MEASURING ELECTRICAL ENERGY

Radio Record, Volume I, Issue 32, 24 February 1928, Page 11

MEASURING ELECTRICAL ENERGY

Current supply from the mains is measured in kilowatt-hours, or legal units. A watt is one ampere flowing at one volt for one hour. A thonsand watt-hours make one unit or kilowatthour. Now this thousand watt-hours may be used up in many different ways, the whole thousand being consumed in one hour, or ten watts may be used per hour, end the unit (costing an average of 6d.) will then last for 100 hours. An ordinary 60-candle power lamp uses 60 watts or watt-hours, so that to consume one unit it will give light for nearly 17 hours. ‘I'he watt is the product of the amperes flowing and the volts applied irrespective of time. Thus 1f 4 volts are driving half an ampere through a valve filament, the power being used is 2 watts. " Many electrical meters have two additional small dials showing tenths and hundredths of a unit, each division on the latter representing ten watts or watt-hours. Meters register kilo-watt-hours and fractions thereof. |