Intervention on a dredge in the port of Le Havre

Intervention on a dredge in the port of Le Havre



Devos Vandenhove has recently been contacted by the big seaport of Le Havre for an urgent intervention on a breakdown of Leroy Somer variable speed drive. That variable speed drive is installed on board the La Gambe d’Amfard dredge. The nature of that atypical intervention has not been an obstacle for Devos Vandenhove, which has been able to respond fully to that particularity.

A dredge is a service ship, which helps to fight sand beds and siltation near ports. Its system is simple: the dredging is made through a dredge pump, whose speed is regulated in this case by a Leroy Somer variable speed drive composed of two MDS 470T coupled in parallel, of the Powerdrive’s range.

At the end of the day, when returning to the dredge’s port, the alarm went off in the pumphouse to signal a malfunctioning in the installation. A burning smell was felt and the variable speed drive was marked by burns marks.

Variateur Leroy Somer MDS 470T

Leroy Somer MDS 470T - Variateur de vitesse


Immediately after having been contacted by the big seaport of Le Havre, one of our technicians has moved there in the evening for a diagnosis. It turned out that the middle phase had burned down, probably due to a failed LEM measurement of current. The phase of the bottom has also been damaged. Both IGBT were thus burned and out of service, the intermediate bus, as far as it is concerned, has exploded.


The following elements have then been replaced:

  • 2 inverter modules

  • 2 rectifier modules

  • 3 current measurements

  • 1 coupler board

Even if a single LEM measurement of current was defective, three were replaced for the sake of the quality of the repair of the variable speed drive.

Due to the urgency of the intervention – the port, unable to afford to have a stationary dredge – spare parts were forwarded in the evening in rush delivery by taxi. Then, the technician has repaired the Leroy Somer variable speed drive in only one day and has made sure of its good restart. The pump was therefore able to function again and the dredge was ready to go back to sea.


Thanks to the reactivity of Devos Vandenhove and the rapid intervention of one of our technicians, the diagnosis and the repair were done in one day. The stop time of the dredge has been minimal and the work has not been impacted, which has consequently and significantly reduced operating losses.