Defrost Timer Structure
Defrost timer is an important component of frostless refrigerator control circuit. It can control the defrosting time interval, timing control defrost electric heater work, Defrost Timer Relay automatic defrost for the refrigerator. Defrost timer The motor runs at the same time as the compressor, and when the compressor has been working for several hours (usually about 8 hours). There will be a layer of frost on the evaporator. At this point, defrost timer switch will automatically switch to the defrost circuit, Defrost Timer Relay while cutting off the defrost timer motor and compressor power, and then evaporator and other components to defrost. After the defrost is completed, the defrost timer switch is automatically switched to the cooling circuit, the compressor is restarted, and the defrost timer is restarted.
The defrost timer consists of a miniature motor, a gearbox, and a contact cam mechanism. It can be divided into mechanical defrost timer and electronic defrost timer.
Defrost timer structure.
1) mechanical defrost timer by the timing motor and a group of contacts, the contact action time is equal to the cumulative operation of the compressor and the time interval, depending on the type of action vary, usually 8h action once Frost time is about 10min. Frost layer melting, bimetal switch jump, defrost end. Since the defrost timer switch is still in the 1-3 position, Defrost Timer Relay the timer motor can also rotate normally. 2min, the switch from 3 to 2, connected to the compressor and fan, the refrigerator began to cool the cycle, defrost timer into the next round of defrost timing.
2) electronic defrost timer is through the microcomputer to control the entire defrost process. It is characterized by the use of electronic counter to replace the mechanical timing motor.
Fully automatic cream refers to the refrigerator in the defrost process, do not need to operate any button or switch, you can automatically complete a series of defrost operations. Full automatic defrost device generally has three forms: the basic automatic defrost device, the cumulative type of automatic defrost device, Defrost Timer Relay automatic defrost device. The timer used in the fully automatic defrosting device is called a defrost timer, which consists of a micro motor, a gearbox, a cam, a movable contact and a stationary contact. The external terminal is equipped with four terminals and one hand Knob.
Road defrost timer contact action time set in every 8h (according to the manufacturer design, time) action once.
After the compressor is running for 8 hours, the defrost timer disconnects the circuit to the compressor, turns on the bimetallic defrosting thermostat and defrost heater circuit, Defrost Timer Relay and begins to heat and defrost the evaporator. Defrost timer control defrost time is generally 15 ~ 30min.
After the frosting of the evaporator surface melts, the temperature inside the tank rises to 10 to 16 ° C, the bimetallic defrosting thermostat turns off the defrost contact, Defrost Timer Relay and the defrost heater stops heating, and the defrost timer starts at the next Cycle timing.