BUYING A GENERATOR: A DUMMY’S GUIDE TO:

Step 1: Decide whether you want to link up your generator into your electricity system, or
whether you will make do with extension cables. If you link up with the electricity system, it is
very important that this should be done by a reputable electrician, and you would generally also
need a larger generator than if you are going to link only critical appliances to the generator by
extension cables.

Step 2: Decide which appliances you have to run simultaneously when there is an outage, and
whether you can rotate the appliances, i.e. apply power management – for instance, can you run
only the TV and lights at one time, or the fridge on its own at another time. Only the very large
(expensive!) generators would be able to run several high wattage appliances at the same time.

Step 3: Determine the highest wattage that you might require at any one time. Most appliances
show the wattage requirements on a plate on the appliances. Ten 100-watt globes will require a
1000 watt generator. Appliances with electric motors (e.g. fridges, washing machines,
microwave ovens, hair dryers) have a much larger “starting” wattage requirement (up to three
times the “running” wattage requirement), so you need both the running and the starting wattage requirement.

Some rough examples:
Running wattage req. Starting wattage req.
Fridge/freezer 1000 2200
Microwave 800 1000
Washing machine 1200 3000
TV 400 0

Air conditioners, geysers, and clothes dryers generally have a very high wattage requirement. If
you use warm water sparingly, your geyser’s water will remain warm for up to 24 hours in
summer, but less in winter.

Step 4: Use the above information to decide on a generator: This will be determined by three
things:
• Whether you will also be running sensitive electronic equipment such as a TV and
computer on the generator, in which case it must have an Automatic Voltage Regulator
(AVR).
• The rated output of the generator, i.e. the output that the generator can normally produce
(which is normally about 80% of maximum output).
• The maximum output, i.e. the maximum it can produce to start up electric motors. Don’t
run the generator on maximum for more than 10-20 minutes.

For instance, if you only want to run your TV, some lights, microwave and fridge, and if you are
prepared to rotate the equipment, then you will need a smaller generator, but probably not less
than about 2.5 kVA maximum output (i.e. 2500 Volt*Ampere, which is the same as 2500 Watt).

But if you want to run your washing machine, for instance, you will have to buy a machine with
a maximum kVA of higher than 3.0 kVA, depending on your specific appliance.
If you are going to buy a reputable generator with AVR, don’t expect to pay much less
than R4000-R5000. These generators will also start with a recoil starter – electric starters add to the cost again.

But please be advised – we take no responsibility for any damage that you might suffer in
setting up or using your system. The information in this newsletter is provided simply to put you
on the right track, and you should get more professional advice from the experts where you
purchase the generator, or from an electrician.

A reputable firm that you might want to contact in regard to purchasing a generator or for
further advice, is the Lawnmower Clinic tel (012) 323 1833. They sell a wide range of Briggs
and Stratton and Honda generators. You could also consult their website at
http://www.lawnmowers.co.za/.

This article was written by one of our customers, and published in the "Moreleta Kloof Estate Newsletter - January 2008".