Seg HighTECH MRG3 - Measuring Input: Earth Current; Influences on the Earth Current Measuring

Manual MRG3 SEG Electronics GmbH
DOK-TD-MRG3, Rev. D 73
7.5 Measuring input: Earth current
Rated data: Nominal current I
N
1A or 5A
Nominal frequency f
N
50/60 Hz adjustable
Measuring range: MRG3-IE: 0 – 4.0 x I
N
MRG3-IER: 0 – 0.5 x I
N
Measuring accuracy: ±3% from measuring value or ±20mA
Power consumption in current circuit: bei I
N
= 1 A 0,2 VA
bei I
N
= 5 A 0,1 VA
Thermal withstand capability
In current circuit: dynamic current withstand
(one halfwave) 250 x I
N
for 1 s 100 x I
N
for 10 s 30 x I
N
continuously 4 x I
N
Dropout to pickup ratio: MRG3-IE 95%
MRG3-IER 97%
Returning time: 100 ms
Minimum operating time: 100 ms
7.5.1 Influences on the earth current measuring
Auxiliary voltage in the range 0.8 < U
H
/U
HN
< 1.2
no additional influences can be measured
Frequency: Only the first harmonic is evaluated. Harmonic waves are
suppressed.
Influences on delay times: no additional influences can be measured