The technology can also be applied to thyristor-based power controllers such as solid-state relays, and to applications ranging from electrical heating to DC link voltages in variable-speed drives.
The technology “will deliver significant cost savings by allowing companies to replace a high-power soft-starter with two or more smaller units,” explains Fairford’s managing director, Mark Shepherd. “Larger power soft-starters are more expensive to manufacture compared to smaller versions because of a lack of economies of scale on production, approvals and testing.
“A Pluss control system means a spare soft-starter can be included on critical applications, ready to take over in the event of a fault on another soft-starter,” he adds. “Thermal load-sharing between several soft-starters working in parallel on one application also boosts reliability and the operating lifetime of the control system.”
The technology simply requires soft-starters to be joined via a communications cable. Software then synchronises them so that they operate alternately on each cycle of the input power.
“One soft-starter takes the load for one half of the cycle and the other soft-starter takes over on the rest of the cycle, effectively swopping the load between the two starters up to 100 times a second,” explains Fairford’s lead engineer, Gary Stephens. “The more soft-starters that are connected with Pluss technology, the greater the load-sharing.”
Soft-starters control the initial voltage to industrial electric motors for a jerk-free start, avoiding mechanical stresses or large jumps in energy consumption. In 1982, Devon-based Fairford became the first company in the world to design and produce a digital three-phase soft-starter with automatic energy optimising.
“Following the Brexit vote, the UK government is placing even more emphasis on UK manufacturing, especially by supporting innovative ideas,” says Shepherd, “so we are delighted to have gained a worldwide patent for this new technology and to have another global first for a British company."
Fairford is talking to some of the world’s leading automation companies on how to apply its new technology. It is also planning to market the technology via its global distribution network.