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Figure 11: Enclosure heater
14
A
B
Enclosure heater
The enclosure heater (MLFB part
3AX1350-8A) is an optional accessory that
mounts behind the radio tray and plugs into
the power supply isolator. It uses natural
convection to heat the enclosure, i.e., there
is no fan. It has a positive temperature
coefficient element which acts as a
thermostatic control keeping the battery
and electronic compartment above 5 °F
(-15 °C) for ambient temperatures as low as
-22 °F (-30 °C).
The heater is required for climates:
Where the temperature can fall below
-4 °F (-20 °C) or
Where the temperature will regularly fall
below 14 °F (-10 °C) or
Where condensing humidity is a
recurrent problem.
The heater is suitable for continuous
operation at 90-265 Vac.
Note that a power supply isolation unit is
required if a heater is fitted.
The heater is not suitable for fitting to a
solar powered RCU.
Item
Description
Power supply
A
isolation unit
The space heater is covered by a guard. The
Enclosure
B
surface temperature of the heater may be as much
heater
as 54 °F (30 °C) higher than the ambient air. Do
not remove the guard or touch the surface of the
heater when the heater is energized.
Function of the RCU
The RCU acts as an interface between a set
of Fusesavers on the power line and a utility
SCADA system. To do this, the RCU uses its
configuration to find and access installed
and running Fusesavers mounted on the
power pole. It communicates with the
Fusesavers using its built-in short-range
radio.
The Fusesavers are installed on each of the
phases of the power line and are organized
to work as a set to control that line. One,
two or three Fusesavers can be organized in
this way for a single-phase, two-phase or
three-phase line. A RCU provides access to
the Fusesavers on a single power line so
that if there are multiple lines at a site, then
a separate RCU is required for each line.
On start up, the RCU turns on its short-
range radio and scans for transmissions
from the Fusesavers which match its
configuration.
When it finds them, it will acquire data from
the Fusesavers and put it into its database
ready for re-transmission over a long-range
radio (or modem) back to the utility SCADA
system master station. The long-range radio
is mounted in the radio tray and is provided
with power by the RCU electronic system. A
variety of data interfaces and power
supplies are provided by the RCU (refer to
RCU principle on page 9). The exact radio,
interface, power supply and protocol used
to interface to the SCADA system may be
different for each user.
Data in the RCU database includes
information about the Fusesavers and the
RCU itself. Usually a subset of this data is
mapped into the protocol used by the
SCADA system.
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