strong power part and weak power part, and electric transformer is the cut-off point.
Strong power part before transformer while weak power part after transformer.
For strong power part, the phase line enters through 30A compressor relay RY1, then
passes fuse, fan motor, four-way valve, water motor. Fan motor is made up of tap motor
and centrifugal fan. There are high fan speed and low fan speed, and be controlled by two
5A relay (RY3 and RY4) respectively. RY3 for high speed while RY4 for low speed.
Water motor is shaded-pole motor and is controlled by relay RY2. Four-way valve is
controlled by RY5.
For weak power part, it can be divided into two parts: power supply part and control
part. The part of power supply goes out through transformer output-port, then passes four
bridge rectifiers of commutation diode, capacitive E1 wave filtering , and get volts d.c.
about 12V , to supply relay and drive integrated package ULN2003, the other way go
through current-limiting resistance RR1 and 5V stabilized voltage 7805 to supply SCM ,
peripheral circuit and display power. The core of control part is HT46R47. Its input
parts are keys, receiving head, room temperature sensor , evaporator temperature sensor
and water-level detecting circuit; its output parts are control relay, buzzer and status
display.
Keys, LED or LCD are man-machine conversation windows. By keys we can change
machine work status; LED or LCD displays machine current work status. Remote control
receiver: when controlled by remote control, the remote control receiver gets the control
signals from remote control, then sends them to SCM. Evaporator temperature sensor
sends the surface temperature of evaporator to SCM. Water-level detecting circuit detects
if water tank is full, and sends the signals to SCM. Analyzed by SCM process, control
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