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Looking for Trends in the Power of Electrical Appliances

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

  1. 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?
  2. 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?

 

Name of Electrical Appliance

Motor present

Heat produced (by design)

Heat produced (as an unwanted by-product)

Light produced

Power Rating (high, medium, low)

cassette player

 

 

 

 

 

 

 

 

 

 

computer

 

 

 

 

 

 

 

 

 

 

cooker

 

 

 

 

 

 

 

 

 

 

freezer

 

 

 

 

 

 

 

 

 

 

fridge

 

 

 

 

 

 

 

 

 

 

fridge/freezer

 

 

 

 

 

 

 

 

 

 

immersion heater

 

 

 

 

 

 

 

 

 

 

iron

 

 

 

 

 

 

 

 

 

 

kettle

 

 

 

 

 

 

 

 

 

 

lamp

 

 

 

 

 

 

 

 

 

 

microwave cooker

 

 

 

 

 

 

 

 

 

 

mixer

 

 

 

 

 

 

 

 

 

 

radio

 

 

 

 

 

 

 

 

 

 

spin drier

 

 

 

 

 

 

 

 

 

 

television

 

 

 

 

 

 

 

 

 

 

toaster

 

 

 

 

 

 

 

 

 

 

tumble drier

 

 

 

 

 

 

 

 

 

 

vacuum cleaner

 

 

 

 

 

 

 

 

 

 

video recorder

 

 

 

 

 

 

 

 

 

 

washing machine

 

 

 

 

 

 

 

 

 

 

 

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