Case Study: Dewatering the Channel Tunnel

AuCom soft starters have been used since the 1990s to drain water from the Channel Tunnel linking Great Britain to Europe.

Soft starters were first selected to drain water during construction, and are still used to ensure smooth operation of this tunnel.

The Eurotunnel system consists of two rail tunnels, each 50 kilometres long, and a smaller service tunnel. Water is drained from the tunnels by large submersible pumps, and reliable operation is critical - there are more than 200 train movements in each direction every day.

Eurotunnel engineers sought a high-quality solution to control all pumping processes during excavation. Voltage disturbances, jammed pumps and fluid hammer could all bring this vital transport link to a standstill.

AuCom soft starters offer important features which keep the tunnel running smoothly:

Reduced current levels during starting reduce voltage disturbance which is important for weak or limited supplies.
Soft stop prevents water hammer, avoiding the possibility of serious damage to pipework. The soft starter ramps down the voltage supplied to the motor, causing a gentle decrease in pump and fluid velocity.
Start monitoring prevents damage to the pump if it stalls or jams. Instead of stepping through to full voltage and subjecting the pump and motor to damaging electrical and mechanical stresses, AuCom soft starters shut the plant down safely.

Extensive motor and system protection features make AuCom soft starters the obvious choice for such a critical application:

reverse rotation protection
motor over-temperature protection
overcurrent protection
phase loss protection
undercurrent protection

From the outset, the Eurotunnel engineers knew they needed to work with an experienced supplier who could guarantee maximum reliability. In an international tender process, they selected AuCom ahead of its competitors for three good reasons:

Experience. AuCom has many years experience with electronic soft start, and has a proven reputation within the pumping industry for reliability and engineering quality.
Product Range. AuCom offers a wide and versatile range of solutions. AuCom's low voltage solutions can be used on supply voltages up to 690 V, 50 Hz or 60 Hz, and are suitable for use with motors from 1 HP to 2000 HP.
Service. AuCom provides customer service that is second to none. The company is represented around the world and provided full on-site support during the tunnel construction.