Electric Azimuthing Dual Contra-Rotating Propulsion Drives
The PT. Marine Propulsion Solutions CRP-M SERIES of Azimuthing Dual Contra Rotating eliminates the problem of the single propeller inducing a rotating motion in its own wake. This reduces the efficiency of the propeller.
In order to recover this energy two propellers behind each other are used on dual shafts, also called a CRP and are driven by specifically designed permanent magnet motors built as an integral part of the Propulsor hub.
The ship’s Captain controls vessel speed by controlling the lead propeller speed with MPS software controlling the trailing propeller speed….. The result being to optimize propeller efficiencies regardless of vessel speed with efficient, silent and vibration free propulsion.
In development – Pending Release 1st Q 2018
MPS Propulsion introduces the Azimuthing Dual Prop-Contra Rotating Permanent Magnet Electric Propulsion Drive. The two propellers rotate in opposite directions and the pitch and loading of the propellers are designed such that the resulting rotational energy in the wake is zero. To reduce shaft vibrations the numbers of blades of both propellers are different, so that not all blades pass each other simultaneously. The diameter of the front propeller is often slightly larger than that of the rear propeller, to account for the contraction of the propeller wake and to avoid the rear propeller to hit the tip vortex of the front propeller.
Because the rotational losses are recovered by the rear propeller this makes it possible to reduce the rotation rate and thus the frictional losses without increasing the rotational losses. A CRP has a lower rotation rate and the increase of efficiency from a single propeller can be as high as 15%.