ICAR CRA BS7 Instrucciones De Uso página 43

At the next power on, the configuration is automatically restored in sequence.
If a step has been disabled though the SET UP , it cannot be activated in manual mode.
Automatic mode: AUTO
The desired power factor is entered by operator.
The unit, according to the control logic, connects or disconnects the amount of capacitor
steps needed to obtain the set point.
The control is optimized by the microprocessor that decides which steps have to be
connected/disconnected and when, according to the configuration of the capacitor steps
and to the various set values.
Note:
If the auxiliary supply lacks during the automatic operation, all the steps are disconnected.
at the next power on, the unit starts working in automatic mode.
11. Signalling of under and overcompensation
When the "IND" or "CAP" LEDs next to the l cosϕ display flash, they indicate a state of
under and over compensation respectively.
Undercompensation ("IND" LED flashing and "CAP" off) occurs when the system's cosϕ
is lower than the one set and the capacitor banks are all on.
Overcompensation ("CAP" LED flashing and "IND" off ) occurs when the system's cos ϕ is
higher than the one set and the capacitor banks are all off.
If specified during set up, an alarm relay is triggered when under and over compensation
occur.
Once a given cos ϕ is set, the CRA-BS7/BS14 calculates the necessary reactive power to
achieve it. The control algorithm always minimises the shift from the system's "operating
point" from the set point. For this reason it is possible that no bank or capacitor is turned
on or off despite the calculated cosϕ.being different from the set cosϕ.
It may in fact occur that any turning on or off of the smallest capacitor bank takes the
system's "operating point" further away from the set point. That would lead to a general
worsening of the power factor and unstable behaviour that must, in all circumstances be
avoided.
12. Selective manual step command
In addition to the usual manual step command function a function that permits the manual
enabling or disabling of a specific step.
In manual mode, when "AUTO/MAN" button is pressed twice in quick succession, the first
step led flashes and, at the same time, the display shows the state of the step itself with
wording "ON" or "OFF". If, for three seconds, no button is pushed, the measurement of
the cos ϕ previously shown appears on the display.
To see the state of the step again, press the "MODE" button.
When the display shows the state of the step, by pressing the "MODE" key again, the
flashing of the led moves rightwards showing the step the command is to be carried out
on.
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