Design and production of a high performance compressor voltage stabilizer delay device

During maintenance, I have come across many types of compressor voltage stabilizers. Although their circuits are different, they all have certain defects, unstable performance, and high failure rate. After repeated research, the following circuit was designed and made into a finished product. After two years of use, the performance of this machine is stable and it is very suitable for use in rural areas with unstable voltage, so that the compressors of refrigerators and air conditioners can be more thoroughly protected.

Circuit principle: The circuit is shown in the figure below. When the mains voltage is normal (185V-245V), IC1, IC2, IC3, and IC4 all output low level, and relays J1 and J2 do not operate. When the mains voltage is greater than 245V but less than 270V, IC1 outputs high level, and IC2, IC3, and IC4 all output low level. At this time, J1 operates, its normally closed contact is disconnected, and its normally open contact is closed, switching to the step-down winding of the transformer, so that the output voltage is about 30V lower than the mains voltage, which is within the normal range.

When the AC voltage is less than 185V and greater than 160V, IC2 outputs a high level, and IC1, IC3, and IC4 all output a low level. At this time, J2 is activated, its normally closed contact is disconnected, and its normally open contact is closed, switching to the transformer's step-up winding. The output voltage is about 30V higher than the AC voltage, which is within the normal range.

In the above three cases, transistor T3 is cut off, capacitor C2 is charged through resistor R, and about 5 minutes later, the voltage of pins ② and ⑥ of IC5 reaches 4V, and pin ③ outputs a low level. BCR is turned on by the trigger voltage to power the compressor.

When the AC voltage is too high (greater than 270V) or too low (less than 160V), IC3 or IC4 outputs a high level, transistor T3 is turned on, capacitor C2 discharges rapidly, the voltage of pins ② and ⑥ of IC5 drops below 2V, pin ③ outputs a high level, and BCR is cut off due to no trigger voltage, stopping powering the compressor.

Component selection and adjustment:

All components are genuine products, and their specifications are shown in the table below.

Adjust RP3 to make IC3 output high level when the mains voltage is 270V, adjust PR4 to make IC4 output high level when the mains voltage is 160V; adjust RP1 to make J1 operate when the mains voltage is 245V, and adjust RP2 to make it operate when the mains voltage is 185V. The above adjustments should be repeated to make them accurate.