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to protect (see example on TAB 1).
In normal functioning conditions there is only a red-light signal (READY), the
relays are all excited.
In pre alarm conditions there is a yellow light signal (PRE-ALARM), the relay K2
is turned off.
In alarm conditions all the luminous signals are active, only K1 relay is excited.
In case of breakdown and obviously of back off supplying, there is no luminous
signal, all the relays are turned off, the FAULT signal appears on terminal n. 1
(only if the input signal to terminal n. 2 is present).
Attention: the FAULT device signal (terminal n.1) is turned on when the control
device is in broken state or not supplied, but it is active also during the lightly
phase for about 2 seconds (that is the K1 lighting delay).
In normal conditions, the relays are always exited, in case of breakdown of the
sensors or in case of exceeding of the temperature limits, the relays turn off.
The interconnections among the relays contacts are shown on TAB 1.
The pre alarm relay, with proper values of the PTC probes (50÷60 °C) can also
be used to manage the transformer fan cooling.
Level for alarm and pre alarm relays (2.6 ÷ 3.0 K ohm).
Level of recommutation for alarm and pre alarm relays (1.5 ÷ 2.0 K ohm)
MODALITY OF THE INTERVENTIONS
When one of the thermometric probes detects an increased temperature in the
range of the release point (incertainty of about 5 °C), you have the switching off
the relay and the luminous signal on the frontal panel.
As soon as the temperature values go down some grades below the previous
intervention point, the relays switch on again and the luminous signal
disappears.
THERMOMETRICAL PROBES DIAGNOSTIC
The temperature control is indicated as follows:
in case of disconnected probe or temperature beyond the release point,
switching off the relative relay and active the relative luminous signal.
