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Page 40
GUARDIAN SCC-40
Issue (Auto VI) & V3.6t 07/12/00
to balance its slide capacity with. To do this it selects the compressor with the
greatest runtime hours, from the compressors that are at Maximum capacity.
The Master then sets the Load sharing status flag of the required compressor.
This compressor then goes into slide position regulation mode, selecting a slide
capacity setpoint that divides the available capacity between the Master and
itself. The load sharing compressor moves to its calculated slide position,
from 100%, by pulsing its lower valve. The Master compressor remains in
suction pressure regulation mode, so as the pressure goes above the control
band it will increase its capacity. The load sharing compressor continues to
adjust its slide position setpoint as required.
The following situations may now occur:-
i)
The refrigeration demand increases:-
Both compressors reach Maximum capacity and maintain this for the stage up
period of the Master. The Master then removes the load sharing status, updates
this status change to all other controllers and then stops transmitting so that the
compressor with the next highest priority will take over.
ii)
The refrigeration demand decreases:-
In this situation the load sharing compressor will not allow its slide to go below
50%. The Master compressor will compensate by continuing to reduce its
capacity. When the total load of the 2 compressors is <100% for the stage down
period then the load-sharing compressor will remove its load sharing status,
ramp its slide down to minimum and then stop.
The master compressor will maintain suction pressure regulation.
iii)
Master compressor trips.
If the load sharing compressor is not fully loaded it will be given highest priority,
revert to suction pressure regulation mode and become Master.
iv)
Load sharing compressor trips.
The Master compressor maintains suction pressure regulation and if the
previously stated conditions occur it will look for another compressor to load
share with.
Any mode changes made to the Master or load sharing compressor then
the response is the same as for a trip condition.
STOPPING
The compressor may be stopped at any time by pressing the stop button.
This will cause the compressor to unload to minimum and then stop.
The controller will then display the MANUAL OFF mode.
Содержание SCC 25
Страница 12: ...Page 12 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 Consultant Format SCC40 Std ...
Страница 51: ...Page 51 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 Auto VI Drawing ...
Страница 52: ...Page 52 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 Auto VI Wallbox Wiring ...
Страница 73: ...Page 73 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 SCC 40 Enclosure wiring for trips negative ...
Страница 74: ...Page 74 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 SCC 40 Enclosure wiring for trips positive ...
Страница 76: ...Page 76 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 Standard Wallbox Internal wiring ...
Страница 77: ...Page 77 GUARDIAN SCC 40 Issue Auto VI V3 6t 07 12 00 Standard SCC 40 Drawing ...