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instruction manual
2.4 Adjustment system
Compressors with DOL starter
The adjustment system includes:
•
Non-return valve (CV)
Pressure switch (MDR) with solenoid valves (6) and On/Off button (S1)
•
The air pressure switch (MDR) opens and closes its contacts at pre-set pressures. during operation un-
der load the contacts are closed: the motor is running.
When the pressure in the compressed air tank reaches the pre-set value, both the contacts and the pres-
sure release valve (6) will be open. The motor will stop, the compressed air on the compressor's delivery
side will be discharged into the atmosphere and the non-return valve (CV) will close to prevent the tank
discharging.
When the pressure present in the compressed air tank drops to the minimum pre-set value, the contacts
of the pressure switch and the pressure discharging valve (6) will close. The motor will re-start and the
compressed air will again be fed to the tank.
Compressors with STAR-DELTA starter
The adjustment system includes:
•
Non-return valve (CV)
•
Air pressure switch (MDR)
On/Off switch (S1)
•
•
Solenoid valve (Y1)
The air pressure switch (MDR) opens and closes its contacts at pre-set pressures. during operation un-
der load the contacts are closed: the motor runs and the solenoid valve (Y1) is energised, preventing the
compressed air from flowing towards the discharger.
When pressure in the air tank reaches the pre-set maximum value, the pressure switch (MDR) contacts
will open. The motor will stop and the solenoid valve (Y1) will be de-energised. The tank's compressed
air will flow, through the solenoid valve, to the piston that will control the opening of the discharge valve.
The non-return valve (CV) will close to prevent the tank from discharging the compressed air.
When the pressure present in the compressed air tank drops to the minimum pre-set value, the contacts
of the pressure switch will close. The motor will re-start and, once the star-triangle starter device has
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