Look carefully at the list of common electrical
appliances in the table at the bottom of this page and answer a couple of basic questions
about them.
Consider the properties of each appliance and place a tick or cross in each column so that you can look
for a pattern in the properties.
Motor Presence
Motors
produce movement. If a motor is present you should hear a whirring sound.
Do not dismantle any appliance to see if it has a factor - ASK!
Heat Production
Heat is always produced in machines, whether
it is wanted or not!
It is pretty easy to decide whether heat
is produced by design (eg the immersion heater is designed to heat water)
but it is not so easy to see whether heat is produced as a by-product.
You will probably need to have the appliance
switched on for a while before you can find this out, or ask someone
who uses it a lot.
Be careful you don't burn yourself. (You
could indicate how much heat is produced in the column provided).
Does an appliance that produces heat by
design, also produce some by-product heat? (i.e. heat where it is not
made use of ~ wasted heat).
Look to see whether there is some feature
of the machine to cut down by-product heat loss or some feature to facilitate
the dispersion of by-product heat loss (e.g. fins).
Power Classification
We are going to classify appliances as
high, medium or low power by the type of fuse they need. An appliance
will have details of the power rating written on it somewhere.
Low powered appliances only need
a 3A (3 amp) fuse. They have power ratings of 720 W (720 watts) or less.
Medium powered appliances require
a 5 A (5 amp) fuse (although a 13A fuse is often fitted). They have
power ratings of between 720 W and 1200 W (1.2 kilowatts - 1.2 kW).
High powered appliances must have
a 13A (13 amp) fuse fitted. They have power ratings of up to 3.2 kW.
Questions
- Look carefully at the appliances you
have classified as high power. Study the columns that you have ticked
for each one. Can you see any pattern?
- Look carefully at the appliances you
have classified as low power. Study the columns that you have ticked
for each one. Can you see any pattern?
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Name of Electrical Appliance
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Motor present
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Heat produced (by design)
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Heat produced (as an unwanted by-product)
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Light produced
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Power Rating (high, medium, low)
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cassette player
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computer
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cooker
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freezer
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fridge
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fridge/freezer
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immersion heater
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iron
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kettle
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lamp
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microwave cooker
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mixer
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radio
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spin drier
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television
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toaster
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tumble drier
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vacuum cleaner
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video recorder
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washing machine
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