LEM SATURN 100 plus Instrucciones De Uso página 27

Measuring
3.7.1 Testing Plants of Max. Contact Voltage 25 V
For measurements in plants where the maximum permissible contact voltage
is 25 V, always begin with a measurement without tripping at I = 10 mA.
∆ ∆ ∆ ∆ N
With this measurement only 35% of the nominal fault current (3.5 mA) is applied for
a maximum of 500 ms causing only half the contact voltage to be present; however,
the values will be computed to the full test current, which provides for the safe
determination of „U L " . If the contact voltage shown is below 25 V, the
measurement must be repeated with the next higher nominal fault current
until the nominal fault current of the installed FI-circuit breaker has been
reached. If the contact voltage is still below 25 V, the measurement must be
redone with the tripping option.
NOTE ON THE MEASURING SEQUENCE:
k
When testing fault-current circuit breakers, pressing key „Start" starts
measurement in 3 phases.
Phase 1
In this phase the measured values of the contact voltage „U " and of the loop
L
resistance „R " - or, for measurement with probe, the earth/ground-connection
S
resistance „R " - are obtained. The measurement is effected at 35% of the set
A
nominal fault current over several full sine waves mutually separated by a pause of
one cycle each. All measured values are subsequently recomputed for the full
nominal fault current and stored. Simultaneously a check is performed whether the
contact voltage at full nominal fault current exceeds 50 V. If this is the case, the test
sequence is aborted after phase 2, and the measured values are displayed with a
message indicating excessive contact voltage. If the contact voltage exceeds 99 V,
the measurement is already aborted after phase 1, and the excess is reported.
This is where, in FI-circuit-breaker tests „without tripping", measurement is aborted
and the measured values are displayed.
Note:
If the FI circuit breaker trips during phase 1, no measured values can be obtained,
and
„U--- V" or „R --- W" or „t --- ms" is displayed.
S A
25