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Induction hob

Belongs to:

Kitchenware and household appliances

Synonyms:

Induction stove

Description:

The heating process of an induction hob is based on inductively generated eddy currents. For that purpose, coils are placed beneath the ceramics cooking field to generate an alternating magnetic field. This alternating field induces eddy currents in the metallic cooking pot placed on top of the cooking field which is thereby heated due to its ohmic resistance. Only special cooking pots that are explicitly marked as suitable for inudction cooking can be used. Typcially, these pots are made of ferromagnetic material, such as iron, cobalt or nickel, which forces the alternating magnetic field into the outer regions of the saucepan's floor. This phenomenon known as Skin effect increases the ohmic resistance of the cooking pot and thereby enhances the cooking process. Hysteresis effects caused by the change in magnetization due to the alternating magnetic field equally contribute to the heating process. As part of alternating magnetic field cannot be picked up by the cooking pot, the position of the cooking pot on the cooking plate is decisive for both the cooking process and the exposure of the cook. For minimal cooking time and minimal exposure to magnetic fields, the pot has to be placed exactly on the designated area. Contrary to that, for a coffee pot which never fills out a cooking plate due to its lesser diameter, the optimum position for minimal exposure is generally off center.

Unless otherwise stated, the operating frequency confirms with measured frequency, i.e. the measurement was performed at the operating frequency of the induction stoves.

Frequency ranges:

• 20–100 kHz
• 105 kHz

Type of field:

electric and magnetic

Measurements (acc. to literature)

References

1. Kos B et al. (2011): Pre- and post-natal exposure of children to EMF generated by domestic induction cookers
2. Mantiply ED et al. (1997): Summary of measured radiofrequency electric and magnetic fields (10 kHz to 30 GHz) in the general and work environment
3. Swerdlow AJ et al. (2012): Health Effects from Radiofrequency Electromagnetic Fields - RCE 20
4. Leitgeb N et al. (2008): Electric emissions from electrical appliances
5. Christ A et al. (2012): Exposure of the human body to professional and domestic induction cooktops compared to the basic restrictions
6. Guldimann R et al. (2011): [Magnetic field exposure from professional induction hotplates - Health protection for occupational exposure. Measurements at workplaces in the gastronomy in the year 2009/2010]
7. Rickli H et al. (2003): Induction ovens and electromagnetic interference: what is the risk for patients with implanted pacemakers?
8. Bullo M et al. (2013): Analysis of Stray EM Fields Generated by Induction Cooktops
9. Binggeli C et al. (2005): Induction ovens and electromagnetic interference: what is the risk for patients with implantable cardioverter defibrillators?
10. Viellard C et al. (2007): B-Field Exposure From Induction Cooking Appliances. ITIS-Foundation
11. Leitgeb N et al. (2008): Magnetic emissions of electric appliances
12. Leitgeb N et al. (2008): Magnetic emission ranking of electrical appliances. A comprehensive market survey
13. Tenforde TS (1992): Biological interactions and potential health effects of extremely-low-frequency magnetic fields from power lines and other common sources