SIEMENS
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Siemens IC 10 · 2017
Relays
SIRIUS 3UG45, 3UG46 Monitoring Relays for Stand-Alone Installation
Residual Current Monitoring
Residual-current monitoring relays
10
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Overview
SIRIUS 3UG4625 monitoring relay
The 3UG4625 residual-current monitoring relays are used in
conjunction with the 3UL23 residual-current transformers for
monitoring plants in which higher residual currents are increas-
ingly expected due to ambient conditions. Monitoring encom-
passes pure AC residual currents or AC residual currents with a
pulsating DC fault current component (transformer type A in
accordance with DIN VDE 0100-530/IEC TR 60755).
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Benefits
•
Worldwide use thanks to wide voltage range from
24 to 240 V AC/DC
•
High measuring accuracy of ± 7.5 %
•
Permanent self-monitoring
•
Variable threshold values for warning and disconnection
•
Freely configurable delay times and RESET response
•
Permanent display of the actual value and fault diagnostics via
the display
•
High level of flexibility and space saving through installation
of the transformer inside or outside the control cabinet
•
Width 22.5 mm
•
All versions with removable terminals
•
All versions with screw or spring-type terminals
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Application
Monitoring of plants in which residual currents can occur,
e.g. due to dust deposits or moisture, porous cables and leads,
or capacitive residual currents.
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Technical specifications
3UG4625 monitoring relays
The main conductor, and any neutral conductor to which a load
is connected, are routed through the opening of the annular ring
core of a residual-current transformer. A secondary winding is
placed around this annular strip-wound core to which the moni-
toring relay is connected.
If operation of a plant is fault-free, the sum of the inflowing and
outward currents equals zero. No current is then induced in the
secondary winding of the residual-current transformer.
However, if an insulation fault occurs downstream of the residual
current operated circuit breaker, the sum of the inflowing cur-
rents is greater than that of the outward currents. The differential
current – i.e. the residual current – induces a secondary current
in the secondary winding of the transformer. This current is
evaluated in the monitoring relay and is used on the one hand to
display the actual residual current and on the other, to switch the
relay if the set warning or tripping threshold is overshot.
If the measured residual current exceeds the set warning value,
the associated changeover contact instantly changes the
switching state and an indication appears on the display.
If the measured residual current exceeds the set tripping value,
the set delay time begins and the associated relay symbol
flashes. On expiry of this time, the associated changeover
contact changes the switching state.
ON-delay time for motor start
To be able to start a drive when a residual current is detected,
the output relays switch to the OK state for an adjustable
ON-delay time depending on the selected open-circuit principle
or closed-circuit principle.
The changeover contacts do not react if the set threshold values
are overshot during this period.
With the closed-circuit principle selected
Residual current monitoring with Auto RESET (Memory = no)
If the device is set to Auto RESET, the relay switches back to the
OK state for the tripping value once the value falls below the set
hysteresis threshold and the display stops flashing.
The associated relay changes its switching state if the value falls
below the fixed hysteresis value of 5% of the set warning value.
Any overshoots are therefore not stored.
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> !
Hysteresis
= 0,02 A
Hysteresis = 5 %
onDelay
onDelay
Init
Delay
IC01_00225
A
1-A2
11/14
11/12
21/24
21/22
= 0
© Siemens AG 2016