LT-S-(L) Technical manual
3
）
Compressor unloading for startup, and stop
To decrease the mechanical loading to compressor’s parts and
decrease the starting
current during start up. Hanbell designs for LT compressor the function of unloading
startup. To ensure compressor loads steadily, please follow Figure 3-16 to load step by
step during the whole loading process.
When compressor is about to shut down, it is also required to unload to ensure that
the slide valve is at lowest loading position during next startup and compressor could
have an unloading startup. Thus Hanbell requires no matter what load condition of the
compressor is, it should be unloaded step by step till minimum load before stop
according to below Figure 3-16.
Figure 3-16. Compressor Startup and Stop Process
Caution
：
1
）
After startup, keep the minimum load for 10 seconds. Before shut down, keep the
minimum load for 30 seconds(Time can be set to 10~60seconds).
2
）
After startup, when the pressure difference between high pressure and middle
pressure is less than 3.5bar, the compressor shall be run at 10% load at low
pressure stage. Don't load and open ECO.
3
）
t=30 seconds(Time can be set to 30~60seconds).
4
）
After the compressor shut down, the SV1 (unload) & SV2(10%) need to be still
energized for 3 minutes, so as to ensure the compressor can still at min load
position at next startup.
5
）
Hanbell strongly recommends that the compressor start-up and shutdown control
logic shall refer to above graph. For detail information
please refer to the regulations written in LT-S Control Requirements.
