Functions - Siemens 3UG4 User Manual

9.3.2

Functions

General functionality
The 3UG4581 insulation monitoring relays are supplied with a rated control and supply
voltage of 24 V to 240 V AC/DC, and they monitor the insulation resistance in ungrounded
AC systems in accordance with IEC 61557-8.
The devices can monitor control circuits (1-phase) and main circuits (3-phase). For this
purpose, the insulation resistance between the system cables (terminal L) and system
ground (terminal
AC (50 to 60 Hz) can be connected directly to the measuring inputs, and their insulation
resistance can be monitored.
The 3UG4581 insulation monitoring relays have two rotary buttons for adjusting the
insulation resistance R and a test/RESET button for performing an internal test on the
device, or for resetting the device.
If the measured value drops below the set threshold, the output relays are set to fault status.
For systems with voltages over 400 V AC, the 3UG4583 insulation monitoring relays with
3UG4983 upstream module can be used for system voltages to 690 V AC.
You will find the setting ranges and factory settings of the available parameters in Chapter
"Operator control (Page 224)".
You will find a description of the individual parameters in the Chapter "Parameters
(Page 363)".
Measuring procedure of the 3UG4581 insulation monitoring relay
An overlaid DC measuring signal is used on the 3UG4581 insulation monitoring relay for
measuring. The insulation resistance of the system is calculated with the help of the overlaid
DC measuring voltage and the resulting current.
The 3UG4581 insulation monitoring relays can be configured to the relevant application
conditions and are therefore versatile in use.
3UG4 / 3RR2 monitoring relays
Manual, 05/2016, NEB927043002000/RS-AC/004
) is measured. Systems with rated system voltages U
3UG458. insulation monitoring relay
9.3 3UG4581 insulation monitoring relay
= 0 to 400 V
n
219