AMETEK ReFlex - Manual (Page 297)

Active Loads ReFlex Power™
7-22 M380056-01 Rev J
If the remote sense leads are not connected, the Active Load modules
will continue to operate but the voltage at the Source will no longer be
precisely measured. An internal resistor network exists within the
module that connects the input terminals to the remote sense
terminals. This network provides the measurement of the input
voltage when the remote sense leads are not connected. However,
since the voltage is now measured at the input terminals, the voltage
drop of the Source wiring would no longer be compensated.
Several conditions related to remote sensing are treated as faults and
result in shutdown of the output: short-circuiting of the remote sense
terminals; connecting the remote sense leads in reverse polarity;
excessive line drop in the load wires. When the fault condition is
detected, shutdown will result with the output isolation relays being
opened.
Refer to the section, User Interface, above for the Interface connector,
pinout, and wire information.
7.4.8 W
IRE
S
ELECTION
Input/output wiring must have a current carrying capacity compatible with the
current rating of the ReFlex Power™ system. The maximum current rating of
a wire is dependent on the materials used in its construction, and is primarily
limited by the insulation. The current must be limited so that the temperature
rise of the wire does not result in an operating temperature that exceeds the
rating of the wire.
W IRE C URRENT C APACITY
Table 7-4 shows maximum current ratings, based on a cable of three
conductors, that will produce an approximate 30 ºC temperature rise
above ambient. When wiring must operate in areas with an elevated
ambient temperature or bundled with other wiring, heavier gauges or
higher temperature-rated wiring should be used.
Although wire with higher temperature rated insulation will allow
operation at higher currents, the total voltage drop would also be
increased for a given wire gauge. For applications where voltage
characteristics, such as regulation, are important, it may be necessary
to size the wire based on total voltage drop instead of temperature
rise.