defrosting timer is an important component of the control circuit of frost-free refrigerator. It can control the time interval of frost, control the operation of the defrosting heater regularly, Defrost Timer Relay and defrost the refrigerator automatically. defrosting Timer timing motor and compressor operation, when the compressor cumulative work hours (usually about 8h). The evaporator will have a layer of frost. At this time, the defrosting timer switch will automatically convert to the defrosting circuit, while cutting off the defrosting timer motor and compressor power supply, Defrost Timer Relay and then the evaporator and other components of the cream. After the defrosting is finished, defrost timer switch is automatically converted to the refrigeration circuit, the compressor restarts, defrost timer again.
The defrosting timer is composed of micro motor, gear box, cam, Defrost Timer Relay movable contact and static contact, and is equipped with 4 terminals and a hand-controlled knob.
The defrosting timer consists of miniature motor, gear turning box and contact cam mechanism. It can be divided into mechanical defrost timer and electronic defrost timer. The following figure shows the defrost timer structure.
1 Mechanical defrosting timer by the timing motor and a group of contacts, Defrost Timer Relay the contact action time is equal to the cumulative operation of the compressor time, the interval according to different models and different, usually 8h action once, the defrosting time of about 10min. The frost layer dissolves, the bimetallic switch jumps off, and the defrosting ends. Because at this time defrost timer switch is still in the position of 1-3, Defrost Timer Relay the timer motor can also rotate normally. 2min, switch from 3 to 2, connected to the compressor and fan, refrigerator start refrigeration cycle, defrosting timer into the next round of frost timing.
2 The electronic defrosting timer is controlled by the microcomputer to control the whole frost process. Defrost Timer Relay It is characterized by the use of electronic counters to replace mechanical timing motors.