Bender NGRM700 User Manual

Initial commissioning
58
NGRM7xx_D00292_07_M_XXEN/02.2022
Resistance trip threshold (R
NGR
)
HRG
Both trip thresholds for the resistance are set as a percentage of the nominal NGR. Set-
ting range of trip threshold R
NGR
10…90 % (factory setting 50 %)
110…200 % (factory setting 200 %).
LRG
The upper trip threshold for the resistance is set in .
Setting range trip threshold R
NGR
200…500  (factory setting 250 )
In the case of the passive measurement method the resistance R
NGR
is determined us-
ing the current and voltage measurements. Accuracy depends on the measuring cur-
rent transformer.
In the case of the active measurement method the device generates an active test
pulse and measures R
NGR
even if the installation is de-energized.
8.2 Output relays operating modes
The factory setting for the relays is fail-safe. In the case of a device test, the relays change
state. The settings can be changed in menu 6.6.1…6.6.6 (see page 49).
8.2.1 Field calibration
After the parameters have been entered, a field calibration must be carried out. During
this process, the set resistance value of the NGR calibrates to the measurement equip-
ment of the NGRM.
For the field calibration, the device must be in auto mode (menu 6.3.1 = auto).
If calibration is not possible (e.g. due to incorrect settings) an error message appears
(6.10).
8.2.2 Trip times
The three relays have different trip times:
 Ground-fault relay 40 ms, not configurable
 NGR relay 7.5 s, not configurable
 Trip relay 100 ms…48 h, configurable for ground faults
(depends on the CD-NGRM used)
0…48 h, configurable for NGR faults
Start field calibration in the
Main menu > 6.7 Field calibration.

Bender NGRM700 Specifications

General

Brand	Bender
Model	NGRM700
Category	Measuring Instruments
Language	English