L2275
Emax UL
70/132
Doc. N°
Mod.
RH0109002
Apparatus
Scale
Page N°
15.2.6.7
Protection against overtemperature inside the “OT” trip unit
A sensor is placed inside the PR113 unit which monitors the temperature of the unit.
This allows the presence of abnormal temperatures which could cause temporary or continuous malfunctions of the electronic components of
the unit to be signaled.
This protection has two states of operation:
$
State of “WARNING TEMPERATURE” with
–25°C < temp. < -20°C
o r
70°C < temp. < 85°C;
the display is turned off
and the “TEMP” LED flashes.
$
State of “ALARM TEMPERATURE” with
temp. < –25°C
or
temp. > 85°C;
the display is turned off,
the “TEMP” LED remains lit and the Trip is activated (if enabled, by means of the “Over Temper. Trip” = On parameter).
The precision of temperature measurement is ±1°C (“range” of measurement –40°C…+125°C).
N.B.:
%
In case of Warning and Alarm, the display is momentarily off, to preserve its functionality.
%
The monitored temperature is not visible on the display.
The protection is always active, both with auxiliary supply and in self-supply.
Disabling the Trip control of the protection means that the PR113 unit could work, with the power circuit breaker closed,
in a range of temperatures where correct operation of the electronics is not guaranteed.
15.2.6.8
“K” Load control function
There are two distinct protection curves with threshold currents and trip times lower than those selectable with protection L, which can be used
for the following two applications:
1. disconnection of two distinct loads (2 curves with inverse time t = k/I
2)
;
2. connection and disconnection of one load (curve with adjustable delay t= k for connection and with inverse time t= k/I
2
for disconnection)
These protections allow single loads to be connected/disconnected before protection L against overload intervenes to definitively open the power
circuit breaker.
The disconnection protections use trip curves similar to those used by protection “L”, but with lower thresholds and shorter times. The reference
curves are those of protection “L”.
Presence of a thermal memory is not foreseen. Operation with “L” thermal memory inserted could cause abnormal behavior.
The “Load control” protection is carried out by means of the relay contacts on board the PR113 unit (K51/p1 and K51/p2 to be configured) or by
means of the contacts supplied by the PR020/K accessory signaling unit (par. 15.7.2). The function is only active when there is an auxiliary power
supply.
The protection can be totally disabled by selecting the value [Off] beside the indication of the type of control activated (see par.15.4.2.2). Each
single protection is excludable by selecting “Off” for the threshold.
The trip thresholds are expressed in percentages of the “L” (I
1
) threshold. The trip times for load disconnection are fractions of the time selected
for protection “L” (t
1
).
15.2.6.8.1 Disconnection of two loads
The opening control for load n°1 is sent when I
max
> Ic1 (for the time curve = t1/4). At this point the protection is disabled and a message appears
for “load 1 open”.
The opening control for load n°2 is sent when I
max
> Ic2 (for the time curve = t1/2). At this point the protection is disabled and a message appears
for “load 2 open”.
To re-enable operation of the protections on load n°1 (or n°2), it is necessary to press the “RESET” key, on the current page, on the “default” page
or on the one for configuration of protection “K”.
15.2.6.8.2 Connection - Disconnection of a load
For reclosing timing with fixed adjustable time tc1 is applied. The closing control for load n°1 is sent when I
max
< Ic1 (for the time set with tc1). On
start-up of the unit, if self-reclosing is not locked, reclosing is always carried out if I
max
< Ic1.
The opening control for load n°1 is sent when I
max
> Ic1 (for the time curve = t1/2). At this point the protection is disabled and a message appears
for “load 1 open”.
It is re-enabled by the automatic reclosing or by pressing the “RESET” key on the currents page, on the “default” page or on the one for configuration
of the protection (the opening protection is released voluntarily without a reclosing operation having taken place).
When the number of self-reclosing operations reaches the maximum number of self-reclosing operations which can be carried out (“Nr. AR =
MaxAR”), reclosing is disabled (
a message appears for “self-reclosing operation disabled”
). To re-enable it, it is necessary to reset the “Nr. AR” (
by entering
the protection setting page in “edit” mode
).
15.2.6.9
Voltage protections “UV”, “OV”, “RV”
The PR113 unit carries out 3 voltage protections, which are excludable, with fixed adjustable time (t = k), active both with self-supply and with auxiliary
supply:
– Undervoltage “UV”
– Overvoltage “OV”
– Residual voltage “RV”