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Variable Frequency Drive Steering (VFD’s)

Updated: Feb 24, 2023

The use of variable frequency drives for pumpset motors offers significant advantages for ship steering applications. With a VFD motor pumpset, the steering can be ramped up to speed over the first and last 5 degrees of rotation to allow precise rudder positioning with no hydraulic shock.

VFD motor drives have the following advantages over constant running directional or servo valve pumpsets:

  1. Major reduction in electrical demand since the motor and pump only turn when a rudder angle change is underway.

  2. Major reduction in heat generation and consequent heat dissipation requirements due to the low duty cycle.

  3. Motor, pump and filter life are greatly extended due to the low duty cycle.

  4. Acceleration and deceleration of the rudder is continuously variable since motor speed depends on the rudder angle difference. This provides smoother and more accurate rudder positioning even at very high rudder rates.

  5. The steering is very quiet since the pump seldom runs.

Further advantages of Autonav VFD Control

6. Steering control and monitoring is provided with a large LCD colour touchscreen which is easy to use, intuitive, more compact, and provides more information than traditional steering control and alarm systems.

7. Connection from Bridge to MCR and steering compartment is with a single CAT5e data buss cable which is much easier to install, and more reliable than a traditional multi conductor cabling system.


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