news release
from Control Techniques
For immediate release
ROAD TESTING SOUTH AFRICA STYLE
A remarkable device for the accelerated testing of highways or airport runways and
developed in South Africa, features modular AC drives from Control Techniques.
The Accelerated Pavement Testing device (APT) – the MLS10 - produced by MLS
Test Systems Pty Ltd of Stellenbosch, features contactless linear induction motors
eliminating drive train fatigue and wear. The MS10 can apply more than 100 000
wheel loads per day, each equivalent to a 12-ton axle load, onto a 3.6 metres long
stretch of road. The typical speed of the wheels is 6 m/s (22 kph).
The machine structure is a space frame 10 metres long, inside which four wheel
bogies, each fitted with dual 295/65 R22.5 truck tyres, run in a vertical loop. The
wheel bogies, linked together in an endless chain, are guided by two concentric sets
of steel guide rails. Dual, counter-rotating, 250-mm diameter steel guide wheels on
the bogies run between two sets of guide rails. Whilst a bogie runs along the bottom
section of the rails, the tyres are pushed down onto the pavement by a hydraulic and
compressed nitrogen gas system. In addition, whilst running, the entire machine can
be translated sideways, about 500mm to each side, on computer-controlled hydraulic
powered slides to simulate the lateral distribution of the wheel paths of different
trucks on a highway.
The machine has an on board a 132kW diesel generator and is fitted with transport
wheels on which it can be driven and steered at low speed under its own power.
The machine utilises Linear Induction Motors (LIM’s) from Force Engineering in the
UK to drive the bogies inside the machine and these are controlled by specially
configured modular Unidrive SPM AC drives. LIM’s, with their no-contact
characteristics and their high thrust and acceleration were the perfect choice for this
application, but they do require control by specially configured inverter drives. Control
Techniques has worked closely with Force Engineering for many years to produce
the optimum control characteristics for LIMs.
The drives give a soft-start action, maximum speed being determined by winding
design and supply frequency whilst torque and speed is controlled in several ways.
Control Techniques’ on-board second processor technology was used to run the
dedicated LIM Control Software Solution. The software was downloaded into an SM
Applications Plus module which requires no panel space as it is fitted into the interior
of the Unidrive SPM drive. This high-speed processor handles all motion control
calculations as well the complete machine logic control. The lateral position control
of the entire machine is also handled within the SM Applications Plus module.
Analogue sensors provide position feedback and the actual motion is done by
hydraulic actuators.
The machine I/O is networked to the SM Applications Plus processor module by
means of CTNet, Control Techniques’ own high-speed network, and Beckhoff remote
I/O cards. In this way the designers managed reliabily to network large quantities of
field I/O at very high communication speeds.
An operator interface is used to setup the machine operating parameters as well as
provide system diagnostics and fault reporting.
The modular nature of the Unidrive SPM’s power circuits helps with fitting into nonstandard enclosures – and was a major benefit for this application. The drive still
provides the full standard and optional features of the well-proven and popular
Undrive SP range, and is integrated using the same software tools for commissioning
and programming. The Unidrive SPM is extremely versatile, configurable into open
and closed loop modes, paralleled and load sharing, with active input and
regeneration, in multi-pulse configuration (12, 18, 24 etc.) or fitted on a common bus
for circulation of energy between drives.
The linear induction motors for the MLS10 Test System are supplied by Force
Engineering of Leicestershire, one of the world leaders in LIM technology. The
company has developed hundreds of bespoke designs – from just a few Newtons of
force up to many kiloNewtons - supplying companies throughout the world for
applications as diverse as rapid transit systems, amusement rides and materials
handling.
LIMs are used to move a steel bar a few millimetres or propel a seven tonne vehicle
up to 60mph in seconds! LIMs produce a linear thrust in a reaction plate and have
many advantages; no moving parts, silent operation, reduced maintenance, compact
size, fast response and ease of control and installation. They develop very high
acceleration and braking forces, with speed not limited by contact friction and no
gears means no backlash.
MLS Test Systems has extensive experience in electro-mechanical design and
pavement engineering. Its core business is the design and manufacture of research
and test equipment for the road and airport pavement industries.
-ends780 words
Notes to the Editor:
About Control Techniques
Control Techniques, an Emerson Industrial Automation company, is a world leader in the design,
production and marketing of electronic variable speed drives for the control of electric motors. Our
strategy is to concentrate on delivering drives and servo products that enhance the productivity of our
customers machines and processes.
We operate through a global network of Drive Centres and Application Centres that both distribute
product and add value by building our drive products into custom designed systems and by offering
the highest levels of customer service.
Our Control Techniques Drive Centres also provide us with invaluable feedback and market
intelligence so that we can further improve our products and service. This customer focused strategy
will enable us to continue to grow profitably.
Our competitive edge is based on our unique focus on drives, our strength in research and
development, our investment low-cost manufacturing and an effective worldwide marketing strategy.
For the best in drives information visit our website: www.controltechniques.com
About Emerson Industrial Automation
Emerson Industrial Automation, a business of Emerson, is a global technology provider that enables
productivity, efficiency and quality gains for customers across a spectrum of industries. Our products
include alternators, electric motors and drives, electrical distribution devices and mechanical power
transmission, fluid automation and ultrasonic joining solutions. Emerson brands include Appleton,
ASCO, Branson Ultrasonics, Browning, Control Techniques, Kop-Flex, Leroy-Somer, McGill, Morse,
Numatics, O-Z/Gedney, Rollway, SealMaster, and System Plast. For more information, visit
www.EmersonIndustrialAutomation.com.
About Emerson
Emerson (NYSE:EMR), based in St. Louis, Missouri (USA), is a global leader in bringing technology
and engineering together to provide innovative solutions to customers through its network power,
process management, industrial automation, climate technologies, and appliance and tools
businesses. Emerson’s sales in fiscal 2009 were $20.9 billion. The company is ranked 94th on the
Fortune 500 list of America’s largest companies. For more information, visit www.Emerson.com.
For editorial information contact:
Katie Williams, Press Officer, Control Techniques Ltd, Drive Centre Marketing,
Ty Rheoli, Unit 79 Mochdre Industrial Estate, Newtown, Powys SY16 4LE
Tel: 01686 612900. Fax: 01686 612999.
katie.williams@controltechniques.com
For Sales Enquiries Contact:
Control Techniques UK Drive Centre, Stafford Park 4, Telford, Shropshire TF3 3BA
Tel: 01952 213 700 Fax: 01952 213 701
Uksales@controltechniques.com