Microwaves and How They Work
Microwaves are a form of high frequency radio
waves similar to those used by a radio, including
AM, FM and CB. They are similar to a television
where the radio waves are converted to a picture
on the screen. However, microwaves are much
shorter than radio waves; approximately twelve
centimetres wave length. Electricity is converted
into microwave energy by the magnetron tube
(which is the heart of the microwave oven).
From the magnetron tube, microwave energy is
transmitted to the oven cavity through a small
plastic covered piece. The microwaves are
converted to heat in the food. The microwaves
enter from the outside of the food and travel
through the food losing half of their power every
two to three centimetres. Continued cooking to
the centre occurs by conduction.
Although pacemakers used to be affected by
microwaves (as well as by other radio waves),
they are now shielded and are not bothered by
these interferences. This allows people with
pacemakers to sit calmly by their radio or
television and cook with microwave ovens.
When microwaves come in contact with a
substance, any one or combination of three
things may occur.
They can be:
1. REFLECTED
2. TRANSMITTED
3. ABSORBED
Reflection:
Metal substances REFLECT microwave energy
and because there is no absorption, there is no
heating. This is why the oven interior is either
stainless steel or epoxy-coated steel. This
ensures that the microwaves are kept inside the
cavity and evenly distributed throughout the
food with the help of the turntable.
Transmission:
Such substances as paper, glass and plastic
TRANSMIT microwave energy and do not become
hot except from food. Because these substances
do not reflect or absorb microwave energy, they are
ideal materials for microwave cooking containers.
Absorption:
Food contains moisture and will ABSORB
microwave energy, which causes the moisture
molecules within the food to vibrate at an
incredible rate (2,450,000,000 times per second).
Friction, created by the vibration, produces heat
energy which is conducted throughout the food.
Circuits
Your microwave oven should be operated on a
separate 10 A circuit from other appliances.
Failure to do this may cause the power board
fuse to blow, and/or food to cook slower. Do not
insert higher value fuse in the power board.
Earthing Instructions
This microwave oven must be earthed. In the
event of an electrical short circuit, earthing
reduces the risk of electric shock by providing
an escape wire for the electric current. This
microwave oven is equipped with a cord having
an earthing wire with an earthing plug. The plug
must be plugged into an outlet that is properly
installed and earthed.
WARNING — Improper use of the earthing plug
can result in a risk of electric shock.
WE CERTIFY THAT THIS MICROWAVE
OVEN HAS BEEN INSPECTED AND
COMPLIES WITH THE REQUIREMENTS OF
REGULATION 3, SUBCLAUSE(2), OF THE
MICROWAVE OVENS REGULATIONS 1982.
(This statement applicable only to New Zealand.)
We certify that this microwave oven has been
inspected and complies with the safety
requirements of government notice 466 of
March 1981, and complies with the Radio
Regulation of government notice 587 of March
1986.
(This statement applicable only to South Africa.)
WARNING
a) The door seals and door seal areas should be
cleaned with a damp cloth. The appliance
should be inspected for damage to the door
seals and door seal areas and if these areas
are damaged the appliance should not be
operated until it has been repaired by a qualified
service technician trained by the manufacturer.
b) It is hazardous for anyone other than a
competent person to carry out any service
or repair operation that involves the removal
of a cover which gives protection against
exposure to microwave energy.
c) If the supply cord of this appliance is
damaged, it must be replaced by a qualified
service technician with the special cord
available only from the manufacturer.
d) Before use, the user should check that
whether the utensils are suitable for use in
microwave ovens.
e) Liquids or other foods must not be heated in
sealed containers since they are liable to
explode.
f) Only allow children to use the oven without
supervision when adequate instructions
have been given so that the child is able to
use the oven in a safe way and understands
the hazards of improper use.
3
