Eaton PXR10 - 4 Protection Settings; 4.1 Overload Release

3 Protection and measurement functions
3.3 Measuring functions
PXR Electronic trip unit 01/21 MN012005EN www.eaton.com 21
3.3 Measuring functions
An NZM circuit breaker with PXR trip unit can be used to measure the
following values – the scope of the available measurement functions
depends on the specific PXR version.
Table 11: Measurement functions of the different PXR versions
Table 12: Current and voltage measurements
The current and voltage data are recorded at a frequency of 3,600 Hz.
The values recorded by the measurement functions are calculated at a
frequency of 1 Hz. The delay time for internal transmission of these data is
approximately 250 ms in the case of Modbus, and up to several seconds in
the case CAM communications. Data are transmitted during the specific
time periods. CAM transmission intervals of several seconds will cause the
loss of real-time data packets, depending on the CAM type. Power data
(current, voltage, power) take the form of cumulative data and are thus not
affected.
If the internal Modbus RTU is used, no recorded “intermediate data” is lost.
Function (value to be measured) PXR10 PXR20 PXR25
Current ✓ ✓ ✓
Voltage – – ✓
Power
– – ✓
Energy – – ✓
Others (e. g. cos ϕ) – – ✓
Measurement
1)
Unit of
measure
Note
Current measurement
2)
IL1, IL2, IL3, IN, IG A
Minimum IL1, IL2, IL3, IN, IG A Group values are held until reset
Maximum IL1, IL2, IL3, IN, IG A Group values are held until reset
Voltage measurement
VL1-L2, VL2-L3, VL3-L1 V Voltage phase – phase
Minimum VL1-L2, VL2-L3, VL3-L1 V Group values are held until reset
Maximum VL1-L2, VL2-L3, VL3-L1 V Group values are held until reset
VL1-N, VL2-N, VL3-N V Voltage phase – neutral
Minimum VL1-N, VL2-N, VL3-N V Group values are held until reset
Maximum VL1-N, VL2-N, VL3-N
V Group values are held until reset
1) PXR10 / PXR20: Accuracy of current measurement: 5 % valid for 40 % to 100 % of I
n
.
PXR25: Accuracy of measurement: 0.5 %
Current measurement: valid for 10 % to 120 % of I
n
at 25 °C (77 °F)
Voltage measurement: valid for 34 - 690 V AC at 25 °C (77 °F)
2) I < 0.02 * I
n
￫ I = 0 (PXR25)
I < 0.05 * I
n
￫ I = 0 (PXR10 / PXR20)