Compressor and cooling water pump interlocking control circuit and control method

Abstract

The invention relates to a compressor and cooling water pump interlocking control circuit which comprises a unit starting circuit, a compressor operation circuit, a water pump operation circuit, a compressor protection circuit, a unit restarting circuit, a temperature control circuit and a water flow circuit which are connected to a control power source in parallel. A restarting circuit is matched to control power loss to disconnect a water pump, a temperature control circuit and a water flow circuit are combined to control connection of a corresponding power loss time delay relay, a compressor controller is connected only when a water flow switch monitors a reasonable water volume range, and delayed starting of a compressor is effectively guaranteed; when the refrigerant water temperature and water flow fluctuation exceed a set range, a compressor operation line is disconnected firstly and then a water pump operation line is disconnected in a delayed mode, and it is guaranteed that the compressor is fully cooled; when starting is needed, after a compressor contactor loses power, a switch of a unit restart power-on time-delay relay needs to be closed after the power-on time is met, and restart control and protection are met.

Description

Technical Field

[0001] The invention relates to a compressor control technology, in particular to a compressor and a cooling water pump interlocking control method. Background Art

[0002] With the development of refrigeration technology, the demand for cooling water supply for compressors is getting higher and higher. Traditional compressors and cooling water pumps are turned on and off at the same time. The problem caused by turning on the same time is that they start at the same time, which increases the impact on the power grid. The problem caused by turning off the same time is that the compressor cannot be fully cooled after stopping. In addition, the compressor stops when the water flow fluctuates. Summary of the invention

[0003] The invention provides a compressor and cooling water pump interlocking control method which can start and restart in steps and take restart control into consideration to ensure safe and stable cooling supply by the compressor.

[0004] The technical solution adopted by the present invention is: a compressor and cooling water pump interlocking control circuit, including a unit starting circuit, a compressor operation circuit and a water pump operation circuit respectively connected in parallel to the control power supply, characterized in that: the control power supply is also connected in parallel with a compressor protection circuit, an exhaust gas over-temperature protection controller, a unit restart circuit, a temperature control circuit and a water flow circuit; the compressor protection circuit is connected in series with a water pump thermal relay switch, an air intake low-pressure controller switch, an exhaust gas high-pressure controller switch, an oil pressure difference controller switch, an exhaust gas over-temperature protection controller switch, a compressor thermal relay switch, and a compressor protection relay; the unit starting circuit is connected in series with a first normally open switch of a compressor protection relay, a start button, a stop button and a unit starting power-off delay relay, and the start button is connected in parallel with a normally open switch of a unit starting power-off delay relay; the unit restart circuit is connected in series with a normally closed switch of a compressor contactor and a unit restart power-on delay relay Electrical appliances; the temperature control circuit is connected in series with the normally closed switch of the refrigerant water temperature controller and the temperature control power-off delay relay in sequence; the water pump operation circuit is connected in series with the power-off delay switch of the unit start-up power-off delay relay, the first power-on delay switch of the unit restart power-on delay relay, the power-off delay switch of the temperature control power-off delay relay and the water pump contactor, and the first power-on delay switch of the unit restart power-on delay relay is connected in parallel with the first normally open switch of the water pump contactor; the water flow circuit is connected in series with the water flow switch and the water flow power-off delay relay in sequence; the compressor operation circuit is connected in series with the second normally open switch of the water pump contactor, the power-off delay switch of the water flow power-off delay relay, the normally open switch of the temperature control power-off delay relay, the second normally open switch of the compressor protection relay, the second power-on delay switch of the unit restart power-on delay relay and the compressor contactor, and the first normally open switch of the compressor contactor is connected in parallel with the second power-on delay switch of the unit restart power-on delay relay.

[0005] The compressor protection circuit is also connected in series with a power monitor switch, and the power monitor is connected to the compressor power supply.

[0006] The oil pressure difference controller heater is also connected to the second normally open switch of the compressor contactor back to the power supply.

