58
Vol. 2.6 © 2020 Hanbell Precise Machinery Co., Ltd. All rights reserved
P2-P3<2.5kg/cm² warning
P2-P3
≤
2.0kg/cm² shutdown
Note
：
1. This oil pump internal resistance (R2) protection is based on the current specifications of
3/4HP oil pump (@60Hz). Please contact Hanbell technicians for other specification
configuration requirements.
2. Bearings used by RT series compressor require stable supply of lubricant.
3. Before / after compressor start-up, the start-up and shut down of oil pump must be
advanced and delayed by 3 seconds to provide sufficient lubrication.
4. Excessive lubricating oil will lead to rapid rise of bearing temperature while insufficient oil
will lead to lack of cooling and lubrication, thus the oil pump flow rate should not be
arbitrarily adjusted.
Warning
：
Only authorized and certified technicians are allowed to modify the oil pump setting.
Warning
：
Oil pump flow rate decreases as outlet pressure decreases (non-linear). Thus, do not
adjust the pump outlet pressure to deactivate the oil filter alarm (filter pressure-drop will
be smaller as oil pump outlet pressure becomes smaller) as the reduction in oil flow rate
will lead to inadequate lubrication of bearings and gears and will result in burning.
4.3 Oil cooler
The system must be equipped with external oil cooler. As built-in oil pump is used in all
models and the oil flow rate is fixed at 20~25L/min., the oil cooler should be the same for all
models (excessive oil discharged will be bypassed back into the oil tank through an internal valve).
Taking highest oil tank temperature as the temperature of oil entering the oil cooler, while the
temperature of cooled oil needs to be around 30~40
°
C and it is recommended to use refrigerant for
the cooling so that no further maintenance is required, then:
Specific gravity=Please refer to section 4.6.1
Specific heat capacity=0.45 kcal/kg°C
Oil temperature settings for the oil cooler
After the oil in the oil tank is compressed by the built-in oil pump, it enters into the oil cooler
and cooled down to a temperature between 30 and 45
°
C. Filtered by a high-density oil filter, the oil
lubricates the bearings and gear in the form of oil-jet, and finally returns to the lower pressure oil
tank. The cooling medium can either be the liquid refrigerant from the condenser or the liquid
refrigerant from the outlet motor cooling. A temperature sensor must be installed at the oil cooler
outlet to control the refrigerant flow and to maintain oil temperature of the oil cooler (Tco) between
30 ~ 40
℃
. The gaseous refrigerant in the heat exchanger can be directed back to the economizer
for reuse.
Tco>45
℃
℃
℃
℃
or Tco< 25
℃
℃
℃
℃
alarm
Tco>50
℃
℃
℃
℃
or Tco< 20
℃
℃
℃
℃
shut down
Note
：
Refer to Hanbell selection software for heat load of the oil cooler.
,
r
p
T
C
m
Q
ρ
∆
=
&
