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pompe almeno un minuto di flusso ogni 23 ore. Questo avviene qua-
lunque sia la configurazione dell'inverter (enable o riserva). Lo scambio
di priorità prevede che l'inverter fermo da 23 ore venga portato a pri-
orità massima nell'ordine di partenza. Questo comporta che appena
si renda necessario l'erogazione di flusso sia il primo ad avviarsi. Gli
inverter configurati come riserva hanno la precedenza sugli altri.
L'algoritmo termina la sua azione quando l'inverter ha erogato almeno
un minuto di flusso. Terminato l'intervento dell'antiristagno, se l'inverter
è configurato come riserva, viene riportato a priorità minima in modo da
preservarsi dall'usura.
Riserve e numero di inverter che partecipano al pompaggio
Il sistema multi inverter legge quanti elementi sono connessi in comu-
nicazione e chiama questo numero N. In base poi ai parametri NA ed
NC decide quanti e quali inverter devono lavorare ad un certo istante.
NA rappresenta il numero di inverter che partecipano al pompaggio.
NC rappresenta il massimo numero di inverter che possono lavorare
contemporaneamente. Se in una catena ci sono NA inverter attivi e
NC inverter contemporanei con NC minore di NA significa che al mas-
simo partiranno contemporaneamente NC inverter e che questi inverter
si scambieranno tra NA elementi. Se un inverter è configurato come
preferenza di riserva, sarà messo per ultimo come ordine di partenza,
quindi se ad esempio ho 3 inverter e uno di questi configurato come
riserva, la riserva partirà per terzo elemento, se invece imposto NA=2
la riserva non partirà a meno che uno dei due attivi non vada in fault.
Introduction to multi inverter systems
A multi inverter system comprises a pump set made up of a series of
pumps with delivery outlets all conveying to a single manifold. Each
pump of the set is connected to its own inverter and the various invert-
ers communicate via a special connection (Link).
The maximum number of pump-inverter elements possible in a group
is 8.
A multi inverter system is mainly used to:
- Increase the hydraulic performance with respect to a single inverter
- Ensure operation continuity in the event of a fault on a pump or
inverter
- Partition maximum power
Setting up a multi inverter system
The pumps must all be connected to a single delivery manifold and the
flow sensor must be placed on the outlet of the latter to read the flow
to the entire pump set. In the case of using multiple flow sensors, these
must be installed on the delivery of each pump.
The pressure sensor must be connected to the outlet manifold. If more
than one pressure sensor is used, these must also be installed on the
manifold or in any event on a pipeline that is connected to it.
Note:
If multiple pressure sensors are read, take care that the pipe-
line on which they are mounted is not equipped with non-return valves
between one sensor and the next; otherwise different pressure values
may be read which lead to false average readings and incorrect set-
tings.
For optimal operation of the pressure set, the following must be the
same for each inverter-pump pair:
- type of pump and motor
- hydraulic connections
WACS si riserva il diritto di apportare modifiche senza obbligo di preavviso - WACS reserves the right to make any changes it deems fit without notice - WACS se reserva el derecho de realizar modificaciones sin la obligación de aviso previo
- rated frequency
- minimum frequency
- maximum frequency
Although this is the optimal condition, some of the above parameters
may differ.
Sensors
The sensors to be connected are the same versions used in stand-
alone versions, i.e. pressure sensor and flow sensor.
Flow sensors
The flow sensors are optionals and can be connected in two ways:
- one sensor only
- the same number of sensors as inverters
The setting is entered on parameter FI. No other types of system are
admitted.
The single flow sensor must be installed on the delivery manifold and it
must intercept the hydraulic flow of the entire booster set. The electrical
connection can be made independently on any of the inverters.
Multiple sensors are useful when a specific flow rate is required on
each pump, and enhance protection against dry running operation. To
use multiple flow sensors, parameter Fl must be set to multiple sensors
and each flow sensor must be connected to the inverter that controls
the pump delivery where the sensor is located.
Pressure sensors
The pressure sensor must be inserted on the delivery manifold. There
can be more than one pressure sensor, and in this case the pressure
reading will be the average value of all those present. To use multiple
pressure sensors, the connectors are simply inserted in the relative
inputs and no parameter needs to be set. The number of pressure
sensors installed can vary as required between one and the maximum
number of inverters present.
Multi-inverter settings
When a multi inverter system is switched on, the addresses are as-
signed automatically and, by means of an algorithm, an inverter is
nominated as the settings leader. The leader decides on the frequency
and order of start-up of each inverter in the series.
The settings mode is sequential (inverters start one at a time). When
start-up conditions are enabled, the first inverter starts, and when this
reaches maximum frequency, the next one starts, and so on. The order
of start-up is not necessarily ascending according to the machine ad-
dress, but depends on the hours of operation.
When the minimum frequency FL is used, and there is only one inverter
operative pressure surges may occur. Depending no the case, pressure
surges may be inevitable and may occur at the minimum frequency
when this value, in relation to the hydraulic load, causes a pressure
level greater than the required value. On multi inverter systems, this
problem remains limited to the first pump that is started up, as on the
subsequent pumps the situation is as follows: when the previous pump
reaches the maximum frequency, the next one starts up at the mini-
mum frequency to then reach the maximum frequency.
When the frequency of the pump at maximum is reduced (obviously
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