Induction cookers–Everything you need to know about
April 7, 2012 | by techlineinfo.com
Induction cooker- The rising star of modern Kitchens..Before going in details let us discuss about the basic principles of induction cookers
How Induction Cooker works
Induction heating is a completely different method to generate heat as compared with conventional electric heaters such as Coils, Halogen heaters etc. In an induction heater, the cooking vessel itself is a part of heat generating device, or the cooking vessel itself generate heats. In Coils, Hot Plates and Halogen heaters, heat is transferred to cooking vessels through physical contact or proximity. In this case a considerable amount of heat energy is lost.
Induction cookers make use the heating effect of Hysteresis and Eddy current losses of electric machines. These losses are the predominant losses which is termed as “iron losses or core losses” in electric machines like Motors, Generators, Transformers etc. In that case we try to reduce the energy lose due to the iron losses, but here in Induction heating we are generating heat or converting electric energy to heat energy. In other words here we are multiplying the iron losses to generate heat.
Induction heater consists of following parts
- High frequency oscillator.
- Power supply circuits
- Specially designed induction coil to generate electro magnetic field.
- Control and timer circuits.
- Ceramic Cooktop.
Here we are going a little bit technical. Heart of an induction cooker is a high frequency electro magnetic coil, which produce a strong high frequency electro magnetic field. This coil is powered by a high frequency oscillator(20 to 75 KHz). This coil is placed just beneath a shiny ceramic plate (where we place cooking vessels). Whenever a magnetic material (iron, or alloys or iron) is placed over this coil high frequency magnetic filed passes through the pot which generate heat within metal due to Eddy current and Magnetic Hysteresis.
Eddy current is nothing but the current induced in the magnetic material due to the change in magnetic field. This current flows in opposes the main current which generate heat. Eddy current is directly proportional to the frequency . Hence a high frequency current can generate more heat.
Another phenomenon is magnetic hysterics- In simple words it is the resistance of magnetic materials to the rapid change in magnetization. The inertia of magnetic particles in magnetic materials due to the changing magnetic field generate heat within the material. This heat is also directly proportional to the frequency of magnetic field.
Here we can see that the cooking vessel itself is the heat generating element and the whole magnetic field is passing through it. Whenever you remove the vessel from the heater or stops the current flow through the coil, heat generation will be stopped.
Induction heating is a very old technology and it was utilized in industrial and laboratory applications only, but the recent technological development brought this technology to our kitchens.
Advantages of Induction cookers
1. Excellent energy efficiency: Compared to other conventional electric, gas or kerosene stoves induction heaters are highly energy efficient. As discussed earlier, induction cookers generate heat in the cooking vessel itself. Here the energy is directly supplied to cooking vessel without any loss. In all other conventional cooking methods like gas flame , halogen heating or electric coils only few percentage of actual generated heat energy goes to the food. In these cooking methods, energy is first converted to heat then passed to the cooking vessel. Hence a considerable portion of heat is wasted to the surroundings. In gas stove it is 40 to 55% and in electric cookers it is 65 to 70%. Here we can say induction heaters are more than 50% energy efficient than the conventional gas burners. In induction cookers,even the cooking vessel will not be heated up beyond a certain extend. You can remove the cooking vessel from the heater with bare hands.
2. Flexible heating levels and power options: Unlike other electric/gas conventional cookers, induction cookers heat levels can be adjusted instantaneously. In other electric heaters, instant heat variation is not possible. We can only increase or reduce the temperature slowly. Induction cookers give the same flexibility and similar experience of gas burners. Since the heat is proportional to the generated magnetic field, it can be controlled and monitored through digital circuits. Modern induction heaters have pre-set cooking menus like grill, stir, boil, milk, fry etc. You can flexibly set and monitor the power levels. Digital timers help to start/stop the operations.
3. Safety: Conventional Gas burners and coil electric heaters are notorious on safety accepts. Frequent fire and shock hazards due to these cooking systems underlines that. Highly pressurized gas cylinders are more or less equal to a crude bomb. If not handled carefully, even a smallest spark can blow out your whole house. Moreover cooking gas can not be treated as a healthy way of cooking. Combustion of cooking gas generate poisonous gases like carbon monoxide. At the same risk of electric shock always exists in coil or halogen based electric heaters. In terms of safety we can place induction heaters many folds over other cooking systems. Induction heaters don’t heat anything other than the food, you can even place your hand over the cooking plate. Good buy to burnt fingers, Heated kitchens and no more danger to children.
4. Clean and Elegant cook top: See the tidy shiny surface of the cook top. Beautiful and clean cook top give elegant look to your kitchen. Unlike conventional electric heaters, induction heaters wont heat or burn the food spills on the cooktop. It keeps the cooktop cleaner. Moreover it won’t let the frits burn and stick to the cookware bottom.
