OPERATING INSTRUCTIONS
CO
2
/NH
3
CASCADE UNIT
250 - 1000 KW
_551511_om_kas_gbr_1_.doc 15
1.6.2.4 Checking the direction of rotation of the
driving motor
1.6.2.5 Checking the direction of rotation of the oil
pump motor
The oil pump is started with the driving motor
electrically blocked (service). The stop valves are in
the operating position.
Warning!
The coupling must not yet connect motor
and compressor!
The direction of the arrow given for the oil pump
must correspond to the direction of rotation of the
electric motor.
• Secure the electric switchgear so as to prevent
the compressor driving motor from being
switched on accidentally.
Caution!
Since the slide ring shaft seal of the oil
pump is dependent on the direction of
rotation and can be damaged when this
direction is wrong, checking must be
reduced to a very short running period
(less than 2 seconds).
• With the control slide in the MIN or MAX
position, it should be possible to rotate the
compressor shaft easily and smoothly by hand.
When checking the direction of rotation of the
compressor driving motor pay attention to the
conditions for switching the compressor on.
The adjusted differential pressure between the oil
pump discharge side and the suction side of the oil
pressure control valve is checked with the oil pump
rotating in the correct direction. It must not be lower
than the specified setpoint of 3.5 + 0.5 bar.
While the compressor is not running and the oil has
not yet reached the operating temperature, the
differential pressure can be slightly higher than the
indicated value.
The differential pressure can be changed by rotating
the spindle on the oil pressure control valve. (The
differential pressure is increased by turning it
inwards and vice versa).
fig. 2: Motor direction of rotation
A Compressor
1.6.2.6 Adjustment of oil pressure
B Motor
Before the compressor drive motor and therefore
the unit can be started, the oil pressure must be set
correctly by adjusting the oil pressure regulating
valve (075).
• The compressor driving motor is operated in
star-delta connection for a short period in the
operating mode "1 (manual + manual)". After
that the compressor driving motor has to switch
off.
For adjustment only the oil pump must be started.
For units equipped with a Grasso System Control
(GSC) please select operation mode “service mode”.
• If the direction of rotation of the motor is
wrong, it should be corrected while the electric
switchgear is secured to prevent the motor from
being switched on accidentally. The motor must
then idle for at least 1h.
The set value of the oil differential pressure should
be taken from the P+I-diagram of the specific
project. Normally the set value is Δp = 2-3 bar (oil
pressure Pos (110) – discharge pressure Pos (105)).
• The coupling protection must be in place during
this running-in period as required in the labour
safety regulations.
The differential pressure can be changed by rotating
the spindle on the oil pressure regulating valve (the
differential pressure is increased by turning it
inwards and vice versa).
• After checking the direction of rotation of the
driving motor the coupling may be connected
with the motor.
To Next Page
Loading...
