Severn Trent Water is saving thousands of pounds in energy and maintenance costs since replacing two old drives from the 1980s with the latest ABB standard drives at its Ladywood sewage pumping station in Ironbridge, Shropshire.
The combined savings mean that the new drives will pay for themselves in well under two years, whilst giving improved reliability. The drives were supplied by ABB Drives Alliance Partner, Central Electrical.
“The existing drives were over 20 years old and had reached the end of their life expectancy. Spare parts were extremely expensive and difficult to get hold of,” says Glen Hickman, engineer of Central Electrical. “When one of the drives broke down, the cost for a single replacement part was as high as £2,500.”
“The old units were pretty well obsolete and we wanted a modern equivalent that we could rely on,” confirms Colin Davies, maintenance supervisor for Severn Trent’s sewerage operations in Shropshire.
Central Electrical initially replaced one of the old drives when it failed and then monitored the performance of the new ABB standard drive compared with the remaining older version.
The tests confirmed that by replacing the older technology with a new ABB standard drive, Severn Trent was saving 5.5 kW per hour for the same pumping duty, which adds up to an estimated energy saving of £1,700 per year. So even without the considerable maintenance savings, the new drive should pay for itself in just over two years.
Central Electrical was then asked by Severn Trent to replace a second old drive when it failed a few months later. “The pumping station has been trouble free since the new drives were installed,” confirms Davies.
As the ABB standard drive took up 80% less space than its predecessors, the retrofit was easy.
Removing the old drives at Ladywood and installing and commissioning the ABB standard drive took less than eight hours. This was helped by the relative simplicity of the electrical installation. “The old drives needed a lot of complex wiring to interface with the pumping station control system,’ says Hickman. “In fact, the wiring was so complex that it needed a dedicated control panel. The new installation needs only a few wires,“ he adds.
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