[0007] A compressor and cooling water pump interlocking control method, characterized in that: a. Before starting, the water pump thermal relay, the compressor's suction port low-pressure controller, the exhaust port high-pressure controller, the oil pressure difference controller, the exhaust over-temperature protection controller, and the compressor thermal relay are all normal, and their corresponding switches are in the on state; the control power supply is powered on, the compressor protection relay is energized, and the first normally open switch of the compressor protection relay is in the closed state; the unit restart circuit is connected, and the unit restart power-on delay relay is energized. Within the delay time of the unit restart power-on delay relay, the first and second power-on delay switches of the unit restart power-on delay relay are not closed, the water pump operation circuit and the compressor operation circuit are not connected, the water pump contactor and the compressor contactor are not energized, and the water pump and the compressor are not running; b. When the unit starts, press the start button, and after the delay time of the unit restart power-on delay relay has exceeded, the unit start circuit is connected, the unit start power-off delay relay is energized, and the normally open switch of the unit start power-off delay relay is closed to lock the electric start button to keep the unit start circuit connected; at this time, the first and second power-on delay switches of the unit restart power-on delay relay are closed; c. When the refrigerant water delivery temperature of the refrigeration system does not reach the set temperature, when the normally closed switch of the refrigerant water temperature controller on the temperature control circuit remains closed, the temperature control circuit is connected, and the temperature control power-off delay relay is energized; the power-off delay switch of the unit start-up power-off delay relay on the water pump operation circuit is instantaneously closed, and the first power-on delay switch of the unit restart power-on delay relay is closed, and the power-off delay switch of the temperature control power-off delay relay is instantaneously closed, the water pump operation circuit is connected, the water pump contactor is energized, the water pump runs, and the first normally open switch of the water pump contactor is closed to lock the first power-on delay switch of the unit restart delay relay; after the water pump runs, the water flow switch reaches the set water volume range and closes, the water flow circuit is connected, and the water flow power-off delay relay is energized; the water pump contactor on the compressor operation circuit The second normally open switch of the unit is closed, the power-off delay switch of the water flow rate power-off delay relay is closed, the normally open switch of the temperature control power-off delay relay is closed, the second power-on delay switch of the unit restart delay relay is closed, the compressor operation circuit is connected, the compressor contactor is powered, the compressor is running, the second normally open switch of the compressor protection relay is closed and the second power-on delay switch of the unit restart delay relay is locked; at this time, the normally closed switch of the compressor on the unit restart circuit is opened, the unit restart circuit is disconnected, the unit restart power-on delay relay loses power, the first and second power-on delay switches of the unit restart power-on delay relay are delayed to disconnect, and the water pump operation circuit and the compressor operation circuit are locked and connected by the first normally open switch of the water pump contactor and the first normally open switch of the compressor contactor; d. When the water flow rate drops and fluctuates, the water flow switch on the water flow line is opened, the water flow line is disconnected, and the water flow power-off delay relay is powered off. According to the duration of the fluctuation, when the fluctuation ends, if the fluctuation time is less than the delay time of the water flow power-off delay relay, the water flow power-off delay relay is powered on again, and the power-off delay switch of the water flow power-off delay relay remains on, and the compressor keeps running. If the fluctuation time exceeds the delay time of the water flow power-off delay relay, the power-off delay switch of the water flow power-off delay relay is disconnected, and the compressor contactor is powered off. At this time, the normally closed contactor of the compressor in the unit restart circuit is closed, and the unit restart power-on delay relay is powered on. The first and second power-on delay switches of the unit restart power-on delay relay on the water pump operation circuit and the compressor operation circuit need to be closed after a delay to realize the restart of the unit; e. When the refrigerant water delivery temperature of the refrigeration system reaches the set temperature, the normally closed switch of the refrigerant water temperature controller is disconnected, the temperature control circuit is disconnected, and the temperature control power-off delay relay loses power; the normally open switch of the temperature control power-off delay relay on the compressor operation circuit opens instantaneously, the compressor contactor loses power, and the compressor stops instantly; the power-off delay switch of the temperature control power-off delay relay on the water pump operation circuit opens with a delay, the water pump contactor is powered off with a delay, and the water pump is stopped with a delay; f. Restart control: when the compressor operation circuit is disconnected, the compressor contactor loses power, and the compressor stops, the normally closed switch of the compressor contactor remains closed, the unit restart circuit is connected, and the unit restart power-on delay relay requires a delay time. After the delay time is over, the first and second power-on delay switches of the unit restart power-on delay relay are closed to achieve the delay of restart; g. Fault protection: the water pump thermal relay switch, the air intake low-pressure controller switch, the exhaust high-pressure controller switch, the oil pressure difference controller switch, the exhaust over-temperature protection controller switch, and the compressor thermal relay switch are disconnected by their respective controllers and relay signals, the compressor protection circuit is disconnected, the compressor protection relay loses power, the first and second normally open switches of the compressor protection relay remain open, and the unit start circuit and the compressor operation circuit remain disconnected.

