Woodward MRM4, Manual

Page: 435 / 460

Tolerances
Tolerances
It has to be observed, that the set pickup and release values (hysteresis) including tolerances, are always within
the permissible measuring range.
Real Time Clock Tolerances
Resolution: 1 ms
Tolerance: <1 minute / month (+20°C)
<±1ms if synchronized via IRIG-B
Measured Value Acquisition Tolerances
Phase and Earth Current Measuring
Frequency range: 50 Hz / 60 Hz ±10%
Accuracy: Class 0.5
Amplitude error if I < 1 x IN: ±0.5% of the rated value
Amplitude error if I > 1 x IN < 2 x IN: ±0.5% of the measured value
Amplitude error if I > 2 x IN: ±1.0% of the measured value
Resolution: 0.01 A
Harmonics up to 20% 3rd harmonic ±2%
up to 20% 5th harmonic ±2%
Frequency influence <±2%/Hz in the range of ±5 Hz of
the parametrized nominal frequency
Temperature influence <±1% within the range of -20°C up to +60°C
Protection Stages Tolerances
Note:
The tripping delay relates to the time between alarm and trip. The tolerance of the operating time relates to the
time between the measured value has exceeded the threshold until the protection stage is alarmed.
Overcurrent protection stages: I[x] Tolerance
I> ±1.5% of the setting value resp. 1% In
Resetting ratio 97% or 0.5% x In
t DEFT
±1% resp. ±10 ms
Operating time
Starting from I higher than 1.1 x I>
<35 ms
Release time <45 ms
t-char ±5% IEC NINV, IEC VINV, IEC LINV, IEC EINV, ANSI
MINV, ANSI ANSI VINV, ANSI EINV, Therm Flat, IT,
I2T, I4T
t-reset
Only available if: Characteristic = INV
±1% resp. ±10 ms
EN MRM4 01/11 Page 435