69
6.2.11. CURRENT MEASUREMENT
Particular reference conditions:
Peak factor = 1,414
DC component< 0.1 %.
Frequency: 15.8 450 Hz.
For the measurement of I
SEL
, the intrinsic uncertainty is increased by 5%.
Characteristics with the MN77 clamp:
Transformation ratio: 1000 / 1
Measurement range
5.0 - 399.9 mA
0.400 - 3.999 A
4.00 - 19.99 A
Resolution
0.1 mA
1 mA
10 mA
Intrinsic uncertainty
± (2% + 5 ct)
± (1.5% + 2 ct)
± (1.2% + 2 ct)
When a voltage is connected between the L and PE terminals, the device synchronizes to the frequency of this voltage, allowing
current measurements from 1 mA.
Characteristics with the C177 clamp:
Transformation ratio: 1000 / 1
Measurement range
5.0 - 399.9 mA
0.400 - 3.999 A
4.00 - 19.99 A
Resolution
0.1 mA
1 mA
10 mA
Intrinsic uncertainty
± (2% + 5 ct)
± (1.5% + 2 ct)
± (1.2% + 2 ct)
When a voltage is connected between the L and PE terminals, the device synchronizes to the frequency of this voltage, allowing
current measurements from 0.5 mA.
Characteristics with the C177A clamp:
Transformation ratio: 10 000 / 1
Measurement range
0.020 - 3.999 A
4.00 - 39.99 A
40.0 - 199.9 A
Resolution
1 mA
10 mA
100 mA
Intrinsic uncertainty
± (1.5% + 2 ct)
± (1% + 2 ct)
± (1.2% + 2 ct)
When a voltage is connected between the L and PE terminals, the device synchronizes to the frequency of this voltage, allowing
current measurements from 5 mA.
6.2.12. DIRECTION OF PHASE ROTATION
Particular reference conditions:
Three-phase network.
Voltage of the installation: 20 to 500 V.
Frequency: 15.8 to 17. 5 Hz and 45 to 65 Hz.
Acceptable level of amplitude unbalance: 20%.
Acceptable level of phase unbalance: 10%.
Acceptable level of harmonics (voltage): 10%.
Characteristics:
The phase order is «positive» if rotation L1-L2-L3 is anticlockwise.
The phase order is «negative» if rotation L1-L2-L3 is clockwise.
The three voltages are measured (see the characteristics in §6.2.1) and indicated as U
12
, U
23
and U
31
.
