There
are two techniques of glass-ceramic heating:
* The infrared.
* The induction.
These glass-ceramic hobs are as like as two peas.
The difference is only obvious once hobs are turned on.
The infrared one glows red while the induction doesn’t seem to operate.
The first is provided with radiant or halogen sources that transmit heat by radiation and conduction.
The second feeds a magnetic source, an inductor, which is placed under the glass-ceramic surface and transforms the magnetic energy into heat.
The traditional electrical hotplate is based on thermal conduction, while induction is based on the principle of the electromagnetic field.
The principle of heating by induction is a natural phenomenon discovered in the 19th century by several physicists, among whom Léon Foucault. He highlighted the development of currents facing the magnetic field in a moving metallic mass or a fixed metallic mass run through by a variable magnetic flux. These eddy currents in comparison to short-circuits cause a heating effect (Joule effect) in the mass.
* The infrared.
* The induction.
These glass-ceramic hobs are as like as two peas.
The difference is only obvious once hobs are turned on.
The infrared one glows red while the induction doesn’t seem to operate.
The first is provided with radiant or halogen sources that transmit heat by radiation and conduction.
The second feeds a magnetic source, an inductor, which is placed under the glass-ceramic surface and transforms the magnetic energy into heat.
The traditional electrical hotplate is based on thermal conduction, while induction is based on the principle of the electromagnetic field.
The principle of heating by induction is a natural phenomenon discovered in the 19th century by several physicists, among whom Léon Foucault. He highlighted the development of currents facing the magnetic field in a moving metallic mass or a fixed metallic mass run through by a variable magnetic flux. These eddy currents in comparison to short-circuits cause a heating effect (Joule effect) in the mass.
Only
since the middle of the 20th century induction started being used as a heating
means, mainly in industries like the steel (induction furnaces). Induction only
found its place in kitchens in the 80s, or even 90s for domestic electrical
appliances with the marketing of the hob named IX1. The IX2 generation followed
in 1992, IX3 (1996), IX3WR (2000) and currently IX4000 (2002) and IX6 (2005)
generations.
The operating principle is innovating. Contrary to other cooking modes, it is the container itself, which heats and not the hob.
You put a saucepan down and this is sufficient to initiate the heat while the hob remains cold. The heating element is nothing but the container metal, which transforms the magnetic energy into thermal energy. Induction qualities are flexibility, low inertia, easy cleaning, good efficiency and thermal safety. Induction enables a litre of water to boil in two minutes, milk to heat without overflowing and chocolate to melt just as desired. Induction efficiency may reach up to 90% according to the types of cooking.
With such a technique, only the container heats. Inertia is therefore low and, above all, the plate temperature never exceeds the saucepan temperature. Stepping from the mildest temperature to the strongest power, in an instant and while diffusing heat in a homogeneous way.
This technology is incomparable to those of present due to the induction method.
The operating principle is innovating. Contrary to other cooking modes, it is the container itself, which heats and not the hob.
You put a saucepan down and this is sufficient to initiate the heat while the hob remains cold. The heating element is nothing but the container metal, which transforms the magnetic energy into thermal energy. Induction qualities are flexibility, low inertia, easy cleaning, good efficiency and thermal safety. Induction enables a litre of water to boil in two minutes, milk to heat without overflowing and chocolate to melt just as desired. Induction efficiency may reach up to 90% according to the types of cooking.
With such a technique, only the container heats. Inertia is therefore low and, above all, the plate temperature never exceeds the saucepan temperature. Stepping from the mildest temperature to the strongest power, in an instant and while diffusing heat in a homogeneous way.
This technology is incomparable to those of present due to the induction method.
Operating principle
An
induction hob operates due to the electromagnetic properties of most containers
used on traditional hobs. One can
compare this hob with a transformer of which the secondary winding would have
been shorted. A significant internal current arises therein and causes quick
heating.
The
saucepan can be compared with a shorted set of concentric whose internal
resistance is not zero. From the
function keys, you control the electrical power supply to the transformer
primary winding which generates a magnetic field. This field induces currents
at the bottom of the container placed on the hob. These induced currents heat
the container immediately, which transmits the produced heat to the food
inside. Cooking is performed efficiently with almost no loss of energy. The
appliance heating power is pushed to its maximum.
