Screw Air Compressor Case in Israel - INVT GD300-01 Series Drive

Abstract: This paper introduces the feature of screw air compressor, INVT GD300-01 series special inverter for compressor, and the successful application in Israel.

Key words: screw air compressor, GD300-01, PID, constant pressure

1.Foreword

A rotary-screw compressor is a type of gas compressor which is based on a rotary-type positive-displacement mechanism. It is commonly used to replace piston compressors in either large industrial applications or high-power air tools where large volume of high-pressure air is needed. The traditional pressure control method is loading or unloading, which causes pressure fluctuation, energy waste. The use of frequency inverter for constant pressure control is the current mainstream.

Fig.1 Working process of screw air compressor

2.System requirements

The Israeli air compressor factory has more than three decades of experience in the design and production of air compressors.Their technical requirements are as follows:

(1) Built-in PID function:

1) Preset a pressure value on HMI so that the inverter automatically can adjust the speed according to the feedback pressure to make the pressure constant.

2) No controller needed.

(2) Valve control:

If measured pressure＜setting pressure（8.5bar）, the inlet valve opens;

If measured pressure≥9 bar, the inlet valve closes;

(3) Sleep mode:

If the inlet valve is closed, set pressure（8.5bar）≤measured pressure＜9 bar.After 120 seconds delay time, inverter sleep.

(4) Cooling fan control:

Be able to measure the temperature of compressor, if temperature ≥80℃, start the cooling fan, if temperature ＜75℃, stop the cooling fan.

(5) Over pressure protection:

≥10 bar, display alarm on HMI, continue to work

≥10.5 bar, display alarm on HMI, shut down

(6) Over heat protection:

≥98℃, display alarm on HMI, then continue to work.

≥105℃, display alarm on HMI, then shut down.

(7) Maintenance time alarm：

Be able to set maintenance time, alarm when it is reached

(8) Other protection:

Pressure sensor disconnected alarm, temperature sonsor disconnected alarm, Emergency stop etc.

(9) GD300-01 series inverter + HMI meets all the requirements of customer.

3.System scheme

Fig.2 System diagram

Supplied list:

4.Parameters setting