STEALTH AC Propulsion Technology for the All-Electric Naval Ships

STADT AS is a leading company in AC drives and integrated electric propulsion systems for ships. Our latest product is the No-Loss innovative electric propulsion system.

STADT celebrated its 30th anniversary as a maritime technology company in December 2015, and moved in to its modern Maritime Center in Gjerdsvika, western Norway.

By the end of 2015, approximately 31 ships in different categories had been using the No-Loss drive technology.

Marine drives for electric propulsion systems

Based on 30 years of experience, the STADT No-Loss electric propulsion system is our fifth generation of innovative electric propulsion systems for ships. It is available in models from 100kW up to 80MW, with low and medium voltages up to 15kV.

The system will reduce your fuel consumption to a minimum, and leads to a major reduction of pollution from NOx, SOx and CO2. It also performs silently without any electric disturbances.

No-Loss AC drives for propulsion systems

The STADT No-Loss electric propulsion system is based on four years of research and development.

Company director Hallvard Slettevoll describes the new system as a 'breakthrough in technology', because it manages to combine the unique features of pure sinusoidal electric power, both for the main switchboard, along with the electric motors and other electric consumers, at minimum cost and space occupation.

Sinusoidal waveform on voltage and current ensures that there will be absolutely no interferences from inverter drives to other sensitive electronic equipment on the ships, such as radars, echo sounders, and seismic research instrumentation, as well as guaranteeing no bearing damages, and an absolute minimum of acoustic noise from electric motors and drives.

This is in contrast to the approach from other well-known electric drives suppliers, whom have delivered systems with a very high degree of electric pollution / noise in their main switchboard grids, as well as EMI (EMC) to the surroundings.

The idea to create unique solutions based on sinusoidal pure electric power is an approach that STADT has developed in close co-operation with the Swedish company NFO Drives. The sinus technology is patented by NFO and STADT.

Space-efficient and noise free electric propulsion system

Another major advantage with this new system is the space saving fact, since the big propulsion transformers are not needed. THD level of less than 2% is achieved.

Robust and sustainable technology

Another major advantage of the STADT No-Loss technology is high-reliability and a long lifespan of 25 years and more.

This is accomplished in a patented way of using different parallel technologies, redundant to each other, and at the same time using far less components in the drive system.

System integration

STADT has extensive experience in system design and integration for different kinds of ship projects. Our broad range of system components, in different types of technologies, enables us to design optimum solutions for each individual project.

Contact Details

Molovegen 2
N-6083 Gjerdsvika
Contact: Mr Hallvard Slettevoll (sales contact)
+47 7002 5800

Available White Papers


STADT STASCHO 15 January 2016 STADT STASCHO is a No Loss AC drive that supplies sinusoidal voltage and current to the electric motor and back to the main switchboard.


The Guideline to Electric Propulsion 08 April 2015 STADT STASCHO is a No Loss AC drive that supplies sinusoidal voltage and current to the electric motor and back to the main switchboard. This gives very low harmonic disturbances without using transformers or filters. LV and MV for high power models.


STEALTH AC Drives for the Full Electric Warship 15 November 2012 During the past four years, STADT has demonstrated a new AC no-loss drive technology for electric propulsion.