[0008] The present invention adopts a compressor protection circuit to control the unit start-up circuit, cooperates with the unit restart circuit to control the water pump operation circuit that is disconnected due to power failure, and combines the temperature control circuit and the water flow circuit to control the corresponding power failure delay relay to be turned on according to the refrigerant water temperature and water flow fluctuation parameters respectively. Under normal circumstances, the water pump contactor is controlled to be turned on, and the compressor controller is turned on only when the water flow switch monitors a reasonable water volume range, effectively ensuring the delayed start of the compressor and avoiding the large current shock of synchronous start; when the refrigerant water temperature and water flow fluctuation exceed the set range, the compressor operation circuit is disconnected first, and then the water pump operation circuit is disconnected with a delay to ensure that the compressor is fully cooled; when it is necessary to start, it is necessary to meet the unit restart power delay time after the compressor contactor loses power before the switch of the unit restart power delay relay meets the delayed power-on time, thereby continuing to start the water pump, and then start the compressor, to meet the restart control and protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a circuit diagram of the present invention.

[0010] In the figure: control power supply 1, compressor protection circuit 2, unit start circuit 3, unit restart circuit 4, temperature control circuit 5, water pump operation circuit 6, water flow circuit 7, compressor operation circuit 8, water pump thermal relay switch FR1, power monitor switch K, suction port low pressure controller switch LP, exhaust port high pressure controller switch HP, oil pressure difference controller OP, oil pressure difference controller switch OP-1, exhaust over-temperature protection controller switch STW, compressor thermal relay switch FR2, compressor protection relay KA, compressor protection relay first normally open switch KA-1, compressor protection relay second normally open switch KA-2, start button SB1, stop button SB2, remote start button SB3, remote stop button SB4, unit start power failure delay relay KT1, unit start power failure delay relay normally open switch KT1-1, unit start power-off delay relay power-off delay switch KT1-2, unit restart power-on delay relay KT2, unit restart power-on delay relay first power-on delay switch KT2-1, unit restart power-on delay relay second power-on delay switch KT2-2, refrigerant water temperature controller normally open switch WK, temperature control power-off delay relay KT4, temperature control power-off delay relay power-off delay switch KT4-1, temperature control power-off delay relay normally open switch KT4-2, water flow switch LKB, water flow power-off delay relay KT3, water pump contactor KM1, water pump contactor first normally open switch KM1-1, water pump contactor second normally open switch KM1-2, compressor contactor KM2, compressor contactor first normally open switch KM2-1, compressor contactor second normally open switch KM2-2. Rating DETAILED DESCRIPTION

[0011] The following is a further description with reference to the accompanying drawings.

[0012] Figure 1 As shown: a compressor and cooling water pump interlocking control circuit, including a compressor protection circuit 2, a unit start circuit 3, a unit restart circuit 4, a temperature control circuit 5, a water pump operation circuit 6, a water flow circuit 7, a compressor operation circuit 8 and an oil pressure difference controller OP which are respectively connected in parallel to a control power supply 1.

[0013] The compressor protection circuit 2 is connected in series in sequence: the water pump thermal relay switch FR1, the power monitor switch K, the suction port low-pressure controller switch LP, the exhaust port high-pressure controller switch HP, the oil pressure difference controller switch OP-1, the exhaust over-temperature protection controller switch STW, the compressor thermal relay switch FR2, and the compressor protection relay KA. The oil pressure difference controller heater is also connected to the compressor contactor's second normally open switch KM2-2 to return the control power supply.

[0014] The first normally open switch KA-1 of the compressor protection relay, the start button SB1, the remote stop button SB3, the stop button SB2 and the unit start power failure delay relay KT1 are connected in series on the unit start line 3, and the start button is connected in parallel with the unit start power failure delay relay normally open switch KT1-1. The compressor contactor normally closed switch KM2-1 and the unit restart power-on delay relay KT2 are connected in series on the unit restart circuit 3.

[0015] The temperature control circuit 4 is connected in series with the refrigerant water temperature controller normally closed switch WK and the temperature control power-off delay relay KT4.