Skin effect
An induced current in a metallic mass will only cause significant heating if it
flows through a significant resistor (P=RI2). A ferrite saucepan has only low
resistivity. This is where a second natural phenomenon occurs, which is called
‘Skin effect’.
The
propagation of the high-frequency current is not performed in the same way as a
direct current. Contrary to direct
current, where current flows with consistency in a conductor, in HF its density
varies and decreases exponentially as you move away from the conductor surface.
The
current flows predominantly in wire periphery. The decrease in the effective
cross-sectional area of the conductor causes an increase in its resistance.
At
a 20KHz frequency, and for a steel saucepan (magnetic ferritic material), the
thickness of the saucepan in which the induced currents flow is approximately
35 µm. This allows generating a current in only a part of the saucepan bottom.
The resistance becomes significant and the heating consequent therein.
For
a non-ferritic material, such as aluminium, the thickness is approximately 590
µm, the saucepan behaves then as a quasi-zero resistor (short-circuit), which
is prejudicial to electronics. The board will take this discrepancy into
account and will display the phenomenon by making the control panel flash.
Therefore, this type of material is not adapted.
The
efficiency is the ratio that exists between consumed energy (gas or
electricity) and energy converted into heat. Large differences exist between
induction, range-top appliance, and other cooking modes. These efficiencies may
vary depending on the diameter and quality of the container used.
Removing
the container from a source is sufficient to stop the cooking immediately,
there is no energy waste. As long as there is no container on a source, the
source does not heat, the power indicator lights are flashing. This hob
consumes thus much less energy than hobs fitted with traditional gas or
electricity hobs.
Electrical connection
Hobs
with three or more sources have five wires to be connected. Wires other than
the yellow/green shall be connected in pairs to a 32 Amp connector (connector
specific for cooking).
Hobs loosely fitted, with connecting block or combined with gas can be connected to a 16 A connector (Conventional connector).
Hobs loosely fitted, with connecting block or combined with gas can be connected to a 16 A connector (Conventional connector).
If
the user has three-phase power supply, the connection can be distributed over
two phases by separating the black wires of the 5-way cord. The advantage is to work only with a 16A
protection.
On
hob power-up or after prolonged power cut, a luminous code is displayed on the
keyboard. It disappears automatically after 30 seconds, or from the first
action on any one key on the keyboard.
Temperature limiter
Each inducer uses a NTC sensor measuring the container temperature through the glass. This system help protecting the hob and the containers against over heating (Pan without food for example). In case of overheating, the temperature of the pan is regulated around 300°C. This temperature does not allows the deterioration of the PFTE (anti sticking material used in the pans).Damages start above 340/350°C.
Each inducer uses a NTC sensor measuring the container temperature through the glass. This system help protecting the hob and the containers against over heating (Pan without food for example). In case of overheating, the temperature of the pan is regulated around 300°C. This temperature does not allows the deterioration of the PFTE (anti sticking material used in the pans).Damages start above 340/350°C.
Glass
ceramic is a silicium-based material that does not expand like glass. Its
dimensions do not practically vary up to 750°C, as a part of the molecules
composing it expands under heat, while an equal number retracts. A feature of
this material is that it is a poor heat conductor and therefore limits heat
loss.
The
plane surface of the glass ceramic and the sensitive controls make cleaning
easy. The own cleaning difficulties of radiant and halogen sources are usually
groundless on induction hob, owing to the low temperatures attained by the
table. However, a saucepan with humid bottom put on the source leaves limestone
traces. Sugar discharges should be cleaned immediately, as in contact with hot
glass ceramic the sugar caramelizes. When cooling down, it retracts and attacks
the coating. Lastly, the glass-ceramic hob is not a working plane and thus is
easily scratched.
Power supply
To
supply the inducers, it is necessary to apply a high frequency. To change over
from 50Hz to 50KHz it is first necessary to rectify the main voltage through a
diode bridge. A filtering capacitor (of 5µF generally) is associated in order
to attenuate the high-frequency signals. As shown by the illustration, the
rectifier output voltage is approximately the main peak voltage (i.e. 310 VDC
approx.) when no inducers are supplied. This voltage drops during the
operation.
