• About us

Case Story: Fox Luna


Fox Luna

INDUSTRY: Marine, Oil & Gas
TIMELINE: 2015 to present 


ADF P300 was selected for each of the 3 feeders
Siemens Sinamics 6-Pulse drives

Ever wondered where big cargo ships stop for fuel? Well, in many cases, the fuel is delivered directly to the cargo ships out at sea, and for this a type of vessel called bunker tanker is used. Swedish ship owner BRP operates the bunker tanker Fox Luna on the west coast of Sweden.

Fox Luna was built in 2008 in Norway. The largest loads on board consists of main propulsion, bow thruster and pumps, all powered by Siemens Sinamics 6-pulse drives. From the yard, Fox Luna was equipped with passive harmonic filters, installed to mitigate harmonics. Fox Luna was not complying with DNV-GL target levels, and with voltage harmonic levels reaching up towards 13% there was a real risk of damage to sensitive equipment onboard.


However, the passive filters were causing a lot of problems, eventually even causing an explosion on board. With faulty harmonic filters, Fox Luna was not complying with DNV-GL target levels, and with voltage harmonic levels reaching up towards 13% there was a real risk of damage to sensitive equipment onboard.

BRP was looking for a solution that could do the job reliably day in and day out and contacted Comsys for support.


The main concern was that without a working harmonic mitigation solution, Fox Luna was not complying to the DNV-GL regulations for harmonics. BRP was looking for a solution that would guarantee compliance with DNV-GL, and at the same time could operate reliably without break downs in the relatively tough environment that a marine installation is.

As always on-board ships, space is a premium, and replacing an existing harmonic mitigation installation adds further to this challenge. Fox Luna is not a big vessel, so a compact replacement solution was required. Even finding space for measurement current transformers turned out to be impossible.


Comsys performed a thorough study of the vessel under operation and based on the measured results an ADF P300 was recommended as a new solution. Both air cooled and liquid cooled solutions were evaluated, but in the end BRP decided to remove the faulty passive filters and replace them with a single liquid cooled ADF P300. Because of the very limited amount of space available, there was no room for current transformers, and it was decided to run the ADF in Sensorless mode.

The ADF P300 is a robust and proven active harmonic filter for marine installations. With Sensorless control, the Comsys ADF can be operated without installing current transformers which saves even more space.



The ADF P300 was installed in 2015. The system has been operating ever since, reducing THDu levels to well below the threshold for compliance with DNV-GL regulations and making sure Fox Luna can perform it´s important tasks without interruptions.

Fox Luna

With Fox Luna running at 90% of maximum
load/capacity, the ADF P300 is compensating
155A, only 55% of the possible utilization.

Download this case story

Enter your email address and we’ll send this case story straight to you!

IMPORTANT INFORMATION! By sharing personal information on this website you also agree to the use of this information by Comsys AB in accordance with the General Data Protection Regulation (GDPR). If you have any questions regarding the General Data Protection Regulation you can contact Comsys AB at or read more at https://www.datainspektionen.se/dataskyddsreformen (in Swedish) or https://www.eugdpr.org (in English) By continuing you agree to the use of personal information in accordance with GDPR.

NOTE! This site uses cookies and similar technologies. Unless you change browser settings, you agree to it.

© Comsys AB 2021 All rights reserved
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.