How to connect two air compressors

The connection mode of two air compressors is mainly parallel and tandem two, depending on your gas needs, site conditions and equipment characteristics. The following is a detailed description of the two connection methods and operating instructions:

1. parallel connection (recommended for increased gas supply)

applicable Scenarios: Large flow demand, stable gas supply pressure, or as standby equipment.

1. Electrical wiring steps

• main circuit connection:
  • connect the three-phase four-wire power lines of each air compressor to their respective control boxes to ensure reliable grounding of the ground wire.
  • The three-core wire of the motor is connected to the lower end terminal of the contactor, and the phase sequence is consistent (if the motor is reversed, replace any two-phase live wire).
• Control loop wiring:
  • connect one phase live wire to the stop button, and then connect to one end of the contactor coil through the start button.
  • The other end of the coil is connected to the other phase live wire through the normally closed point of the thermal relay and the normally closed point of the pressure switch to form a complete control loop.
• Parallel joint control setting:
  • use communication lines (such as RS485) to connect the controllers of two air compressors, and set the master-slave mode.
  • Configure the unloading pressure (0.02MPa higher than the target pressure is recommended) and the loading pressure (0.02MPa lower than the target pressure) to ensure stable pressure.

2. Key points of pipeline connection

• the exhaust pipe is connected to the main pipe from above to avoid backflow of condensed water.
• Pipe diameter is not less than the air compressor exhaust diameter, install isolation ball valve (check valve is not required).

3. Control system settings

• set the "target pressure", "unloading pressure" and "loading pressure" parameters to ensure that the three-pressure relationship is: unloading pressure> target pressure> loading pressure, and the differential pressure is recommended to be greater than 0.7BAR.
• Enable the joint control mode, set the rotation time (such as 60 minutes), and balance the running time of the two devices.

2. series connection (recommended for improving gas quality)

applicable Scenarios: High requirements for gas purity, multi-stage filtration or drying.

1. Electrical wiring steps

• start sequence control:
  • after the first air compressor is started, the second air compressor is controlled to start through the time delay relay (delay 5-8 seconds).
  • The pressure switch of the second air compressor should be slightly higher than the first to prevent premature shutdown.
• Control loop interlocking:
  • the pressure switches of the two air compressors are connected in series in the control circuit to ensure that the pressure is stopped at the same time when the pressure exceeds the limit.
• Communication joint control setting:
  • use the communication line to connect the controller, and set the linkage delay time and rotation time.
  • The loading pressure of the second air compressor should be 0.02MPa lower than that of the first one to ensure seamless switching.

2. Key points of pipeline connection

• the exhaust pipe of the first air compressor is connected to the air inlet of the second air compressor to form a series path.
• Install high-efficiency filters and dryers in series pipes to improve gas quality.

3. Control system settings

• set the target pressure of the first air compressor slightly higher than the second to ensure that the gas is fully treated.
• Enable the joint control mode and set the joint delay time (default 10 seconds) to avoid frequent start and stop.

3. General Installation Precautions

1. computer room site selection:
   • avoid high temperature, humid and dusty environment and ensure good ventilation (temperature ≤ 40 ℃).
2. water cooling system:
   • the water inlet pipe is equipped with a 40-mesh water filter, and the water inlet and outlet pipes are equipped with isolation ball valves and winter drain valves.
   • Control the cooling water pressure (0.3-0.5MPa), temperature difference (≥ 0.15MPa) and temperature (≤ 35 ℃).
3. Ventilation and heat dissipation:
   • low-power units can be equipped with exhaust fans, and high-power units need to use air duct to draw air (the section is consistent with the vent).
4. Safety grounding:
   • ensure that the resistance of the ground wire meets the requirements to prevent the risk of electric shock.

4. common problems and solutions

through the above steps, you can flexibly choose parallel or series connection according to actual needs to ensure the efficient and safe operation of the two air compressors. If there are further questions, it is recommended to contact the equipment manufacturer to provide technical support for specific models.