Do you know the distress signal of screw air compressor

The screw air compressor will inevitably have various problems during long-term use, and an alarm will be triggered at this time. Especially in the high temperature in summer, screw air compressors are more likely to appear frequently. So, what are some of the alarms of the air compressor? What is the difference in urgency and severity? Come and find out!

Secondary alarm

Oil level alarm: After the compressor is started, if the oil level is higher than 1/3 (low oil level switch), continue, otherwise lower than 1/3 will trigger the low oil level pre-signal, and continue for 20s continuously, then alarm; low oil level Alarm; and run the stop program.

Oil pressure difference alarm: After the compressor is started, if the oil filter pressure difference is less than 2bar, it will continue, otherwise it will alarm; the oil pressure difference is large; and run the stop program.

High and low pressure difference alarm: the compressor motor is energized, and the high and low pressure difference detection starts in the 20s. If the high and low pressure difference is greater than 1.5bar, continue, otherwise the alarm; the oil supply pressure is insufficient; and the solenoid valve SV1 is de-energized and the liquid pipe is cut The valve is de-energized, and the motor is de-energized; after the compressor is started, if the high and low pressure difference is greater than 4bar, it will continue, otherwise it will alarm; the oil supply pressure is insufficient; and the stop program will run.

Built-in high temperature alarm: the compressor is powered by PTC control. If the built-in PTC thermistor detects that the motor temperature is lower than 110±5℃ and the internal exhaust port temperature is lower than 90±5℃, continue, otherwise it will alarm "built-in temperature alarm" It also provides a signal that the compressor motor contactor cannot be closed; during compressor operation, if the built-in PTC thermistor detects that the motor temperature is lower than 130±5℃ and the internal exhaust port temperature is lower than 110±5℃, continue, otherwise an alarm will be issued. Built-in temperature alarm" and run the stop program.

Excessive exhaust temperature protection: During compressor operation, if the exhaust temperature is lower than the design alarm temperature of 100℃, continue, otherwise it will be higher than 100℃ and continue for 2 minutes, then it will alarm "Exhaust temperature is high" and stop running program.

Excessive discharge pressure protection: During compressor operation, if the discharge pressure is lower than the design alarm pressure 2.2MPa (value, corresponding to different systems), it will continue, otherwise the discharge pressure is high and the stop program will run.

Low return air pressure protection: during compressor operation, if the return air pressure is higher than the design alarm pressure 0.03MPa (value, corresponding to different systems), then continue, otherwise the return air pressure low pre-signal will be triggered and continue for 10s, then an alarm "Return air pressure is low" and run the stop program.

(Related to the bypass solenoid valve; abnormal low-pressure bypass and abnormal low-pressure load shedding shall be explained in the corresponding control plan and combined with low-pressure alarm judgment)

Overload: The power is too high, exceeding the set value, output abnormal signal, alarm; compressor is overloaded. (The PLC project is not tested separately, and the overcurrent protection is monitored by thermal relay)

Phase sequence: The phase sequence protector outputs an abnormal signal and alarms the abnormal phase sequence.

Overcurrent: The current is too high, exceeding the set value, output abnormal signal, alarm; compressor transition. (The PLC project is not tested separately, and the overcurrent protection is monitored by thermal relay)

Special Note

Alarm level:

Zero-level alarm: interlocked to stop and enter the protection state, requiring manual reset by the mechanical switch. (Emergency alarm)

Level 1 alarm: prompts the alarm and stops operation as required, and needs to be received to eliminate the fault and reset manually; (protection alarm)

Secondary alarm: prompts the alarm and stops operation as required, and automatically recovers after checking and eliminating the abnormality; (reset the alarm)

　Three-level alarm: It only prompts and does not participate in the action, and the alarm needs to be cleared manually. Previous indication status (abnormal alarm)

Temperature protection: A total of three levels, followed by load shedding, external exhaust temperature, and built-in PTC protection (exhaust, motor). Related premises: Compressor PTC control and power supply: Screw compressors have two power sources, each of which is the main power supply Power supply (380V) and protection power supply (220V). PTC provides power for the protection power supply. Compressor motor is energized: the main power supply of the screw compressor is connected. After the compressor starts: the screw compressor is loaded to 50% according to the normal start-up procedure to complete the start. During compressor operation: the screw compressor operates in three load states: 50%, 75%, and 100%.