1736/1738
Users Manual
6
Voltage Test Leads
Voltage test leads are four-core, flat, test leads that do not tangle and
can be installed in tight spaces. On installations where the access to
Neutral is out of reach with the three-phase test lead, use the black
test lead to extend the Neutral lead.
For single phase measurements use the red and black test leads.
Thin-Flexi Current Probe
The Thin-Flexi Current Probe works on the Rogowski coil (R-coil)
principle that is a toroid of wire used to measure an alternating current
through a wire encircled by the toroid. See Figure 3.
Figure 3. R-Coil Operation Principle
The R-coil has advantages over other types of current transformers:
•
It is not a closed loop. The second terminal is passed back through
the center of the toroid core (commonly a plastic or rubber tube)
and connected along the first terminal. This allows the coil to be
open-ended, flexible, and able to be wrapped around a live
conductor without disturbing it.
•
It has an air core rather than an iron core. It has a low inductance
and can respond to fast-changing currents.
•
Because it has no iron core to saturate, it is highly linear even
when subjected to large currents, such as those used in electric
power transmission or pulsed-power applications.
A correctly formed R-coil, with equally spaced windings, is largely
immune to electromagnetic interference.
Use the cable markers for easy identification of the four current
probes. Apply the markers on both ends of the current probe cable.
See Figure 4.
Figure 4. Test Leads with Cable Markers
Kensington Lock
A Kensington Security Slot (also called a K-Slot or Kensington lock) is
part of a built-in anti-theft system. It is a small, metal-reinforced, oval
hole found on the right side of the Logger (see item 6 in Table 3). It is
used for attaching a lock-and-cable apparatus. The lock is secured in
place with a key or combination lock attached to a plastic-cover metal
cable. The end of the cable has a small loop that allows the cable to
be looped around a permanent object, such as a cabinet door, to
secure it in place. This lock is available from most electronics and
computer suppliers.
i(t)
v(t)
A
r
10 k R3
330 k R1
10 nF C1
LF347
UI:A
1
GND
2
114
3
V
in
V
out
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