Wärtsilä Shaft Generator Systems

Wärtsilä Shaft Generator Systems generate onboard electrical power from the main engine instead of auxiliary gensets, reducing fuel consumption, emissions, maintenance and noise. Wärtsilä has delivered over 1000 shaft generator systems and has more than 60 years of experience.

How it works

A frequency converter supplies three-phase power at constant voltage and frequency to the mains while main engine speed varies, e.g. at different vessel speeds, in heavy seas or in combinator mode with controllable pitch propellers. The usable speed range can be defined from operational needs, for example 60% to 100% of main engine speed at constant output.

Key features

• PWM frequency converter with IGBT technology; no synchronous compensator needed
• THD in mains voltage below 5% in all operating states without filter circuits
• Only two components to install: shaft generator and frequency converter panel
• Water-cooled power electronics connected to the ship's fresh water system
• Geared shaft generator as standard brushless synchronous generator
• No step-up transformer for 400 V, 450 V, 690 V and 6.6 kV solutions
• Microprocessor-based digital control with integrated touch-screen monitoring, test and simulation
• Parallel operation with a second shaft generator and diesel gensets; selective short-circuit tripping
• Payback time of 2 to 4 years depending on system power

Configurations

• In the shaft line between a low-speed main engine and propeller
• Via power take-off on the reduction gear of a medium-speed main engine
• Via tunnel gear in the shaft line of a low-speed main engine

Shaft motor operation

With a PWM rectifier, the system can operate as a motor: booster propulsion in parallel with the main engine, take-home/take-away emergency propulsion with the main engine declutched, and Power Take In fed from the main switchboard.