5. Faster cooking: Normal coil heaters or hot plates take around ten minutes to boil one litter water, while induction heater boils one litter water within three to four minutes. You can set the temperature as per requirement flexibly through the digital interface.
6. Cooler kitchens: In normal gas and electric cooking a considerable amount of heat is dissipated to the surroundings which increase the kitchen temperature. Induction heaters don’t heat anything other than food, hence your kitchen will be much cooler even after hours of cooking. See the image- Only the portion of chocolate bar over the pan melts.
7. Reliability and life: Even though induction heaters can be classified as a high power handling device, it will not be damaged easily as conventional electric heaters.
Disadvantages of Induction Heaters
Cooking Vessels: One of the most predominant disadvantages of Induction heaters- It works only with certain type of cooking pots only. You can use only iron or iron alloy pots in induction cookers. Stainless steel, Cast iron, mild iron pots work well with induction cookers. You can’t use the copper bottom stainless steel pots, Aluminum, Ceramic, Porcelain, Brass, Bronze, Glass Cookware in induction heaters. It is important to note that all stainless steel cookware don’t work well with induction heaters. It greatly depends upon the iron content in the cookware. Just do a simple magnetic test to identify whether a stainless steel cookware is induction heater compatible or not. If a permanent magnet is not attracting or poorly attracting towards the cookware, then it is not suitable for induction cooking.
Shape of the cookware: Base of the cookware must be flat. You can’t use the curved base cookware in induction heaters, hence the typical Indian cookware “Kadai” is not suitable for induction cooking. Pressure cookers are the inevitable cookware of kitchens, but most of the pressure cookers are made of cast Aluminum which is not induction compatible. However nowadays special induction heater compatible pressure cookers are available in market.
Cost: Cost of induction heaters are many times than conventional electric heaters. However it is not fair to compare an induction heater with a normal crude electric coil heater. If you pay for electricity, then throw away your coil heaters /hot plates and go for an induction heater.
Size of Cookware: You will not be able to use very large and too small pots in induction heaters. Normally all modern induction heaters have cookware auto detect feature, means the heater automatically detects the placement of pot to activate the element. It can be considered as a safety measure too. Element will not get energized with the proximity or contact of metallic items such as spoons, tongs or jewelry (bracelets, rings, bangles etc.)
Tips to buy an Induction Cooker
Indian induction cooker market is flooded with Chinese brands. You can get an induction cooker even for Rs 1000/- (~ US$ 20). These cheap Chinese induction cookers are also work good but the reliability of these brands are questionable. Moreover you won’t get after sales support
Size and number of burners: One of the most important decision making factor. Select a cooker as per your size requirement. If you want to place big vassals then go for bigger sized models. For a small family single element induction cooktop is sufficient. In India, multi element induction cooktops are not much popular, hence it’s difficult to find the same in local market.
Features: Some features are common in almost all models – The standard features include
- Heat and power selection
- Pan detection
- Pan size detection and adaptation
- Pre-set menus
- LED/LCD indicators.
- Child lock
However some induction cookers are coming with most advanced and uncommon features like
- Battery backup: Some advanced induction cookers come with an inbuilt rechargeable battery to give backup on power failure.
- Overflow Detection: Smart sensors detects and prevents overflow while cooking. It will keep your kitchen more clean.
- Program mode: Apart from the pre-set cook menus, some induction cooker models offer programmable modes for different recipes.
- Warm mode: Maintains food at the serving temperature with this setting
Accessories: As specified earlier,we can’t use all utensils in induction cooktops. To tap the optimum benefit from an induction cooker, special cooking vessels are required. Some induction heaters come with specially designed cooking accessories such as grills, pots, induction base pans etc.
Cost: Induction cooker is not a costlier or luxurious appliance. In India you will get a branded single element induction cooktop in the range of Rs 3000/- Features of the models available in India are more or less same.
After sales support: Induction cookers are high power devices, high power devices are always prone to damage. Hence good after sales support is important. Go for a brand which gives excellent after sales support at your area. Read the guarantee/warranty terms before purchase.
Popular Induction Cooker brands of India
Bajaj, Prestige, Philips, Morphy Richards, Khaitan, Usha, Jaipan, Crompton Grieves, Pigeon, Sunflame, Preethi, Glen GL, Inalsa, GreenChef, Kenwood etc. are the popular Induction Cooker brands in India. If these brands are not available in your local market, then consider online purchase from the portals like FlipKart, Letsbuy etc.
Demo video of Philips Induction Cooker