What is a Refrigerator Defrost Timer? Structure, function and principle of operation

Refrigerator defrost timer is a device that helps control the heating, cooling, and defrosting process of the refrigerator so that the refrigerator always works stably. Let’s find out what the refrigerator defrost timer is, as well as its structure, function and operating principle through the following article!

What is a Refrigerator Defrost Timer?

Refrigerator defrost timer is a device that controls the heating, cooling and defrosting process of the refrigerator, ensuring that the refrigerator always keeps the right temperature, stable operation, and does not cause the indoor unit to close. snow.

Structure and working principle of refrigerator defrost timer

Structure

Timer is composed of:

• 1 single-phase AC motor M: Acts as a compressor motor.
• Engine shaft.
• Gear reduce transmission speed.
• 1 cam wheel has a speed of 1 revolution / 24h.

Working principle

• When you supply power to the refrigerator, the timer contacts 1 – 4 will close, instead the motor M will rotate to defrost time.
• Next, the camshaft will act so that contacts 1 – 4 of the timer open and close contacts 1 – 2 .
• When current passes through relay -7 , fuse 70 and through the resistor wire, the resistor wire will heat up the evaporator to trigger defrost.
• However, when the evaporator temperature is greater than – 7 degrees Celsius , relay -7 will open the contact to stop supplying power to the defrost resistor.
• At this time, the timer with resistor will continue to rotate, 15 minutes later, contacts 1 – 2 of the timer will open and close contacts 1 – 4 to supply power to the refrigerator compressor to continue performing the process. chilled.

Location of refrigerator defrost timer

Refrigerator defrost timer can be located in the vegetable compartment or on the back of the refrigerator in the electrical box next to the compressor depending on the refrigerator model.

Function of the refrigerator defrost timer

The refrigerator defrost timer has the function of disconnecting the power supply to the compressor instead of supplying power to the defrost resistor to melt the ice on the indoor unit.

How to check if the refrigerator defrost timer is still good or not?

To check if the defrost timer is still good, do the following:

• Use a scale meter to measure the resistance and measure between the coil legs ( pins 1 and 3 ). Then you rotate the timer shaft until there is a ” beep ” sound and continue to measure the resistance at the contact that powers the defrost system ( resistance between pins 3 and 2 ).
• When the resistance is about a few Ohm, turn the shaft slightly until the second ” beep ” appears and measure the resistance between pins 3 and 4 – which is the power supply contact for the compressor.

The above article has provided you with information about what is a refrigerator defrost timer as well as its structure, function and operating principle for you to better understand this device. If you have any questions, leave us a comment below for answers!