure Continuous force Primary winding
Winding of transformer which is connected to a supply
Perimeter Outer edge Potential difference
Voltage difference between conductive parts
Prospective short circuit current
The maximum current which could flow between live conductors
Prospective fault current
The highest current which could flow in a circuit due to a fault
Protective device
A device inserted into a circuit to protect the cables from overcurrent or fault currents
Resistor Component which resists the flow of electricity
Resistance Opposition to the flow of current Resistivity Property of a material which affects its
ability to conduct Rectangle Four-sided figure with right angles Space factor Amount of usable space in an enclosure Secondary winding
Winding of transformer which is connected to a load
Self-Induction Effect of a magnetic field in a conductor Series Connected end to end Thermoplastic Cable insulation which becomes soft when
heated and remains flexible when cooled down
Transpose Change order to calculate a value Triangle Three-sided object Thermosetting Cable insulation which becomes soft when
heated and is rigid when cooled down Transformer A device which uses electromagnetism to
convert a.c. current from one voltage to
Voltage drop Amount of voltage lost due to a resistance Volume Space occupied by a mass Watt metre Instrument used to measure true power Waveform The shape of an electrical signal Work Energy used moving a load (given in
Newton metres or joules) Phasor Drawing used to calculate electrical values
