Working of Microwave Oven

In microwave oven, magnetron is present inside a strong metal box. So, when the food is placed inside the chamber and timer is switched on, a signal is sent to magnetron to emit microwaves and simultaneously the turn table also starts turning.

The following figure lists the steps occurring after the cooking start:

1. The electricity is provided to the magnetron from the power outlet. It converts the electricity into high - powered, 12cm (4,7 inch) radio waves. 
2. Three waves are blasted by the magnetron through a channel into the food compartment. This channel is called a wave guide. 
3. The food which is present on the turntable, spins a slowl round so it can be cooked evenly by the microwaves. 
4. The water molecules are contacted by the micro waves. Then the water molecules start vibrating against each other at a very high speed generating heat. 

It is known that vibrating molecules emit heat. So, faster the molecules vibrate the quicker the food will get heated up. Therefore, we can say that the molecules present in the food cause rapid heat as Microsoft waves pass on their energy to them. 

Parts of Microwave Oven

Microwave oven consists various parts due to which it's functioning takes place some of the parts are shown in the image given below :

Parts of microwave oven 

The following figure lists parts of microwave oven :

Parts of microwave oven 

Power Supply 

• High voltage transformer : It changes a high voltage power source which passes energy to the magnetron. It also drives filament for magnetron. 
• High voltage capacitor : It is directly connected to the transformer, magnetron and via a diode to the chassis.
• High voltage diode : It is used to sustain high voltage surges in Microwave circuit. 

Microwave Generation 

Is dependent on the following :

• Magnetron : Converts high-voltage electric energy to microwave radiation. 
• Waveguide : Controls the direction of the micro waves moving in the cooking chamber. It is done by confining the space of the releasing microwaves from the magnetron 

Cooking Cavity 

A cooking cavity of a microwave oven consists:

• Cooking chamber : It confines the output radiation so that food can get heated up. 
• Cavity lamp : It is given to see the progress of food being cooked inside. 
• Turntable motor : It is used to format even spread of heat as it rotates the food. 

Control Panel 

Microwave oven uses either a digital control panel or an analog dial -type label for operation. The following figure lists the features present in the control panel:

Features of microwavce oven 

Other Parts 

The following figure lists the other essential parts present in the microwave oven :

Blower fan 

• It is used to exhaust the hot air to maintain temperature of magnetron. 

Stirrer fan 

• It is used to disperse the microwave inside the oven 
• It prevents dirt and grease from entering the Waveguide. 

Grill 

• It is used for grilling the food. 
• It reduces the actual cooking time of food by pressing -heating the oven before putting any food. 

Interlocks 

• It is used to stop the microwave oven from working if any of the 2 or 3 locks are not locked properly. 

Type of Microwave Oven

Food places inside the oven could be grilled/baked/cooked. To perform all these process there are generally, three categories of microwave ovens available. The following figure lists these ovens:

In solo models, micro waves are produced by only a single magnetron. 
They can be utilized for cooking and heating or reheating purposes, but they are incapable of performing operations such as roasting and baking. 
These models are the basic models in Microsoft wave ovens. 

In grill models, the microwave ovens are provided with heating coils that induces a grilling or roasting process. 
Its microwave function is turned off, when the grill function is used. 
A brown layer is created by the grilling process on the surface of the food article. 

In conventional model, there is a micro function, the coils for grilling and heaters with a blower to bake the food. 
It has an advantage, either all the function are used independently or in combination to suit the cooking needs.
The cavity temperature is controlled using a thermostat connected to heaters. 

What is Microwave Oven? / Tips

Due to restriction of movement of the moleculars present in frozen water, heating liquid water through microwave give better results.

There are the most common qttributea related to microwave cooking are:

• Power-The standard wattage for a microwave is between 900 to 1200 watts. For smaller microwaves the wattage range between 600 to 800 watts and can cook items from between two to three minutes. Microwaves with a lower wattage take a longer time to cook when compared to microwaves with a higher wattage. 
• Timing - The correct duration to prevent under -cooking or over -cooking. Timing of cooking depends on following factors :

⭕ Quantity

⭕ Shape and size

⭕Density

⭕Moisture content

⭕Food temperature

⭕Sugar and fat contents
Selection of utensils and cooking methods are also important attributes. 

What is Microwave Oven? / Tips

Microwave are non-ionizing electromagnetic radiation comprising of frequency greater than standard radio waves yet lower than infrared light.  The frequency used in microwaves is one of the industrial, scientific, medical (ISM) bands. There bands are reserved so that they don't interfere with the other important radio services. 

The hot and cold spots present on the food turntable are produced by the interference effect of the microwaves. The turntable or rotating source is used to scatter the heat around the food. Food's properties plays a vital role for cooking it used a particular amount of microwave energy.

Microwave uses the combination of three process to cook the food kept inside it.  The center of the food is mainly cooked by heat conduction as the heat only penetrates about 3.5 to 5 CM into the food. The following figure lists three ways with which heat is transferred into the surroundings:

• Conduction 

Refers to the heatvtrabsfer that occurs across the two medium that are in contact with each other. 