[0016] The water pump operation line 5 is connected in series in sequence with the unit start power-off delay relay power-off delay switch KT1-2, the unit restart power-on delay relay first power-on delay switch KT2-1, the temperature control power-off delay relay power-off delay switch KT4-1 and the water pump contactor KM1, and the unit restart power-on delay relay first power-on delay switch KT2-1 is connected in parallel with the water pump contactor first normally open switch KM1-1.

[0017] The water flow line 7 is connected in series with a water flow switch LKB and a water flow power-off delay relay KT3.

[0018] The compressor operation line 8 is connected in series in sequence with the second normally open switch KM1-2 of the water pump contactor, the water flow power-off delay relay power-off delay switch KT3-1, the temperature control power-off delay relay normally open switch KT4-2, the compressor protection relay second normally open switch KA-2, the unit restart power-on delay relay second power-on delay switch KT2-2 and the compressor contactor KM2, and the first normally open switch KM2-2 of the compressor contactor is connected in parallel with the second power-on delay switch KT2-2 of the unit restart power-on delay relay.

[0019] In this embodiment, the power monitor is connected to the compressor power supply.

[0020] The control method of the compressor and cooling water pump interlocking control circuit is: a. Before starting, the water pump thermal relay, the compressor's suction port low-pressure controller, the exhaust port high-pressure controller, the oil pressure difference controller, the exhaust over-temperature protection controller, and the compressor thermal relay are all normal, and their corresponding switches are in the on state; the control power supply is powered on, the compressor protection relay is energized, and the first normally open switch of the compressor protection relay is in the closed state; the unit restart circuit is connected, and the unit restart power-on delay relay is energized. Within the delay time of the unit restart power-on delay relay, the first and second power-on delay switches of the unit restart power-on delay relay are not closed, the water pump operation circuit and the compressor operation circuit are not connected, the water pump contactor and the compressor contactor are not energized, and the water pump and the compressor are not running; b. When the unit starts, press the start button, and after the delay time of the unit restart power-on delay relay has exceeded, the unit start circuit is connected, the unit start power-off delay relay is energized, and the normally open switch of the unit start power-off delay relay is closed to lock the electric start button to keep the unit start circuit connected; at this time, the first and second power-on delay switches of the unit restart power-on delay relay are closed; c. When the refrigerant water delivery temperature of the refrigeration system does not reach the set temperature, when the normally closed switch of the refrigerant water temperature controller on the temperature control circuit remains closed, the temperature control circuit is connected, and the temperature control power-off delay relay is energized; the power-off delay switch of the unit start-up power-off delay relay on the water pump operation circuit is instantaneously closed, and the first power-on delay switch of the unit restart power-on delay relay is closed, and the power-off delay switch of the temperature control power-off delay relay is instantaneously closed, the water pump operation circuit is connected, the water pump contactor is energized, the water pump runs, and the first normally open switch of the water pump contactor is closed to lock the first power-on delay switch of the unit restart delay relay; after the water pump runs, the water flow switch reaches the set water volume range and closes, the water flow circuit is connected, and the water flow power-off delay relay is energized; the water pump contactor on the compressor operation circuit The second normally open switch of the unit is closed, the power-off delay switch of the water flow rate power-off delay relay is closed, the normally open switch of the temperature control power-off delay relay is closed, the second power-on delay switch of the unit restart delay relay is closed, the compressor operation circuit is connected, the compressor contactor is powered, the compressor is running, the second normally open switch of the compressor protection relay is closed and the second power-on delay switch of the unit restart delay relay is locked; at this time, the normally closed switch of the compressor on the unit restart circuit is opened, the unit restart circuit is disconnected, the unit restart power-on delay relay loses power, the first and second power-on delay switches of the unit restart power-on delay relay are delayed to disconnect, and the water pump operation circuit and the compressor operation circuit are locked and connected by the first normally open switch of the water pump contactor and the first normally open switch of the compressor contactor; d. When the water flow rate drops and fluctuates, the water flow switch on the water flow line is opened, the water flow line is disconnected, and the water flow power-off delay relay is powered off. According to the duration of the fluctuation, when the fluctuation ends, if the fluctuation time is less than the delay time of the water flow power-off delay relay, the water flow power-off delay relay is powered on again, and the power-off delay switch of the water flow power-off delay relay remains on, and the compressor keeps running. If the fluctuation time exceeds the delay time of the water flow power-off delay relay, the power-off delay switch of the water flow power-off delay relay is disconnected, and the compressor contactor is powered off. At this time, the normally closed contactor of the compressor in the unit restart circuit is closed, and the unit restart power-on delay relay is powered on. The first and second power-on delay switches of the unit restart power-on delay relay on the water pump operation circuit and the compressor operation circuit need to be closed after a delay to realize the restart of the unit; e. When the refrigerant water delivery temperature of the refrigeration system reaches the set temperature, the normally closed switch of the refrigerant water temperature controller is disconnected, the temperature control circuit is disconnected, and the temperature control power-off delay relay loses power; the normally open switch of the temperature control power-off delay relay on the compressor operation circuit opens instantaneously, the compressor contactor loses power, and the compressor stops instantly; the power-off delay switch of the temperature control power-off delay relay on the water pump operation circuit opens with a delay, the water pump contactor is powered off with a delay, and the water pump is stopped with a delay; f. Restart control: when the compressor operation circuit is disconnected, the compressor contactor loses power, and the compressor stops, the normally closed switch of the compressor contactor remains closed, the unit restart circuit is connected, and the unit restart power-on delay relay requires a delay time. After the delay time is over, the first and second power-on delay switches of the unit restart power-on delay relay are closed to achieve the delay of restart; g. Fault protection: the water pump thermal relay switch, the air intake low-pressure controller switch, the exhaust high-pressure controller switch, the oil pressure difference controller switch, the exhaust over-temperature protection controller switch, and the compressor thermal relay switch are disconnected by their respective controllers and relay signals, the compressor protection circuit is disconnected, the compressor protection relay loses power, the first and second normally open switches of the compressor protection relay remain open, and the unit start circuit and the compressor operation circuit remain disconnected.

