Brochure

Monitoring Relays
69
Siemens · 2010
3UG Monitoring Relays for Electrical and Additional Measurements
Current monitoring
■ Overview
The relays monitor single-phase AC currents (rms value) and DC
currents against the set threshold value for overshoot and under-
shoot. They differ with regard to their measuring ranges and sup-
ply voltage types.
■ Function
3UG46 21/3UG46 22 monitoring relays
The 3UG46 21/3UG46 22 current monitoring relay is supplied
with an auxiliary voltage of 24 V AC/DC or 24 ... 240 V AC/DC
and performs overshoot, undershoot or window monitoring of
the current depending on how it is parameterized. The device is
equipped with a display and is parameterized using three
buttons.
The measuring range extends from 3 ... 500 mA or 0.05 ... 10 A.
The rms value of the current is measured. The threshold values
for overshoot or undershoot can be freely configured within this
range. If one of these threshold values is reached, the output re-
lay responds according to the set principle of operation as soon
as the tripping delay time I
Del
has elapsed. This time and the
ON-delay time on
Del
are adjustable from 0.1 ... 20 s.
The hysteresis is adjustable from 0.1 ... 250 mA or 0.01 ... 5 A.
The device can be operated with manual or auto RESET and on
the basis of either the open-circuit or closed-circuit principle.
Following options are available: Response of the output relay
when the supply voltage U
s
= ON is applied or not until the lower
measurement range limit of the measuring current (I >3 mA/
50 mA) is reached. One output changeover contact is available
as signaling contact.
With the closed-circuit principle selected
upon application of the supply voltage
Current overshoot
Current undershoot
Window monitoring
NSB0_01579a
11/14
A
1-A2
11/12
=0
>
Hysteresis
DelayonDelay
NSB0_01580a
= 0
11/14
A
1-A2
11/12
<
Hysteresis
DelayonDelay
NSB0_01626a
>
11/14
11/12
= 0
A
1-A2
<
Hysteresis
Hysteresis
Delay
Delay
Delay
Delay =
onDelay