Checking Of Differential Device - Chauvin Arnoux C.A 6710 Notice De Fonctionnement

5. CHECKING OF DIFFERENTIAL DEVICE

A
The differential devices can be checked using the following instruments:
- C.A 6115N
- MX 4600
- CDA 10
The CDA 10 is a tester: it uses LEDs to indicate whether the differential device is operating correctly according to the calibre
selected.
It does not allow the following measurements.
Measurements possible with the C.A 6115N and MX 4600:
Differential trigger time
Measurement of the fault voltage/contact voltage
Testing of a selective differential
Testing of an AC-type differential (sensitive to AC currents) or type A differential (sensitive to pulsed AC and DC currents)
Creation of a leakage current between 4 and 34 mA
MEASUREMENT:
Set to the TT or TN neutral system (see § 3.1 and 3.2) .
The two differential devices RDD1 and RDD2 must be set to I.
Connect to socket PR1 or PR2.
- if C.A 6115N: use the cable ending in a mains plug to directly connect to the PR1 or PR2 socket.
- if MX 4600: also use the cable ending in a mains plug to directly connect to the PR1 or PR2 socket.
Activate measurement.
The recent measuring instruments enable the differential devices to be discharged before the start of the test (wait for 30
seconds) if they are selective.
They also allow you to choose the starting slope (positive or negative) of the test wave. The differential devices may react
differently in these two cases if they were polarized beforehand by leakage currents.
It is possible to vary the earth resistance or PE conductor resistance during the test, which will change the fault voltage
measured by the measuring instruments.
If you do not want to pass through the earth resistances, simply connect the A terminals.
Reminder:
Fault voltage = voltage which occurs on the earth when the nominal current of the differential device circulates.
Fault tension = R x In. It must be < 50 V or 25 V (dry or humid conditions).
earth
If the G terminals are connected by means of a lead, it is possible to:
- Measure the leakage current created by the potentiometer P using an ammeter or a leakage current clamp, for example.
- Modify the loop for circulation of this leakage current:
- Without doing anything = phase-neutral
- By pressing the pushbutton located on socket PR2 = phase-earth
DDR1
Figure 4
no triggering
triggering
21
DDR2
PR1
P
PR2
G