Claims

1. A compressor and cooling water pump interlocking control circuit, comprising a unit starting circuit, a compressor operation circuit and a water pump operation circuit respectively connected in parallel to a control power supply, characterized in that: The control power supply is also connected in parallel with a compressor protection circuit, an exhaust over-temperature protection controller, a unit restart circuit, a temperature control circuit and a water flow circuit; the compressor protection circuit is connected in series with a water pump thermal relay switch, an air intake low-pressure controller switch, an exhaust high-pressure controller switch, an oil pressure difference controller switch, an exhaust over-temperature protection controller switch, a compressor thermal relay switch, and a compressor protection relay; the unit start circuit is connected in series with the first normally open switch of the compressor protection relay, a start button, a stop button and a unit start power-off delay relay, and the start button is connected in parallel with the normally open switch of the unit start power-off delay relay; the unit restart circuit is connected in series with the normally closed switch of the compressor contactor and the unit restart power-on delay relay; the temperature control circuit is connected in series with the normally closed switch of the refrigerant water temperature controller and the temperature control power-off delay relay The water pump operation circuit is connected in series with the power-off delay switch of the unit start-up power-off delay relay, the first power-on delay switch of the unit restart power-on delay relay, the power-off delay switch of the temperature control power-off delay relay and the water pump contactor, and the first power-on delay switch of the unit restart power-on delay relay is connected in parallel with the first normally open switch of the water pump contactor; the water flow switch and the water flow power-off delay relay are connected in series in sequence; the compressor operation circuit is connected in series with the second normally open switch of the water pump contactor, the power-off delay switch of the water flow power-off delay relay, the normally open switch of the temperature control power-off delay relay, the second normally open switch of the compressor protection relay, the second power-on delay switch of the unit restart power-on delay relay and the compressor contactor, and the first normally open switch of the compressor contactor is connected in parallel with the second power-on delay switch of the unit restart power-on delay relay.

2. A compressor and cooling water pump interlocking control circuit according to claim 1, characterized in that: The compressor protection circuit is also connected in series with a power monitor switch, and the power monitor is connected to the compressor power supply.

3. A compressor and cooling water pump interlocking control circuit according to claim 1, characterized in that: The oil pressure difference controller heater is also connected to the second normally open switch of the compressor contactor back to the power supply.

