A sweet way to fix voltages
15 Jan 2000
British Sugar's largest plant, at Wissington in Norfolk, operates thanks to a vast array of motors, all with differing power ratings. The plant processes 1.8million tonnes of sugar beet per year, with a peak daily output of 1500 tonnes of granulated sugar. Naturally, efficient operation is a must - but a power problem was causing costly downtime.
The motors are all driven by ABB's ACS 500 inverter drives, chosen because of their energy efficiency. But momentary fluctuations in the plant's voltage supply were causing the drives to cut out, resulting in downtime at various parts of the plant - something that British Sugar would have preferred to avoid.
The company installed contacters which operated within a wider voltage window. Another ABB product fitted the bill, says senior engineer Steve Ballantyne - the AF contactor range. Twenty such units have now been installed into the inverter panels, and early indications are promising.
Contacters are often vulnerable to changing voltages. If the voltage is too high, the contacts can close and `bounce' open again. The AF units use an electronic coil interface to regulate the current which closes the relays; this feature keeps them closed, even if the voltage varies.
