Sharp R-890SLM operation manual Heating Category, How Your Oven Works, Microwave output power

HEATING CATEGORY

		Microwave output power
		in	Watts	(based		on
		international
		(IEC 60705) standard).
		Letter representing				the
		oven heating category.
Microwave Symbol.
OVEN	Less heating time required
	600 700 800 900 1000 Watts
OUTPUT
POWER
	More heating time required
OVEN	Less heating time required
	A	B	C	D	E
OUTPUT
CATEGORY
	More heating time required

The heating category (a letter A to E) developed by MAFF (Ministry of Agriculture, Fisheries and Food) with microwave oven and food manufacturers indicates the ability of the oven to heat small quantities of food (up to 500g [1lb 2oz]). It does not represent the general performance of the oven.

Food packs carry cooking instructions for heating categories A to E. Follow instructions for the letter corresponding to the oven’s heating category. The higher the output power and heating category of the oven the less heating time is required as shown opposite.

HOW YOUR OVEN WORKS

Microwaves are energy waves, similar to those used for TV and radio signals.

Electrical energy is converted into microwave energy, which is directed into the oven cavity via a waveguide. To prevent food and grease entering the wave guide it is protected by the waveguide cover.

Microwaves cannot pass through metal, because of this the oven cavity is made of metal and there is a fine metal mesh on the door. During cooking the microwaves bounce off the sides of the oven cavity at random.

Microwaves will pass through certain materials, such as glass and plastic, to heat the food. (See ‘Suitable Cookware’ on page 32).

Water, sugar and fat in food absorb microwaves which cause them to vibrate. This creates heat by friction, in the same way your hands get warm when you rub them together.

The outer areas of the food are heated by the microwave energy, then the heat moves to the centre by conduction, as it does in conventional cooking. It is important to turn, rearrange or stir food to ensure even heating.

Once cooking is complete, the oven automatically stops producing microwaves.

Standing time is necessary after cooking, as it enables the heat to disperse equally throughout the food.

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