26 years of underground traction control and support

31st March 2006

A leader in the design, manufacture, commissioning, refurbishment and repair of underground loco controllers, loco battery chargers and other surface and underground electrical and electronic equipment, Aztec Electronics supplies both off-the-shelf components and systems as well as tailor-made products.

Since its establishment in 1979, Aztec has become a leading supplier to the mining industry.

In 2005, Aztec unveiled its new IGBT loco logic to complement the Loco Manager controller. The MOSCON and IGBT loco controllers were designed and manufactured for both single and dual-motor applications and are SANS 1809:2003 certified. Their rugged and integrated safety features have proved to endure the harsh underground environment.

The company supplies controllers for applications ranging from small battery-powered locos to large multiton trolley locos. The loco controllers feature acceleration delay slip avoidance, an integrated electronic tachometer, fault condition indicators, a handle test facility, modular components, neutral braking, plug braking, opto switches for speed control, silent stepless operation as well as speed and battery- condition indicators.

As programmable controllers, their range of safety features include continuous driver detection, a current limit, an earth-leakage monitor, emergency braking, fail safe, neutral detection, over-voltage protection, overspeed protection, reverse-polarity protection, spike suppression coils, stalled motor protection, thermal protection, under-voltage protection as well as wheel-slip protection.

With its own research-and-development department, and manufacturing, testing and repair workshops, Aztec represents and supplies products from the most prominent engineering, control and instrumentation companies in the US and the UK. These include Albright, Cableform, Curtis Instruments and Sevcon. Aztec’s controllers include contactors from Albright and instrumentation from Curtis. Albright is the most extensively used heavy-duty dc contactor in the world. The company uses only the best quality materials, including silver alloy contact tips. As the sole South African agent for Cableform, Aztec has been largely successful in the installation and commissioning of Cableform controllers on 10-t, 12-t , 24-t and 27-t trolley locos in various South African mines. The third generation of large motor controls (LMC) from Cableform brings mine-proved solid-state performance and reliability to equipment powered by large dc motors. LMC controls use microprocessor-driven IGBT devices for the control of traction motors and other systems in scoops, haulers, shuttle cars, locomotives, personnel carriers and utility vehicles. They are built for equipment drawing power from trolley lines, batteries, trolley/battery combinations, reeled cable and ac/dc supplies. These controls power dc motors running on supplies from 72 to 600 Volts dc. It produces up to 1 300 A in motors without a bypass and generates maximum motor torque at all speeds. The LMC’s microprocessor controller runs IGBTs at high frequencies from 2 KHz up to 10 KHz. Motors receive 2 000 to 10 000 pulses of dc per second from LMC controls.

LMC controls eliminate the miscommutation, bypass and contactor problems found in SCR controls.

Total machine control is available through the LMC’s microprocessor. Built for use in an extensive range of new and old equipment, these controls are the maintenance and performance standard for installation in all dc-powered vehicles. LMC technology results in greatly simplified circuits which provide safe, reliable, energy- efficient operation where trouble-shooting is simple. Aztec’s BATCON underground loco battery charger uses a rugged transductor control design.

The electronically-controlled BATCON is designed to taper charge between 30 and 99 traction cells, ranging from 400 Ah to 1 000 Ah. Aztec offers complete product support and a 24-hour emergency backup.