62
ENG
µchiller +0300053EN rel. 2.2 - 14.12.2021
Functions
5.6 BLDC compressor protectors
To prevent the compressor from working outside the safety limits specifi ed by the manufacturer, Chiller provides controls the
operating limits (defi ned as the envelope) of BLDC compressors. In addition to the operating limits specifi ed by the manufactu-
rer, the maximum condensing temperature (par. P001) and minimum evaporation thresholds (par. P000) can be customised;
these custom thresholds are considered only if they are more restrictive than the manufacturer’s limits. On-Off compressors have
no envelope data: the operating limits can be set using the parameters for the maximum high pressure threshold equivalent
temperature (par. C017), frost protection alarm thresholds (par. U050 and S057) and MOP threshold (to control the maximum
evaporation temperature, par. E020 and E022).
Utente Cod. Descrizione Def Min Max U.M.
S P000 Min evaporation temp.: custom limit -25.0 -99.9 999.9 °C/°F
S P001 Max condensing temp.: custom limit 70.0 -99.9 999.9 °C/°F
M C017 Max high pressure threshold (HP) 65.0 0.0 999.9 °C
M C018 Min low pressure threshold (LP) 0.2 -99.9 99.9 bar
S U050 User side frost protection: alarm threshold -0.8 -99.9 999.9 °C
S S057 Source frost protection: alarm threshold -0.8 -999.9 999.9 K
M E020 MOP in cooling: threshold 30.0 -60.0 200.0 °C
M E022 MOP in heating: threshold 20.0 -60.0 200.0 °C
Di seguito la descrizione delle zone di lavoro di un inviluppo generico di un compressore BLDC:
300053_060_R01
Tc
e
1
22c
3
4
5
5c
6
7
8
9
10
Fig. 5.m
Zone Par. Description
1 Zone inside the operating limits (the prevention function is still active to prevent operation outside of the limits)
2a Maximum compression ratio 1
2b Maximum compression ratio 2
3 Maximum condensing pressure
3c P001 Custom maximum condensing pressure threshold
4 Maximum motor current
5 Maximum evaporation pressure
6 Minimum compression ratio
7 Minimum diff erential pressure
8 Minimum condensing pressure
9 Minimum evaporation pressure
9c P000 Custom minimum evaporation pressure threshold
10 High discharge temperature (but working pressure inside the envelope)
Tab. 5.h
When the compressor working point is outside of the envelope, an alarm delay starts counting: if the working point remains
outside of the envelope, when the delay expires, a specifi c alarm is activated that stops the compressor; if, on the other hand,
the working point returns back inside the envelope limits, the alarm delay is reset.
The high condensing pressure limit is determined by the minimum between:
• the nominal compressor threshold;
• the threshold modifi able by Service (par. P001).
The high evaporation pressure limit is determined by the minimum between:
• the nominal compressor threshold;
• the set MOP threshold (par. E020: chiller and E022: heat pump);
The low evaporation pressure limit for the prevention action is determined by maximum between:
• the nominal compressor threshold;
• the threshold modifi able by Service (par. P000);
• the frost protection limit, depending on the mode (par. U050 in cooling and par. S057 in heating with water/water units).
In addition to the operating limits defi ned by the shape of the envelope, there is also (heat pump versions only) a "Maximum
discharge temperature" limit (specifi ed by the compressor manufacturer), at which the compressor is shut down.
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