Ask an expert in induction cooktops for specific problems

1. There must be electromagnetic leakage when the induction cooker works, and it is just that the business is deceiving people to say that there is no leakage, but the leakage is large or small, and whether it is within the national requirements. For ordinary people, it is not a big problem, because a small amount of electromagnetic damage for a short period of time is reversible, but too long of radiation still has a certain impact on the human body. The principle of injury can be referred to.

2. The type of pot it is suitable for is iron or stainless steel pot bottom, and I also used a stainless steel pot instead of its original pot (because it comes with a leak) has been very good. Personally, I think either you are using a stainless steel double-layer composite bottom pot (not for induction cookers), or the bottom of the pot is uneven and the contact is uneven, or the pot is too big or too heavy. This can be referred to.

According to the maintenance experience, the electromagnetic hail furnace is normal when it is energized, and the alarm will show the fault after starting the heating, because the chip used in each and the spine machine is different, and the meaning of the fault is not the same, but it can be turned on to indicate that the chip processor, the main power circuit, etc. are no problem, so it is recommended to focus on checking that there is no place:

Whether the pot thermistor is in poor contact or damaged, the gated infiltration tube monitors whether the thermistor is damaged;

Whether the power drive circuit is normal, and whether the 8050 and 8550 are detected are normal;

The voltage monitors whether the value of the circuit element changes.

1. Why don't you use direct current for the induction cooker coil? Can DC create eddy currents in metal vessels?

Steady currents cannot produce alternating magnetic fields, and therefore cannot produce eddy currents on metal vessels. One-way vertical pulse current and alternating current can generate alternating magnetic fields, which can generate eddy currents on metal vessels.

2. Is the higher the power supply frequency of the induction cooker coil, the better? What determines the frequency of frequency? What does the frequency affect?

The eddy current effect at high frequencies is significant, but it cannot simply be assumed that "the higher the supply frequency, the better". The "power supply frequency" needs to be selected based on multiple factors. For an induction cooker with a defined power rating, the selected frequency affects the thickness of the solenoid coil.

3. The induction cooker generates a magnetic field through the coil and generates eddy current heating in the metal utensils, so why only the metal utensils on the ** ring produce eddy currents, and why do other metal parts inside the induction cooker not produce eddy currents?

**The magnetic field above or below the circle is strong, and the density of the eddy currents generated in the metal utensils is high. Other metal parts inside the cooker also generate eddy currents, but at a relatively low magnetic field strength, eddy currents are relatively small.

In the alternating magnetic field of paramagnetic metals, a toroidal current perpendicular to the magnetic field lines is generated inside the metal and heat energy is generated. The stove designed and manufactured using this principle for heating pots and pans is called an induction cooker.

Make a coil with alternating current, and put iron or special alloy metal container on it, which can play a role in the heating effect of the induction cooker.

The early low-frequency induction cooker directly used the alternating current with a frequency of 50Hz in the power grid to generate a low-frequency alternating magnetic field through the induction coil for direct induction heating. But because of the low utilization rate of this kind of low-frequency induction cooker, the volume is bulky, and the noise is also large, it has been eliminated, and now we use a high-frequency induction cooker, and the circuit has become complicated, but the high-frequency induction cooker is small and the heating efficiency is very high. Imitation medium.

It can be that the heater is broken, for the sake of safety, it is best to find a professional maintenance point for repair, you can first **consult**, if it is too expensive, replace it with a new one.

The pot alarm is not heated. If you can fix it yourself. Disassemble the machine to check whether the power supply voltage of 305V, 18V, 5V is normal, and whether the rectifier bridge and capacitor are in good condition.

and whether the drive transistors S8050 and S8550 are intact. Control whether the voltage of each arm of LM339 is normal. No, look for the after-sales service department in the manual of the induction cooker.

From the data you provided, there are two reasons why the output voltage of the 7805 is abnormal

1. At this time, touching 7805 should be hot, indicating that the load circuit after 7805 has serious leakage or short circuit, and the components in the 5V power supply circuit should be detected first;

2. If the 7805 is not overheated when touched, it is caused by the change of the value of the components in the power supply circuit between 7805 and 18VDC or poor contact, which is often caused by the change of the current limiting resistance in series in the 18VDC circuit.

