Soft starters for harsh environment

Fairford SDF soft starters are being used in a Devon quarry to provide soft starting and stopping of motors used to drive pumps extracting water from the quarry workings.

The soft starters have been installed as part of three complete turnkey panel systems designed and installed by Portico Industrial Control Systems Ltd. The first system controls a 37kW pump extracting run-off water from new quarry workings. As a river runs through the site it was necessary for the quarry to provide a man-made reservoir to collect the run-off from the new workings. When the reservoir level reaches a certain point the pump is used to extract the water and pump it up to a new level where it is treated to remove heavy metals etc before being pumped into the river. The control panel for this pump is fitted with a SDF-14 soft starter which, in addition to its reliability and cost advantages, was chosen for its ease of installation.

The other two systems supplied by Portico control two pumps. The first, driven by a 45kW motor, takes surface water from the area where the operating machinery is located and pumps it into a settlement tank. A second prime mover, driven by a 75kW motor, then pumps this water up to the treatment area where it is treated before being discharged into the river. The first pump is controlled by a SDF-22 soft starter and the second by a SDF-24 unit.

Fairford’s SDF soft starter units feature simplified wiring that fits in the same space as a conventional Star/Delta Starter and provides motor protection by offering the benefits of both soft starting and soft stopping. The SDF system ramps up to an initial voltage, holding the voltage, and then ramping up to full volts without disconnecting the motor from the mains supply. This is said to eliminate the high current that can occur at the transition from Star to Delta.