LEM SATURN 100 plus Instrucciones De Uso página 47

Information for the tester
FI (RCD-) Circuit Breaker Test
The first measurement performed checks whether the voltage U
greater than 101 V and less than 253 V. The measurement is performed by means
of analogue-digital conversion (ADC). The processor then performs evaluation and
further processing.
If the above condition is met, measurement is started. The required switching
processes are performed by means of safety relays controlled by the processor.
After being switched on, the controllable current source (RCD, R
the line showing the greater voltage. There follows an alternation of load during
one cycle of the mains-voltage and no load in the following cycle. The difference of
the terminal voltages measured serves as a basis for computation of the fault
voltage and of the loop resistance.
If a probe is used, the probe voltage is measured under load, followed by
computation of the contact voltage and of the earthing/grounding resistance. Biased
currents do not result in errors in the computation of the contact voltage. In order to
determine the total fault voltage of the installation the probe voltage prior to the
triggering of the measurement must be added to the fault voltage determined during
measurement!
In order to check for non-tripping of the FI circuit breaker, the system is
subsequently loaded during 500 msec with 35% of the set nominal fault current.
When measuring the tripping time, the set nominal fault current (I∆ N ) is applied for
S
500 msec at x 1, x 2 and 150 msec at x 5, respectively, and the current flow is
S
monitored. With - FI-measurements, the double nominal fault current (2 x I ∆N ) or
the quintuple nominal fault current (5 x I ∆N ) is applied and the current flow is
monitored. If the FI-circuit breaker trips, the interruption of the current flow is
detected. The time from the start of the current flow to the tripping of the circuit
breaker (interruption of current) is measured in the processor and displayed as the
tripping time (t ). If the FI circuit breaker trips, the interruption of current flow is
A
detected. The time from the start of the current flow to the tripping of the circuit
breaker (interruption of current) is measured in the processor and displayed as the
tripping time (t ). When choosing the ramp function with increasing fault current,
A
the increase of the nominal fault current is obtained in 13 increments of each 300
ms from 35 ... 95 % and in 3 increments of each 500 ms from 100 ... 110 % of I∆N
until the FI circuit breaker trips. The time from the start of the current flow (start of
increments) until the tripping of the circuit breaker (interruption of current) is
measured in the processor and displayed as the tripping time (t
the tripping current (current of increment – IA) is displayed.
or U is
L-PE N-PE
) is connected to
A
). Simultaneously,
A
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