Energy saving AC Motor drives from Stadt

The company Stadt AS in Norway has developed the new product, Stadt Stascho, over the past 5 years, based on their long experience in development of Megawatt AC motor drives for ship and industry.The Stascho product range goes up to 50 MW in voltages up to 15 kV, optionally also in higher voltage classes.
The most interesting feature of the new patented drives is:
Extremely low electric losses, less then 1 % at full load resulting in total electric system losses of only 5 % . Knowing that equivalent AC Drive systems based on i.e. 12 pulse configuration has system losses in the range 11-13 % - this new technology will have huge impact on energy consumption for the electric propulsion system.

Fuel- and NoX-reduction up to 45 %
Although fuel costs are to live with at the time being, we all know that these costs will increase again. Therefore it is important to plan for the future, and keep the running costs for the ships as low as possible. Fuel savings up to 45 % are achievable by using the Stadt Stascho in ship propulsion system. This is possible due to optimal mode operation of generator sets, and the low-loss electric AC-motor control for the propellers. Pollution from NoX etc is reduced equally.
The new Stadt Stascho is expected to be warmly welcomed in naval application, both for military and commercial vessels with gas – or diesel-electric propulsion systems. The low losses will save fuel in all working conditions for the ship, especially at high power. The difference from 13 % losses to 5 % is significant, and will result in a new way of evaluating the way that propulsion systems for ships will be designed in the future.
- New types of ships will most likely turn in to electric propulsion to save oil and pollution, says Hallvard Slettevoll, director of Stadt AS.

One of the reasons for the unique characteristics of the new Stadt Stascho drive technology, is that it is based on bidirectional Sinusoidal voltage and current, both toward the driving electric AC motor , and backward to the electric switchboard. The basis of this new technology comes from the company NFO Drives AB in Sweden, which has developed a patented inverter that controls standard AC-motors with a pure sinusoidal voltage and current. The Sinus-technology gives many advantages compared to the widely used Pulse Width Modulation - PWM technology, used by the waste majority of drives manufacturers in the world. The most important advantage, is that Sinus does not generate any disturbances at all, enabling the user to use unscreened power cables and standard AC motors without getting problems typically found in PWM driven applications, like bearings damages. It is also worth to notice that the STADT STASCHO Drive saves space and weight