Reverse Protection Control - Hitachi RCUE40AG2 Service Manual

Control system


Reverse protection control:

3 phase input status
detection
UNIT STATUS
OFF
UNIT STATUS
ON
pag. 55

4.5. Reverse protection control

Screw compressor compresses the refrigerant to a determined pressure by decreasing
the space formed by male/female rotor and slide valve. If the rotor revolution direction
is reversed, the suction side and discharge side are reversed and the functioning of the
compressor will not be correct.
Therefore, 3 phase input status is detected and operation is not performed in case of
reverse phase or open phase.
Reverse phase
Open phase
Reverse phase
Open phase
SMGB0003 rev.0-01/2007
T phase:
open phase
R phase:
open phase
S phase:
open phase
T phase:
open phase
R phase:
open phase
S phase:
open phase

Alarm
4 4

Alarm
UNIT GOES OFF