Modes & Operation

The shaft generator has two modes of operation:

  1. Power Take-Off (PTO): The additional energy generated in the main engine is taken off by the shaft generator to produce electricity as an alternative to the four-stroke gen-sets; hence this mode is called PTO or Shaft generator mode.

*PTO can improve ship EEDI figures

  1. Power Take In (PTI): Power Take in (PTI) mode provides propulsion power to the shaft which boosts the main engine with temporary extra power. It can also be used as emergency backup machinery to propel the ship to the nearest shore if the main engine goes out of operation, thereby increasing the redundancy factor. This mode is also known as shaft motor mode.

*PTI can deteriorate the EEDI figures if used for increasing the ship’s speed.

Shaft Generator


A power Management System (PMS) is installed in the ship’s engine room to look after the safety and operation of the power-generating machinery, which includes an auxiliary generator, turbine generator, and shaft generator.

The Shaft Generator – The motor circuit breaker is usually closed, if not, an operator can close the circuit breaker via the PMS panel. This command is released if sufficient apparent power is available. The two modes explained above are controlled by the PMS of the ship.

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