Press 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.>>>>>>>>
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