Kikusui TOS3200, User Manual

Page: 51 / 130

TOS3200
51
Setting Test Conditions of the TC Measurement
4
TC and
PCC T
est
s
Fig. 4-11 shows how the relays inside the TOS3200 switch depending on the settings of the
PROBE, POL, and COND items.
Fig. 4-11 Conceptual diagram of the TC measurement
Earthing check
If the PROBE is set to ENCLIV or ENCNEU, measurement terminal A is connected to the
EUT enclosure (floating section) and terminal B of the measurement network is connected to
the power line (L or N) inside the TOS3200 to execute the test. Therefore, if the EUT enclo-
sure is grounded, a dangerous earth fault will result through the NTWK. It is also possible that
measurement terminal A is connected to the grounded section of the enclosure by mistake. It
is necessary to check that the measurement point is not grounded in advance to perform the
test safely.
The earthing check automatically performs this check. When you press the START switch,
the TOS3200 supplies a low current between measurement terminals A and earth before the
actual test, measures this current, and checks the grounding of the measurement point. If the
measurement point is grounded, “
↕
FAIL” (CONTACT FAIL) will be indicated on the screen,
and the test will be aborted.
p. 94
Both the U-FAIL and L-FAIL signals are delivered from the SIGNAL I/O connector.
To clear CONTACT FAIL, press the STOP switch.
NORM
L
N
G
L
N
PE
B
B
A
A
NORM
NORM
FLT
NEU
FLT
PE
E
NC
E
NC
E
NC
P
E
E
NC
N
EU
E
NC L
IV
REVS
POL
COND
PROBE
AC LINE OUT
EUT
EUT
AC LINE IN
EUT
NTWK
TOS3200
See
CAUTION
If you connect the test lead to the measurement point after you press the START switch, the
TOS3200 will judge that the measurement point is not grounded, and the earthing check will
pass. If you do this, you cannot check mistakes in the connection. Be sure to connect the
test lead to the measurement point first, and then press the START switch.