August 2015
|
World Coal
|
63
Unlocking
its
Mingming He, ABB Engineering,
China,
describes new developments
in drive and control solutions for
armoured face conveyors.
rmoured face conveyors (AFCs) are
widely used in underground coal mining.
With the aim of increasing production,
more and more research is being
undertaken to build larger AFCs that are suitable for
larger production. In China, many coal mines with an
output over 10 million tpy have gone into operation in
the past few years. At these mines, AFC widths have
increased to 1000 – 1200 mm, with total power up to
2 x 855 kW – 2 x 1200 kW. In these circumstances,
traditional drives and controls cannot fulfill the
operational requirements of the AFC.
Variable frequency drive (VFD) converters are
becoming the new drive solution for AFC motors.
Thanks to direct torque control (DTC) technology, the
motor can gain up to 200% torque output at zero
speed, which successfully solves the problem of
starting with a heavy load. Ramp start can reduce the
shock during machine start.
In addition, new speed control technology, based
on the detection and calculation of the actual coal
volume, is now able to bring coal transportation
systems an extra 15% energy efficiency, while
reducing the equipment wear during operation at the
same time.
New drive and control solution
for AFCs
The new systems consist of the following (Figure 1):
1.
Drives (VFDs based on DTC):
n
Ex‑proof drive system.
potential
A
