2.2
GENERATER.
Microwave generator is the
of microwave oven. The quality of a microwave oven mostly depends on the
quality of the microwave generator. A microwave generator is mainly composed of magnetron and its power
supply
is the typical
diagram of the present used microwave
generator. The power
supply circuit is composed of rectifying circuit and filament circuit.
Usually, we adopt continuous wave magnetron. can turn the direct energy which is applied to the magnetron
being high voltage rectified to microwave energy, the power supply circuit supply a direct
voltage
the cathode and anodę of the magnetron, a filament voltage to the cathode filament of the magnetron.
The working process of the magnetron: When the anodę volt-age gradually rises
zero, the anodę current is
the power is
smali as
When the anodę voltage rises to
voltage value, the
magnetron
oscillating, and the anodę current
increase
provided the anodę voltage rises a
little
the anodę current would increase a
and would reach the
value
the anodę voltage is
it would cause the anodę
current swing fiercely, even
the magnetron stop oscillating.
For keeping a steady output, the power supply circuit of the
oven
supply a stead direct current voltage. The filament
voltage of the magnetron must be supplied by an alternating
current voltage. For
the circuit, it would be supplied
by the same leakage magnetic transformer with the anodę
power (high voltage power). The filament of the magnetron
which the present used microwave ovens
treated through
some
and all
the
start
But when in cold start, there
is a very strong surge electric
to the surface of the anodę, and would be harmful
to the anodę. In order to reduce the surge voltage, the filament
of the magnetron must be connected as the FIG.2-3 shown. In
this figurę, when the anodę current of the magnetron circulates,
the filament current should
to the FA end from the
end.
2.3
SYSTEM
100 200 300 400
anodę current
Fig. 2-4
In the working process of the microwave oven, the magnetron
makes the anodę temperaturę rise due to
anodę
caused by the electronics strike the oven surface and the heat radiate of the cathode. To prevent the anodę
temperaturę rise too high, thus
the working steady and its
span, it is
to
the magnetron.
According to the
models and
output of the magnetron, compelling wind cooling and flowing
can be adopted. Usually, the
used microwave oven adopts the compelling wind cooling
and all
fixed with cooling
Cooling system includes fan
air
air entrance, air vent etc. The flowing direction of the cooling wind
should. Be parallel to the cooling fin of the magnetron.
we adopt the method of air
rather than air
absorb. And all the cabinet of the oven is with air entrance and air vent, the hot wind blowing through the
magnetron is guided with air
to improve the cooling
In the technical parameter chart of the magnetron,
it usually will give out the requirement of cooling wind. A
of cooling wind would damage the character of
the magnetron, even burn out the magnetron. The amount that the fan blasted should not be less than the
requirement. When fix the fan,
must be paid to prevent the cool wind from blowing directly to the
of the magnetron to avoid blasting.
2.4
SYSTEM.
To those mechanical control microwave
electric control system mainly composes of interlock switch, timer,
power distributor and thermal cutout, etc. The electric control system of those tough control microwave oven is
mainly composed of interlock switch, computer controller and thermal cutout, etc.
