The Structure And Working Principle Of Microwave Oven; High Voltage Rectifying Circuit - Sanyo EM-U1000W - Compact Microwave,10 Pwr Lvls,800 W,18"x14-3/8"x11-5/8",WE Service Manual
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Also See for EM-U1000W - Compact Microwave,10 Pwr Lvls,800 W,18"x14-3/8"x11-5/8",WE:
- Instruction manual and cooking manual (21 pages) ,
- Instruction manual and cooking manual (21 pages) ,
- Instruction manual and cooking manual (20 pages)
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Pa=KE fErtgδ
Pa Stands for the power the heated matter adsorbed from the microwave field.
K Stands for a constant
E Stands for the microwave frequency.
f Stands for the microwave frequency.
tgδ Stands for loss angle tangent of the heated matter.
Er Stands for relative dielectric constant of the heated matter.
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Microwave oven can be classified to many kinds
according to various construction, volume and control
function. But anyhow, the main electric parts are all
composed of high voltage rectification, cooling system.
Microwave generator, electric control system and
heating chamber (FIG.2-1). Its working process are as
follows: 120V power frequency voltage transferred to
the rectifier through electric control system, and then be
changed to 4000V direct volt-age by the rectifier, and be
then transferred to the microwave generator, the
generator stars working to transfer the microwave
energy to the heating chamber for heating food through
wave guide tube. At the same time, the electric control
system set off the cooling system to cool the working
rectifier and the microwave generator to keep the oven
working steadily from a too high temperature. If
something is wrong with the cooking system because the temperature is too high, the control system would cut
off the power automatically to prevent microwave generator being damaged from the high temperature. Now,
we'd like to introduce the working principle of each part of the widely used model, mechanical control and touch
control microwave oven.
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At present, home use microwave oven adopt this high voltage rectifying circuit as shown at diagram 2-2.The
circuit is a single phase, semi-wave, double voltage rectifying circuit. The circuit has only a high voltage capacitor,
a high voltage diode, a magnetic leakage transformer besides the magnetron, is very simple.
The working principle of the circuit: 120V power boosted through the transformer, output about 2000V alternating
high voltage current when the high voltage winding is at the positive half-circle, the high voltage winding is at the
negative half-circle, the diode is cut off and the magnetron is conducted. The electricity charged at the positive
half-circle of the capacitor is series connected with the positive phase of the winding voltage, and got a doubled,
about 4000V direct high voltage, then transferred to between the cathode and the anode of the magnetron.
120V
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Fig.2-2
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120V
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120V
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Fig.2-3
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