*Under normal circumstances, the 1 pin (input) of the 7805 should have 8-12V as normal, because you only measure 6V, which can basically negate the problem caused by the large internal resistance of the 7805.

Maybe there's a short circuit behind the 7805.

If the induction cooker is broken and you can't find the problem, don't worry, it's easy to solve the problem by teaching you to practice blindly.

There is a strong radiation hazard, and attention should be paid to ventilation when using.

Check the 7805 voltage input circuit.

The correct answer is that it will be heated, simply put, the principle of the induction cooker is to use the eddy current phenomenon of high-frequency electromagnetic field, as long as the metal that can be adsorbed by the magnet is placed on the induction cooker, it can be heated by the induction cooker. Studying deeply, this method is similar to the heating principle of microwave ovens, their medium is different, one is water molecules as the medium. One is to use iron metal as a medium.

The induction cooker is designed with multiple electronic protections, and when the empty pot is heated to a certain extent, the protection is turned on, and the heating of the pot will stop. When you take the pot off, the cooker will also stop working. It's all a credit to the protection circuit.

The principle of an induction cooker.

Induction cooker is the use of magnetic field induction eddy current principle, it uses high-frequency current through the toroidal coil, thereby generating countless closed magnetic field force, when the magnetic field lines through the bottom of the magnetic conduction (such as: iron pot), both will produce countless small eddy current (a kind of alternating current, household induction cooker uses 15 30kHz high-frequency current), so that the pot body itself high-speed heating, and then heat the food in the pot.

We can understand the heating principle of induction cooker so simply:

The inner coil of the pot and the induction cooker form a high-frequency transformer, the internal coil is the primary transformer, and the secondary is the pot. When the internal primary coil has an alternating voltage output, it will inevitably generate an induced current on the secondary pot, and the induced current will heat up through the resistance of the pot itself (so the pot itself is also a load) and generate heat. Suppose:

When the internal primary heating plate has alternating voltage output, if the secondary and load (pot) are not present, the output power will be very low. Of course, in the actual circuit, we must quickly detect this change in power and turn off the alternating current output to the coil disk.

Because non-permeable materials cannot effectively gather magnetic field lines, they can hardly form eddy currents (just like an ordinary transformer can not effectively transmit energy without a silicon steel core, and only two windings cannot effectively transmit energy); In addition, magnetic materials with particularly poor electrical conductivity have too high resistivity and generate very little eddy current current, and they cannot generate heat well. Therefore, the pot material used in the induction cooker is a metal or alloy with relatively good conductivity, ferromagnetic material and their compounds.

The pots generally used are: cast iron pots, pig iron pots, and stainless iron pots. Pure stainless iron pot material does not work well on induction cooker due to its very low magnetic conductivity.

from the Internet).

Of course not. Induction cooktops heat molecules. Iron can shield electromagnetic waves, and there is an introduction in high school physics books.

The working principle of the induction cooker is the principle of electromagnetic eddy current, the bottom of the plate of the induction cooker is a coil wound by insulated wire, and the following is the control circuit board, when working, the coil is induced with the pot made of iron metal or other magnetizable metals outside, so that the bottom of the pot produces electromagnetic eddy current to heat the pot and heat the food.

The bottom of the induction cooker is uneven, and the contact area with the induction cooker is only seventy or eighty percent, which will affect the heat absorption a little, but the efficiency of the heat transfer of the induction cooker is determined by the following electromagnetic coil and control circuit, so the efficiency of the heat transfer of the induction cooker has not changed. The heat loss is there, but it is not large, because the electromagnetic eddy current in the center is relatively strong and the sides are weaker. So the losses are not big.

I really don't feel very good, so I just went to buy one, it's not expensive, just feel at ease.

The uneven bottom of the pot will lead to inaccurate temperature sensing of the induction cooker, which may protect the temperature in advance. In addition, the bottom of the pot is uneven, and the magnetic field will be partially lost.

It's normal, feel free to use!