MI 3290 Earth Analyser
Technical specifications
142
15.11 Influence of noise
Definition of noise:
Injection of series interference (voltage / current) with system frequencies of: 16 2/3 Hz, 50 Hz, 60 Hz,
400 Hz or d.c. (frequencies by IEC 61557-5).
Measurement function ........................................ 2, 3, 4 – pole, Selective (Iron, Flex Clamp),
Wenner and Schlumberger method,
HF Earth Resistance (25 kHz), Potential
Max noise interference voltage
on terminals H, S, ES and E ...................................... 40 V rms
Max noise interference current through:
Flex clamps (A1487)................................................. 30 A rms (One turn)
Iron clamp (A1018) .................................................. 5 A rms
Max external magnetic field .................................... 100 A/m (No influence)
Injected noise frequency
Test frequency
Noise rejection (* See note)
400 Hz
55 Hz … 25,0 kHz
> 80 dB
60 Hz
55 Hz
> 50 dB
82 Hz … 25,0 kHz
> 80 dB
50 Hz
55 Hz
> 50 dB
82 Hz … 25,0 kHz
> 80 dB
16 2/3 Hz
55 Hz … 25,0 kHz
> 80 dB
d.c.
55 Hz … 25,0 kHz
> 80 dB
Measurement function ........................................ 2 Clamps
Max noise interference current through:
Iron clamp (A1018) ................................................. 5 A rms (Re < 20
)
1 A rms (Re > 20
)
Max external magnetic field .................................... 100 A/m (No influence)
Notes:
Noise injection examples (voltage / current)
Rp
Rc
H
S
E
G
ES
n
oi
se
Re
Ie
C1
C2
G
F1
Re
noise
Noise icon
High electrical noise was detected during measurement. Results may be
impaired.
Limit [ Noise frequency is close
(±6 %) to the test frequency].
To high input measuring signals on terminals H, S, ES, E, Clamp, F1, F2, F2, F3 or F4.
Possible reasons: max noise interference voltage or current have been reached; check the
number of turns on flex clamps.
The measuring range of the instrument is exceeded.
Measurement could not be started or displayed!
Signal-to-noise ratio
𝑆𝑁𝑅
𝑑𝑏
= 20 ∗ log
10
(
A
SIGNAL
A
NOISE
)
