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الأجهزة القابلة للارتداء

Raymond M. Tucker · Public domain (expired patent)

أنشأه

22. سبتمبر 2026

Induction Hob

The induction coil already published makes a changing magnetic field, and the induction motor uses one to drive currents in a rotor. The cooking rung uses the same trick to heat the pan itself: no element, no flame, and a cold top - the pan is the only thing that gets hot. **US 4,169,222**, "Induction cook-top system and control", Raymond M. Tucker, assigned to Rangaire, filed 26. July 1977, granted 25. September 1979: mains rectified to DC, switched into induction heating coils under a non-metallic top, with the power set by the switching. **A mains hob is never opened or built here.** You build a LOW-VOLTAGE induction heater from a 12–24 V module and measure which metals it can heat - which is exactly why some pans work on a hob and others do nothing.

متوسط

3 hours

التعليمات

Wind a work coil

Wind 6 turns of 10 AWG bare copper wire round a 60 mm former into a flat spiral, leaving 80 mm tails. Keep the turns evenly spaced and not touching.

المواد لهذه الخطوة:

سلك نحاس عارٍ 10 AWG1 متر

الأدوات المطلوبة:

طقم زرّاديات

مسطرة فولاذية

Power it safely

Bolt the coil to the ZVS module's terminals. Set the bench supply to 12 V with a 5 A limit; the module draws several amps and its transistors get hot. Never run it with no metal near the coil for more than a few seconds, and keep the supply under 24 V.

المواد لهذه الخطوة:

ZVS Induction Heater Module1 قطعة

الأدوات المطلوبة:

مصدر تغذية مختبري قابل للضبط

نظارة أمان شفافة

Cut six discs

Cut 40 mm discs from mild steel, stainless (both a magnetic and a non-magnetic grade if you have them), aluminium and copper, all the same thickness. Deburr the edges. Try a magnet on each and note which hold it.

المواد لهذه الخطوة:

لوح فولاذ طري1 قطعة

لوح من فولاذ مقاوم للصدأ1 قطعة

صفيحة ألمنيوم1 قطعة

صفيحة نحاس1 قطعة

طقم مغناطيسات نيوديميوم1 طقم

الأدوات المطلوبة:

مقصّ صفائح

مبرد معادن

Sixty seconds each

Rest each disc on a ceramic tile 5 mm above the coil, note its starting temperature, run for 60 seconds at the same supply setting, and read it again. Lift hot discs with pliers and gloves; let the module cool between runs.

الأدوات المطلوبة:

ميزان حرارة بالأشعة تحت الحمراء

ساعة إيقاف

قفازات لحام

طقم زرّاديات

The same test on a real hob

If a commercial induction hob is to hand, put a cast-iron skillet on it, then an aluminium saucepan, and see which one it will even acknowledge. Then hold a magnet to each base.

الأدوات المطلوبة:

مقلاة حديد زهر

قِدر عميق الجوانب

طقم مغناطيسات نيوديميوم

Skin depth and your results

جارٍ تحميل دفتر Jupyter…

History & Context

**What the patent specifies:** a cook-top with rectifier, gated semiconductor switches and induction heating coils beneath a non-metallic top, with the heat set by how the coils are switched. **Modern build (derived):** a low-voltage ZVS heater and metal discs. Induction reached kitchens slowly because the electronics were dear; efficiency into the pan is high and the top stays cool enough not to burn spills on. Its limits: the pan must be magnetic (so much old aluminium and copper cookware is useless), the electronics whine, and a pan smaller than the coil couples poorly.