Wärtsilä SAM Electronics Shaft Generators / PTO Shaft Generators (SG) are driven by the main engine to supply power to the mains. The power generation has to function properly also at changing speeds of the propulsion shaft, when the ship travels at different speed ranges, or in case of very fast speed changes caused by heavy seas. To allow a stable frequency and voltage in the mains while the main engine speed is changing – a frequency converter in PWM technology is used.

More and more vessels are equipped with these systems due to the following advantages:
– Reduction of maintenance costs – Lowering of fuel and lubrication costs
– Return on investment in 3 to 4 years Safety for ship and crew
– Low noise power generation -Smaller or less diesel generator sets
– Continuous parallel operation together (two SG systems) or with diesel generator sets

Also when using controllable pitch propellers it is highly economical to use a system with PWM frequency converter. By using the so called combinator mode it is possible to operate the main engine and the propeller with optimum efficiency. Meanwhile Wärtsilä also improved the PWM technology to our medium voltage systems. Up to 9MW of power is possible without step up transformer and without synchronous compensator. A break through in these days.

Together with SAMCon the converter of the Shaft Generator system can be used for adapting the frequency to 50Hz or 60 Hz. Wärtsilä SAM Electronics has provided more than 400 Shaft Generator systems with a high number of individual configurations.