Standard Screw Compressor - RWB Series
3-2
M&M
R
EFRIGERATION
I
NC
.
Lubrication System
The RWB screw compressor is designed to be self-lubricating. The oil being supplied to
the compressor is at discharge pressure and the oil porting to all parts of the compressor
is below discharge pressure. The normal process of gas compression allows the com-
pressor to act as its own oil pump. An oil pump is required to pre-lubricate the bearings
and allow slide valve control during startup. Under operating conditions where the differ-
ential pressure (discharge - suction) is too low, a cycling or full lube oil pump is required.
The CCS control for the different lubrication system options is as follows.
Oil Pump Configuration
• Pre-Lube Pump - For normal operations an oil pump is only required to pre-lubri-
cate the bearings and to supply pressure to move the Vi slide stop and the capacity
slide valve when the compressor motor is not running. The pre-lube oil pump is
started before the motor is started and stopped when the starting sequence is com-
plete. The oil pump will be restarted when the compressor is stopped to allow the
slide valve and Vi slide stop to be repositioned in anticipation of the next start.
• Cycling Oil Pump - The cycling oil pump is designed to provide those high stage
applications that operate with normal to low differential pressure ( discharge - suc-
tion) with adequate compressor lubrication. The oil pump is started to pre-lubricate
the bearings and to supply pressure to move the Vi slide stop and the capacity slide
valve when the compressor motor is not running. Once the starting sequence is
complete the oil pump is stopped whenever the differential pressure is greater than
95 PSID. The pump will restart whenever the differential pressure drops below 85
PSID.
The pump will turn off once the differential pressure (DP-SP) is greater than 95
PSID. The oil pump will be restarted if the differential pressure drops below 85
PSID.
• Full Lube -The full lube oil pump is used on booster compressors or whenever the
differential ( discharge - suction) is consistently low. The oil pump is started to pre-
lubricate the bearings and to supply pressure to move the slide valve and Vi slide
stop during the starting sequence. The pump remains running until the compressor
is stopped.
The type of oil pump being utilized is configured in the micro processor using Dip
Switches on the main board. Switch bank SW3, switches 1 and 2, are used to
select the configuration as described below:
The Oil Pump must be configured using the dip switches that match the installed com-
pressor configuration. This configuration should only be adjusted by qualified personnel.
SW3-1 SW3-2
NOT USED OFF OFF
PRE-LUBE ON OFF
CYCLING OFF ON
FULL LUBE ON ON
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