96 Capacity controller RS8GN202 © Danfoss 11-2013 AK-PC 783
Capacity distribution methods
The capacity distributor can work based on 2 distribution
principles.
Coupling pattern – Cyclical operation:
This principle is used if all compressors are of the same type and
size. (though not speed-controlled).
The compressor cuts-in and cuts-out in accordance with the "First
In First Out" principle (FIFO) to equalise operating hours between
the compressors.
Speed-regulated compressors will always be cut in rst, and the
variable capacity is used to ll capacity gaps between the subse-
quent steps.
Timer restrictions and safety cut outs
If a compressor is prevented from starting because it is “hanging”
on the restart timer or is safety cut out, this step is replaced by
another compressor.
Operating time equalisation
The operating hour equalizing is carried out between compressors
of the same type with the same total capacity.
-At the dierent startups the compressor with the lowest number
of operating hours will be started rst.
- At the dierent stops the compressor with the highest number of
operating hours will be stopped rst.
- For compressors with several steps, the operating time equalizing
is carried out between the compressors’ main steps.
Coupling pattern – Best t operation
This principle is used if the compressors are of dierent sizes.
The capacity distributor will cut-in or cut-out the compressor
capacity in order to ensure the least possible capacity jump.
Speed-regulated compressors will always be cut in rst, and the
variable capacity will be used to ll capacity gaps between the
subsequent steps.
Timer restrictions and safety cut outs
If a compressor is prevented from starting because it is “hanging”
on the restart timer or is safety-cut out, this step is replaced by
another compressor or another combination.