• Convection 

Refers to the heat transfer from a solid surface to a moving fluid at a different temperature.

• Radiation 

Refers to the heat exchange between two or more medium. 

It's defined as the electromagnetic radiation in the wavelength range. 

What is Microwave Oven

It is small kitchen appliance that is used for heating and cooling the food. The food is heated by the microwave radiations which is passed through it. It was inverted by Percy Spencer, an American self -taught engineer from Holland, Maine. While he was experimenting on an active reader set, it came to his notice that the microwaves generated by the reader set melted the candy bar present in his pocket. He then realized that the microwaves can also cook food. So, he invented microwave oven for cooking and heating the food.

In microwave oven, the food item is exposed to the radiations of the microwave, in the EM spectrum. The Polar molecule dwelling inside the food particles rotates as the microwave radiation induces the molecules as well as it produces thermal energy. This leads to rapid motion of polarized water molecule in the food, they get pulled back and forth many a times in a span of one second. The rapid motion occurring between the water molecules produces friction, therefore heat is generated. Dielectric heating is the process by which the substances present in food such as water,  absorbs the energy from microwaves. 

Safety Measures for Operating Mixer/Grinder /Juicer

The following figure lists the instructions to be followed for operating a mixer /grinder /juicer:

Read all instructions, operating procedures and safety precautions before use

Do not put the appliance in water 

Unplug the appliance when not in use, before cleaning or taking off parts 

Keep hands, hair and clothing away from moving parts 

Do not operate if cord or plug is damaged 

Avoid the usage of appliance outdoors 

Do not let the cord hang from the edge of table or counter 

Ensure that the appliance cover is clamped securely 

Do not unfasten clamps while the appliance is running 

Remove wire whip,  flat beater or dough hook from mixer before washing 

Do not leave the appliance unattended around children. 

Safety Measures before Using Mixer / Grinder /Juicer

Mixer /Grinder /Juicer are used in every household nowadays but only few people are aware about it's proper placing. The following figure lists the safety measures for placing mixer / grinder /juicer:

Place the appliance on can even platform at a convenient height 

Ensure that the appliance is at least 6 inches away from the wall 

Have sufficient space around the appliances 

Keep away from heat and sunlight 

Do not use an extension cord 

Do not an adapter 

Do not remove ground prong 

Repairing/ Servicing the juicer

The following figure lists the steps of repairing a juicer :

➡️Unplug the juicer

➡️Detach removable parts

➡️Detach the base

➡️Remove the electrical cord

➡️Detach motor from the housing

➡️Remove gears

➡️Use Multimeter to test all electrical parts

➡️Replace the defective parts

Servicing the juicer drive system
The following figure lists the steps of servicing the juicer drive system :

Dissemble the juicer 

⬇️

Access gear assembly

⬇️

Detach gears and spindle 

⬇️

Clean the gears 

⬇️

Check for damaged parts 

⬇️

Replace damaged parts 

⬇️

Apply silicon lubricant to the gears 

⬇️

Reassemble the unit 

Troubleshooting juicer problems

Some frequently occurring juicer problems and their solutions are given in the the following table:

Problems:1. Unit fails to start
Solution :

•  Ensure cord is plugged-in properly 
• Ensure power supply is active 
• Ensure the juicer is switched -on

Problems:2. Motor stopped 

Solution :

• Ensure cord is plugged -in properly 
• Ensure parts are correctly assembled 
• Switch -off the juicer and unplug 
• Let the juicer cool down from overheating 

Problems :3. Juicer noisy 

Solution :

• Switch -off the juicer and unplug 
• Ensure parts are correctly assembled 
• Ensure juicer is on level surface 
• Ensure ingredients are cut properly 

Problems :4. Juicer leaks from top

Solution :

• Switch -off the juicer and unplug 
• Check that the compression silicone is assembled properlyb
• If not, dissemble the juicer 
• Assemble the compression silicone properly 

Problems :5. Discoloration of plastic parts 

Solution :

• Clean the juicer after every use 
• Rub the discoloured parts with cooking oil
• Clean with mild soap 
• Remove and clean silicone parts separately 

Problems :6. Mold in silicon parts 

Solution :

• Remove and clean silicon parts separately 

Problem :7. Strainer damaged 

Solution :

• Refer to instruction manual for proper usage 
• Avoid overcrowding food or forcing food down the chute 

Problem :8. Attachments deformed 

Solution :

• Avoid cleaning parts in dishwasher 
• Do not harsh cleaners 

Problem :9. Too much pulp with juicer 

Solution :

• Cut food into smaller parts 
• Insert food slowly 
• Allow all the pulp to eject before adding more food 

Problem :10. Reduce juicer output 

Solution :

• Ensure that the spout is fully opened 
• Ensure that there is no excess pulp in filter basket 
• If yes, stop the juicer and clean filter basket 

Problem :11. Handle lock not closing 

Solution : 

• Push down on the locking tab 
• Open the lock fully 
• Press down and close the lock properly