Setup Control Of Condenser Fans - Danfoss AK-PC 781A User Manual

Configuration - continued
Setup control of condenser
fans
1. Go to Configuration menu
2. Select Condenser fan control
3. Set control mode and reference
Press the +-button to go on to the
next page
4. Set values for capacity regulation
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In our example the condenser
pressure is controlled on the basis
of the Sgc and from Sc3 (floating
reference).
The settings shown here in the
display.
In our example we use a number of
fans that are all speed-controlled
in parallel.
The settings shown here in the
display.
For your information the function
"Monitor fan safety" will require
an input signal from each fan.
Capacity controller RS8HE202 © Danfoss 2017-07
3 - PC reference
Control sensor
Pc: The condensing pressure PC is used for regulation
Sgc: The temperature at the outlet of the gas cooler (CO2
transcritical only)
S7: Media temperature is used for regulation
Reference Mode
Choice of condenser pressure reference
Fixed setting: Used if a permanent reference is required =
"Setting"
Floating: Used if the reference is changed as a function
of Sc3 the external temperature signal, the configured
"Dimensioning tm K"/"Minimum tm K" and the actual cut in
compressor capacity. (Liquid is recommended for CO2 and
heat recovery.)
Setpoint
Setting of desired condensing pressure in bar
Min. tm
Minimum average temperature difference between Sc3 air
and Pc condensing temperature with no load.
Dimensioning tm
Dimensioning average temperature differential between Sc3
air and Pc condensing temperature at maximum load (tm
difference at max load, typically 8-15 K).
Min reference
Min. permitted condenser pressure reference
Max reference
Max. permitted condenser pressure reference
4 - Capacity control
Capacity control mode
Select control mode for condenser
Step: Fans are step-connected via relay outputs
Step/speed: The fan capacity is controlled via a combination
of speed control and step coupling
Speed: The fan capacity is controlled via speed control
(frequency converter)
Speed 1.step: First fan speed controlled, rest step coupling
No of fans
Set number of fans.
Monitoring fan safety
Safety monitoring of fans. A digital input is used to monitor
each fan.
Fan speed type
VSD (and normal AC motors)
EC motor = DC controlled fan motors
VSD start speed
Minimum speed for start of speed control (Must be config-
ured higher than "VSD Min. Speed %")
VSD min Speed
Minimum speed whereby speed control is cut-out (low
load).
VSD safety monit.
Choice of safety monitoring of frequency converter. A digital
inlet is used for monitoring the frequency converter.
EC Start capacity
The regulation awaits this need to arise before supplying
voltage to the EC motor
EC voltage min
Voltage value at 0% capacity (20% = 2V @ 0-10V)
EC voltage max
Voltage value at 100% capacity (80% = 8V @ 0-10V)
EC Voltage abs. max
Permissible live voltage for EC motor (overcapacity)
Absolut max Tc
Max value for Tc. If this Tc value is exceeded, the EC voltage
will be raised to the value in "EC Voltage abs. max. "
Continues
AK-PC 781A