KitchenAid Kitchen Aid KICU500X Technical Education page 16

Figure 2
Remember,
opposites attract and by providing voltage,
the positive and negative charges in the
induction coil create a tremendous magnetic
field.
The electrical circuit from our house supply
is 240 VAC and 60 Hz. Meaning the positive
and negative electrons, of a sine wave, shift
back and forth 60 times a second. Now how
do we make this movement happen quicker?
We use a frequency converter to step up
the 60 Hz frequency from our home power
supply to between 20 and 60 THOUSAND
Hz . Meaning now the positive and negative
electrons in the coil alternate back and forth
The range of the frequency converter is 20 to 60 kHz.
Induction cooking reacts better with a lower frequency,
so 20 kHz produces the most energy.
60 KHz is not as efficient an operation as 20 KHz, so as the frequency rises the efficiency of
the induction operation decreases.
20 THOUSAND times per second. What do
you think the electrons in the pan are doing?
(creating heat very quickly).
Induction cooking and the movement created
in the cookware performs better at the lower
frequency of 20KHz. Changing the
frequency upwards to 60KHz reduces the
efficiency of induction operation. This is
how we regulate the performance between a
Aligned positive and
negative charge
high, medium and low setting at the
cooktop. By speeding up the alternating
current in the induction coil, the electrons in
the pan will move very quickly and provide
instant heat to cook food. This magnetic
field that we produced works in the 2-3cm of
the bottom of the cookware, creating heat in
just the bottom of the cookware. You always
see the dollar bill trick where they put a
dollar bill between the cooktop glass and the
pan being heated, well now you know how it
works. The paper money does not contain
the electrons (like in metal) to stimulate and
will not provide any heat. Same thing with
the glass cooktop, the glass doesn't get hot
(except from the heat provided from the hot
cookware) because it doesn't contain the
material makeup that the metals do to
stimulate movement and friction in the glass.
3-2