Carel Hecu CO2 - Compressor Control

25
ENG
Hecu CO
2
+0300085EN rel. 2.2 - 07.05.2019
After compressor start-up, a delay can be set on screen Caf32 for closing
the selected equalisation valves.
For the LT confi guration, LT compressor equalisation can only be
managed using the bypass solenoid valve.
DSH control
Hecu CO2 controls superheat on the compressor discharge line at the
same time as superheat on the suction line.
If suction superheat is less than 0K and discharge superheat is less than
10K, a countdown starts to set off the corresponding alarm (DSH Low
Liquid Flowback).
The alarm activation delay can be set on screen Cae41 and can be
diff erentiated for diff erent stages of operation: compressor start-up,
steady operation, defrost/washing active.
Vacuum function:
A manual procedure is available to evacuate the system; to do this, follow
the steps described in the Manual Management Branch (Bbdxx).
During this procedure, the compressor crankcase can be preheated
(see the crankcase heating function), however at the end the initial
confi guration needs to be reset, on screen Bbd03 or Cag43.
Compressor crankcase heater:
Crankcase heating for BLDC compressors is required when the system is
being evacuated and oil lubrication is reduced due the presence of water
droplets, or when the compressor is off at low outside temperatures.
This function can be activated even without using an external heater,
but rather exploiting a special function implemented in the inverter that
controls the compressor.
The function is selected on the following screens:
Screen Cag44 is used to deactivate the function based on the outside/
ambient temperature; if "COMP OFF" mode is selected on screen Cag43.
For Toshiba compressors, the recommended values to be set for
the Crankcase current (Cag43) must be between the minimum and
maximum values shown in the following table:
Compressor
model
Crankcase set
% (min)*
Winding heat
3PH [W]
Crankcase set
% (max)*
Winding heat
3PH [W]
Toshiba DY30 39 15 74 55
Toshiba DY45 39 15 74 55
Toshiba DY67 35 13 67 47
Toshiba RY100 24 15 46 55
Tab. 6.c
(*) The crankcase current percentage value and the three-phase heat
generated in the motor windings (minimum and maximum) are
calculated at an ambient temperature of 25°C.
The current value to be applied can be adjusted depending on the
outside temperature, considering that it is not possible to exceed a
temperature of 55°C in the rotor windings when the unit is off .
6.3 Compressor control
Control can be proportional or proportional + integral (P, P+I). The
corresponding parameters are found under Compressors Æ Control Æ
screen Cab14.
The set point is in the centre of the band. Proportional control is illustrated
in the following fi gure:
Regulation request
100%
Setpoint
Regulation
probe value
Dierenziale
Fig. 6.f