CS 2099 Eurocheck
Eurocheck operation
20
4.12 Voltage and frequency calibration
Eurocheck offers a.c. voltage source of 50 V (at 240 V mains voltage). This source can
be used for voltage and frequency calibration. It is possible (and recommended) to
include second value into your calibration procedure – 0 V (short-circuited test leads,
not open). Frequency is equal to mains and is usually very close to 50 Hz or 60 Hz.
Most Metrel installation test instruments measure all three line voltages: U
L-N
, U
L-PE
and
U
N-PE
. Newer models offer special function where all three voltages can be monitored at
the same time. Older models require that separate measurements of all three voltages
are performed in different functions (like R
LINE
– U
L-N
, R
LOOP
– U
L-PE
and R
N-PE
– U
N-PE
).
In some models it is possible to use phase rotation function to measure all voltages at
the same time. Refer to the User manual of your instrument for more information.
However, only one voltage can be calibrated at a time, since Eurocheck offers only 2-
lead connection. Leave the unused lead disconnected.
Voltage and frequency measurement calibration can be performed with universal test
cable or tip commander. Only universal test cable makes possible calibration of all 3 line
voltages. Make sure to follow connection instructions for the tested instrument. Generic
connection diagram is shown in Figure 4.5.
Step
Action
1
q
Connect tested instrument into Eurocheck voltage test sockets using
universal test cable, follow connection diagram shown in Figure 4.5; start
with L and N leads (U
L-N
calibration).
2
q
Switch on the tested instrument and select appropriate voltage
measurement function.
q
Start voltage measurement manually if necessary.
3
q
Connect Eurocheck into mains wall socket and enable its output.
q
Observe any warnings displayed on the tested instrument and
Eurocheck.
q
If Eurocheck signals incorrect L and N polarity, reverse connection.
4
q
Perform voltage and frequency measurement with the tested instrument.
q
Write down measurement result for documentation purposes.
5
q
If measured voltage or frequency deviates significantly from reference
values, it is very likely the tested instrument is damaged. Send it to your
distributor or manufacturer for repair and/or readjustment.
6
q
Connect another pair of measurement leads to voltage source (L and
PE, N and PE) and repeat steps 4 -5.
Notes:
q
Stability of reference voltage depends on mains voltage fluctuations. Use stabile
reference a.c. source with 240 V output if better accuracy is necessary.
Alternatively measure reference voltage with universal DMM simultaneously
(accuracy class 1 % or better).
q
Calibration value represents safe a.c. voltage limit as defined in European LVD
directive and is often used as a safe contact voltage limit when testing RCDs.
q
When calibrating 3-voltage measurement system unused voltmeters may show
irregular results (this is hardware dependent and presents no problem).
q
When using 230 V source the reference voltage is 47.9 V.