The Satellite Review Magazine The Satellite Review Magazine Vol 1 | Page 32

Electric Power and
Control Delivery Systems
for Automated Material
Handling Equipment
By Rod Griffith,

Director of Marketing, Conductix Wampfler

Intralogistic systems play an important
role in the automated transport of
materials in factories, distribution
centers, parcel services, warehouses,
airports, hospitals, and others. These
systems increase the efficiency, quality,
sustainability, and traceability of
material flow processes, while reducing
waste and inventory buffers. Without
them, modern, high-performance
facilities could not function.
Much of the available intralogistics
equipment - AS/RS, S/RMs, sorters,
stacker cranes, shut tle systems, and
monorail systems - need components
designed to deliver electric power and
control signals to the moving parts of
the system. These machines might
move horizontally, vertically, and/or
perpendicular to the storage or work
areas. Some systems must meet
special challenges, such as “clean room”
and food processing environments,
refrigerated storage, or production lines
that might produce an assortment of
contaminants. Newer machine designs
might also include energy regeneration
capabilities.
The electric power transfer is ordinarily
handled by a “conductor rail” system
as a first choice. These consist of
electrified, insulated rails (one per pole
or “wire”) mounted adjacent to the
movement path of the machine. The
moving part(s) of the machine include
a set of sliding “collector assemblies”
mounted to the machine adjacent to the
rails. The collector slides along the live
rails to pick up the power and transfer it
to the moving parts of the machine.

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The safety and reliability of the
conductor rail system is critical. Rails
should be insulated to the “finger safe”
(IP2) level. Given that many handling
machines run at high speeds and constant duty cycles, the rail system must
operate flawlessly to avoid significant
and costly machine downtime, which
could shut down an entire facility.
Providing constant power in this
manner avoids the need for on board
power generation systems or battery
operated systems that must be
recharged.
The space needed for the conductor rail
system, i.e. the “operating envelope”,
is a function of the required electrical
capacity of the rail (in amperes), the
operating voltage, and the number of
“poles” (wires) involved. Knowledgeable
and experienced electrification suppliers
offer designs that are flexible enough to
handle electrical requirements, yet fit
into a limited space. By using a variety
of conductive materials, the same rail
profile can carry low currents, say 12A
or less, or carry higher currents up to
400A.
Some electrification suppliers offer
special metal channels that form a
“shell” to accommodate several
individual conductor rails in a single
package. The use of a metal
containment shell simplifies installation,
increases the rigidity of the system, and
reduces the number of supports needed
to mount the package. In many cases
the contained conductor rail assembly
can be mounted directly to the rack
system uprights, since the shell can
withstand an unsupported span that
equals the distance between the
uprights. The shell system also provides
a convenient place for bar codes and
other types of position markers.
For some types of moving machinery,
conductor rails might not be the
preferred solution. For example, short

vertical or horizontal runs for some
machinery might be best handled with
“cable chain” – which guides and
protects special flexible cables. The
best option for Automated Guided
Vehicles (AGVs) or skillets that run at
floor level is something other than live
rails. For these AGV applications, two
different approaches can be used. First,
the AGVs might run on battery power,
which requires some type of off-line
charging station system. Second, the
AGV could be powered and controlled
by means of “inductive power transfer”.
These systems are referred to as “battery
-less AGVs”. The IPT system is a very
flexible way to connect a moving
electric machine to a constant power
grid. The system features a special
conductor mounted just under the floor
and an inductive power pickup on the
moving machine. This contact-less type
of system has no wearing parts and
allows the AGV to stay in service by
eliminating the need to recharge
batteries. The initial investment in such
a system can be significant, but cost
effective over the life of the installation.
There are seven basic factors that should
be considered when selecting the
correct power delivery system for
moving intralogistics machinery:
• Environmental conditions, such as
temperature range, and contaminants
• Duty cycles
• Mounting consideration, such as
available space, and connection
options
• Number and capacity of conductors
• Current capacity and voltages
• Voltage drop that might occur in
longer runs
• Data transfer needs and the protocols
involved
In summary, it is recommended that
the system integrator carefully review
the equipment and application with an
experienced electrification supplier.

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