18
TOS7200
Disconnecting Test Leads from the DUT .
Connecting to an ungrounded DUT
When conducting insulation resistance testing on a DUT that has not been grounded, connect
the HIGH and LOW terminals of the tester to any two points of the DUT.
Disconnecting Test Leads from the DUT
.
1
Check that the DANGER lamp is off.
2
Remove the high voltage side test leadwire from the TOS7200 HIGH
terminal.
3
Remove the high voltage side test leadwire from the DUT.
4
Remove the low voltage side test leadwire.
You can remove either end of this test leadwire first: the DUT end or the OUTPUT
terminal end.
●
Reason that the LOW terminal of the tester is connected to the grounding terminal of
the DUT that has been grounded:
It is appropriate to connect the line terminal (LINE) to the negative (-) side of the power
source and the grounding terminal (EARTH) to the positive (+) side. When testing the
insulation of insulation wires or cables with respect to ground for direct current, connecting
the negative polarity of the power source to the core and the positive polarity to ground will
generally provide smaller measured values than when the reverse polarities are connected.
Thus, the above-noted connection is considered appropriate for the detection of insulation
failures.
For the above reason, the tester connects the negative polarity of the power source to the
HIGH terminal and the positive polarity of the power source to the LOW terminal. Thus, for
insulation resistance testing involving a DUT with one grounded terminal, it is appropriate to
connect the LOW terminal of the tester to the grounding terminal of the DUT, and the HIGH
terminal of the tester to the LIVE terminal of the DUT.
DESCRIPTION
MEMORY
VOLTAGE
RESISTANCE
TIMER
MEMORY
VOLTAGE
RESISTANCE
TIMER
OUTPUT
Ungrounded DUT
TOS7200
