Chicago Pneumatic CPVS 50, CPVS 60, CPVS 40 Principle of the pressure regulation by variable speed

Fig. 14a

The principle of the pressure regulation by variable speed

Pressure	Controller	Drive	Motor	Compressor		Tank
required					unit

Frequency speed

Pressure sensor

System

• Pressure regulation for low rates of flow • Energy saving

For an air consumption rate lower than the minimum rate of flow for the machine, the pressure is adjusted by the machine's time- delayed START/STOP controls.

Since the operation element cannot function below a certain speed (corresponding to the minimum output), the compressor conti- nues to run and compress at the minimum speed until the pres- sure reaches the limit called "Indirect shutdown ".

Once this threshold has been reached, the motor will stop, the machine will go into stand-by mode after a certain period of inactivity and the full drainage process will be carried out.The pressure then drops towards the indicated pressure and, at the end of the minimum time delay (since reaching the no-load pres- sure), the drive allows the motor to restart. The pressure then rises again and the cycle starts over (fig. 14 d).

To avoid pumping the system - frequent stop / start - drainage time may be increased

(cf. notice AIRLOGIC).

For demand of compressed air within the machine's flow range - min flow to max flow, the frequency converter or the variable speed drive feed the motor in order to ensure that it turns at the speed required to supply air demand both for pressure and flow.

It is used to adjust the power supply to the motor (and thus the machine) to the exact power requirement for the compression of the air, without a drainage stage being necessary.

COMMENT :

Energy savings are increased if machine maintenance is carried out in accordance with the maintenance instructions and frequency.

01/2008	Chicago Pneumatic Compressors
Page 18	62 305 258 65