4. A compressor and cooling water pump interlocking control method, characterized in that: a. Before starting, the water pump thermal relay, the compressor's suction port low-pressure controller, the exhaust port high-pressure controller, the oil pressure difference controller, the exhaust over-temperature protection controller, and the compressor thermal relay are all normal, and their corresponding switches are in the on state; the control power supply is powered on, the compressor protection relay is energized, and the first normally open switch of the compressor protection relay is in the closed state; the unit restart circuit is connected, the unit restart power-on delay relay is energized, and within the delay time of the unit restart power-on delay relay, the first and second power-on delay switches of the unit restart power-on delay relay are not closed, the water pump operation circuit and the compressor operation circuit are not connected, the water pump contactor and the compressor contactor are not energized, and the water pump and the compressor are not running; b. When the unit is started, the start button is pressed, and after the delay time of the unit restart power-on delay relay has exceeded, the unit start circuit is connected, the unit start power-off delay relay is energized, and the normally open switch of the unit start power-off delay relay is closed to lock the electric start button to keep the unit start circuit connected; at this time, the first and second power-on delay switches of the unit restart power-on delay relay are closed; c. When the refrigerant water delivery temperature of the refrigeration system does not reach the set temperature, when the normally closed switch of the refrigerant water temperature controller on the temperature control circuit remains closed, the temperature control circuit is connected, and the temperature control power-off delay relay is energized; the power-off delay switch of the unit start-up power-off delay relay on the water pump operation circuit is instantaneously closed, and the first power-on delay switch of the unit restart power-on delay relay is closed, and the power-off delay switch of the temperature control power-off delay relay is instantaneously closed, the water pump operation circuit is connected, the water pump contactor is energized, the water pump runs, and the first normally open switch of the water pump contactor is closed to lock the first power-on delay switch of the unit restart delay relay; After the water pump is running, the water flow switch reaches the set water volume range and closes, the water flow circuit is connected, and the water flow power-off delay relay is energized; the second normally open switch of the water pump contactor on the compressor operation circuit is closed, the water flow power-off delay relay power-off delay switch is closed, the temperature control power-off delay relay normally open switch is closed, the second energized delay switch of the unit restart delay relay is closed, the compressor operation circuit is connected, the compressor contactor is energized, the compressor runs, and the second normally open switch of the compressor protection relay is closed to lock the second energized delay switch of the unit restart delay relay; At this time, the normally closed switch of the compressor on the unit restart circuit is opened, the unit restart circuit is disconnected, the unit restart power-on delay relay loses power, the first and second power-on delay switches of the unit restart power-on delay relay are delayed to disconnect, and the water pump operation circuit and the compressor operation circuit are locked and kept connected by the first normally open switch of the water pump contactor and the first normally open switch of the compressor contactor; d. When the water flow rate drops and fluctuates, the water flow switch on the water flow line is opened, the water flow line is disconnected, and the water flow power-off delay relay is powered off. According to the duration of the fluctuation, when the fluctuation ends, if the fluctuation time is less than the delay time of the water flow power-off delay relay, the water flow power-off delay relay is powered on again, and the power-off delay switch of the water flow power-off delay relay remains on, and the compressor keeps running. If the fluctuation time exceeds the delay time of the water flow power-off delay relay, the power-off delay switch of the water flow power-off delay relay is disconnected, and the compressor contactor is powered off. At this time, the normally closed contactor of the compressor in the unit restart circuit is closed, and the unit restart power-on delay relay is powered on. The first and second power-on delay switches of the unit restart power-on delay relays on the water pump operation circuit and the compressor operation circuit need to be closed after a delay to realize the restart of the unit; e. When the refrigerant water delivery temperature of the refrigeration system reaches the set temperature, the normally closed switch of the refrigerant water temperature controller is disconnected, the temperature control circuit is disconnected, and the temperature control power-off delay relay loses power; The normally open switch of the temperature control power-off delay relay on the compressor operation circuit opens instantaneously, the compressor contactor is powered off, and the compressor stops instantly. The temperature control power-off delay relay on the water pump operation circuit opens with a delay, the water pump contactor is powered off with a delay, and the water pump stops with a delay. f. Restart control: when the compressor operation circuit is disconnected, the compressor contactor loses power, and the compressor stops, the normally closed switch of the compressor contactor remains closed, the unit restart circuit is connected, and the unit restart power-on delay relay requires a delay time. After the delay time ends, the first and second power-on delay switches of the unit restart power-on delay relay are closed to achieve the delay of restart; g. Fault protection: the water pump thermal relay switch, the air intake low-pressure controller switch, the exhaust high-pressure controller switch, the oil pressure difference controller switch, the exhaust over-temperature protection controller switch, and the compressor thermal relay switch are disconnected by their respective controllers and relay signals, the compressor protection circuit is disconnected, the compressor protection relay loses power, the first and second normally open switches of the compressor protection relay remain open, and the unit start-up circuit and the compressor operation circuit remain disconnected.

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