The
inverter is used to transform a DC signal into an AC signal with adjustable
frequency. The inverter consists of two transistors (whose technology can vary
according to the hob generation), two capacitors and two recovery diodes
(indispensable on any inductive circuit).
Transistors are frequency controlled by a generator. This frequency
varies between 25KHz (for 2800W) and (50KHz for 500W).
Control
The
entire operation is managed by a microprocessor.
* On generation IX1, a specific board performed the control; the power was managed by another board.
* On generation IX2, these two boards have been soldered and have become indissociable.
* On generations IX3, IX3WR and IX4000, power and control are entirely associated. So, the board integrates: A 5 and 12 VDC clipping power supply (which is also the keyboard power supply), the control part (in liaison with the control keyboard), the rectifier part, the inverter part, and lastly, for board IX4000 and IX6, the filtering part.
* On generation IX1, a specific board performed the control; the power was managed by another board.
* On generation IX2, these two boards have been soldered and have become indissociable.
* On generations IX3, IX3WR and IX4000, power and control are entirely associated. So, the board integrates: A 5 and 12 VDC clipping power supply (which is also the keyboard power supply), the control part (in liaison with the control keyboard), the rectifier part, the inverter part, and lastly, for board IX4000 and IX6, the filtering part.
The error codes
'Error' codes are a precious aid to diagnostic. Take care to well identify the model to be troubleshooted, as codes do not always have the same meaning.
'Error' codes are a precious aid to diagnostic. Take care to well identify the model to be troubleshooted, as codes do not always have the same meaning.
The test keyboards
During a diagnostic, it is necessary to know whether it is the control keyboard or the power board, which is defective. However, you must not omit the filter board, which includes two fuse pads and the power supply relay. Generations IX3 on the one hand and IX3WR, IX4000, IX6 on the other hand do not use the same encoding process. It is therefore advisable to be provided with two different test keyboards.
* IX3 keyboard: 79X5460
* IX3WR, IX4000 and IX6 keyboards: 79X9920
This keyboard will enable all the keyboard of each range to be replaced. In event of degradation with use, base plates can be replaced:
* 6-point base plate (IX3) : 79X5461
* 8-point base plate (IX3WR, IX4000, IX6) : 79x9921
During a diagnostic, it is necessary to know whether it is the control keyboard or the power board, which is defective. However, you must not omit the filter board, which includes two fuse pads and the power supply relay. Generations IX3 on the one hand and IX3WR, IX4000, IX6 on the other hand do not use the same encoding process. It is therefore advisable to be provided with two different test keyboards.
* IX3 keyboard: 79X5460
* IX3WR, IX4000 and IX6 keyboards: 79X9920
This keyboard will enable all the keyboard of each range to be replaced. In event of degradation with use, base plates can be replaced:
* 6-point base plate (IX3) : 79X5461
* 8-point base plate (IX3WR, IX4000, IX6) : 79x9921
In
event of problem with power supply, it is advised to check:
* Whether 'fuse' pads are out of order
* Whether the power relay is controlled (12VDC)
* Whether the relay delivers 230VAC to the board.
* Whether the relay delivers 230VAC to the fan.
* Whether 'fuse' pads are out of order
* Whether the power relay is controlled (12VDC)
* Whether the relay delivers 230VAC to the board.
* Whether the relay delivers 230VAC to the fan.
Measurements on IX3 power board
These test points are used to check whether the independent filter board
* delivers a voltage for the control supply
* delivers a voltage for the power supply
* power relay is controlled by the command.
These test points are used to check whether the independent filter board
* delivers a voltage for the control supply
* delivers a voltage for the power supply
* power relay is controlled by the command.
Measurements and checks on IX3 WR power board
These test points are used to check whether the independent filter board
* delivers a voltage for the control supply
* delivers a voltage for the power supply
* power relay is controlled by the command.
These test points are used to check whether the independent filter board
* delivers a voltage for the control supply
* delivers a voltage for the power supply
* power relay is controlled by the command.
