Use of hybrid motor starters in conveyor belts
Significant increase in availability
Automation technology concerns itself with motion: translational and rotational. Workpieces,
semi-finished products, and tools must be moved into particular positions so that they can be
processed or used to carry out work steps. Hybrid motor starters from the Contactron product
family ensure reliable and low-wear starting and reversing conveyor belt motors at filtration
and fluid management specialist Hengst.
When the positions of machine parts and workpieces are to be changed, it is often done with
three-phase asynchronous motors. Frequency converters usually perform motion in a speedregulated manner. In a modern production unit, servo drives or robots perform many of the
precision assembly tasks. For conveyor tasks, or the movement of workpieces from one
assembly station to the next, unregulated drives are generally used. These components must
also be started, stopped, reversed, and protected from overloading.
A good example is the Hengst SE & Co.
KG fully automated final assembly (Figure
1). The company, founded in 1958 in
Münster, Westphalia, Germany, by Walter
Hengst and still owned by his family,
develops
and
manufactures
leading
filtration solutions for the global market.
Around 3,000 employees at ten national
and international sites achieved a group
turnover of 400 million euros in 2014. The
Figure 1 - The factory in Nordwalde is one of the Hengst
production sites (image: Hengst).
high-quality, multifunctional filtration and fluid management systems are used in passenger
and commercial vehicles, ship’s engines, and stationary engines. They ensure that motors,
machines, and systems work more cleanly and efficiently, use fewer resources, and improve
living conditions around the world. Hengst produces and
delivers the entire subsystem including all pressure and
die-cast elements (Figure 2).
High demands on quality
The filtration and fluid management systems have a high
level of vertical integration. “At Hengst, manufacturing
begins with an aluminum ingot or plastic granulate,” says
Figure 2 - The high-quality, multifunctional
filtration and fluid management systems are
used in passenger and commercial vehicles,
among other applications (image: Hengst).
Alfons Lehmbrock, project engineer for the company’s
proprietary
mechanical
engineering
operation,
not
without pride. This creates independence from external
suppliers and a high degree of flexibility. It also allows Hengst to retain control of the quality
of the manufactured products and therefore live up to its own high standards. As Alfons
Lehmbrock’s job description implies, self-manufactured production systems including the
associated software and electronics design are planned, designed, and constructed by the
company itself (Figure 3). In this way, the filtration and fluid management specialist ensures
that the production facilities meet the company’s special requirements and maintain high
availability, and that maintenance of the systems is optimised to meet the company’s own
needs.
Hengst has come to offer services in the
area of mechanical engineering to other
companies as well, even those outside
the automotive industry. The extensive
know-how of company technicians is
thus made available to external partners
as well. The forward-looking Industry 4.0
project, which is receiving a great deal of
attention, concerns Hengst, too. “But
Figure 3 - The production systems and associated electronics design
are planned, designed, and installed by Hengst’s own mechanical
engineering operation.
while most companies are still talking
about Industry 4.0, we are already
implementing the initial concepts in our
own production,” Alfons Lehmbrock says. “Our activities include such aspects as traceability
in manufacturing and the combination of one-of-a-kind semi-finished products to form a
complete product in which the individual parts fit perfectly.”
Significantly more space in the control cabinets
Whether they are intended for use at Hengst or to be delivered as high-quality machines, the
devices exhibit quality, user-friendliness,
and component longevity upon which great
importance
is
placed.
This
makes
it
noteworthy that, for the operation of the
conveyor belts installed in the high-quality
assembly systems, Hengst uses hybrid
motor starters from Phoenix Contact’s
Contactron product range (Figure 4). The
devices start and reverse the three-phase
asynchronous motors installed there in a
reliable, low-wear manner. Their integrated
Figure 4 - For the operation of the conveyor belts installed in the
assembly systems, Hengst uses hybrid motor starters from the
Contactron product family.
overloading function also protects motors
from blockages. Like conventional motor protection relays, the hybrid motor starters also
report faults that have occurred. If necessary, they shut down the drive safely according to
the Machinery Directive. During the process, Performance Level PL e according to DIN EN
ISO 13849-1 or Safety Integrity Level SIL 3 according to EN 62061 is achieved. This means
that the hybrid motor starters combine four functions within a design width of 22.5 mm A
comparable conventional construction would consist of two contactors for clockwise and
counter-clockwise
motion,
two
redundant emergency stop contactors,
and one motor protection relay. This
means that less space is required in
the control cabinet (Figure 5).
Tenfold increase in service life
Phoenix
Contact’s
hybrid
starter
technology uses a microcontrollercontrolled combination of wear-free
Figure 5 - The 22.5-mm hybrid motor starters combine four functions
in a single device, saving space in the control cabinet.
semiconductor technology and robust relay technology. While the semiconductors are in
charge of the switch-on and switch-off operations, the relay contacts conduct the current
without any loss. This results in smooth switching and significantly reduces the load on the
relay contacts. Moreover, the approach removes the need for elaborate and costly heat
sinks. Furthermore, the service life of hybrid motor starters is ten times that of purely
electromechanical switching devices (contactors).
The integrated internal load and locking circuits also significantly reduce wiring costs
because only six connections must be made for the main circuit. Four LEDs attached to the
front of the motor starter indicate device status – operating voltage, clockwise and counterclockwise motion, and error – in different colors. The rated motor current can be continuously
adjusted. For error reporting – to the control center, for example – a floating changeover
contact is also integrated into the device. Built-in protective circuits ensure that the hybrid
motor starters switch reliably even in harsh industrial environments. Because their control
inputs use so little current, the devices can be controlled directly through the PLC.
Summary
Hengst has been counting on the electronic
motor starters from Phoenix Contact for many
years. “The robust design and the simple wiring
and operation were the criteria that led us to
choose Contactron,” says Alfons Lehmbrock
(Figure 6). The tenfold improvement in service
Figure 6 - The robust design and user-friendliness of the
hybrid motor starters won over Alfons Lehmbrock, Hengst
project engineer.
life also proves advantageous, since Hengst
works
with
high
switching
frequencies.
Maintenance cycles become significantly longer, and the
installation's availability increases. The hybrid motor starters
can be used with motor types of up to about 3 kW for small
cargo elevators as well as conveyor belts.
Interface system for further
simplifying wiring
With hybrid motor starters from
Phoenix Contact’s Contactron
For further information vist:
product family, motors can be
www.phoenixcontact.co.uk
quickly and reliably switched and
reversed. Connecting the devices
to an interface system develops
If you are interested in publishing this article, please contact
Becky Smith: marketing@phoenixcontact.co.uk or telephone
0845 881 2222.
the efficient wiring concept further.
Hybrid motor starters and
command and reporting devices
are easily and clearly connected
with the technology (Figure 7).
This makes complex parallel
cabling at the control and signal
levels almost superfluous in large
systems with many consumers. A
gateway can be used to integrate
the motor starters into the
necessary fieldbus system, such
as Profibus, CANopen, Profinet, or
Ethernet IP.
Figure 7 - Connecting the hybrid motor
starters to the newly developed interface
system continues the efficient wiring
concept.