Propeller Pitch Control Using Variable Speed Drive
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Solution Overview
Problem
The existing propeller pitch control systems require continuous operation of an electric motor, leading to high energy consumption and rapid wear, as they need to maintain a speed of rotation equal to or close to the propeller shaft speed to ensure constant pitch.
Innovation Solution
A propeller pitch control system incorporating a variable speed drive with three rotors, where the drive, control, and outlet rotors are coupled to rotate proportionally with the propeller shaft, motor, and transmission members, allowing mechanical power to be derived from the propeller shaft, reducing reliance on the motor and minimizing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric motor operates continuously to maintain propeller pitch, then the pitch control is maintained, but energy consumption increases and wear accelerates
Solution Approach 1:
The motor operates intermittently rather than continuously. The control system monitors the difference between actual and reference pitch values, activating the motor only when pitch correction is needed. This periodic operation reduces energy consumption while maintaining pitch control stability through targeted interventions rather than continuous operation.
Solution Approach 2:
The propeller system utilizes its own rotational energy and pitch feedback mechanisms to maintain control. The control system leverages the existing rotational motion of the propeller shaft and the natural pitch response characteristics, reducing reliance on continuous motor intervention. The system serves itself by using its operational parameters to trigger corrective actions only when necessary.
2Reliability
If the electric motor operates continuously to maintain propeller pitch, then the pitch control is maintained, but wear on motor components increases
Solution Approach 1:
By implementing periodic rather than continuous motor operation, the system reduces cumulative wear on motor components such as bearings, brushes, and windings. The motor activates only during pitch correction events, extending component lifespan while maintaining pitch control stability through timely interventions.
Solution Approach 2:
The system uses the propeller's own operational characteristics and feedback mechanisms to minimize motor involvement. By leveraging the natural pitch response and rotational energy already present in the system, the motor experiences reduced duty cycles, thereby extending its operational life while maintaining control reliability.
3Reliability
If the motor speed matches propeller shaft speed to maintain constant pitch, then pitch stability is achieved, but energy consumption increases
Solution Approach 1:
The motor operates periodically to correct pitch deviations rather than continuously matching propeller shaft speed. The control system activates the motor only when pitch error exceeds a threshold, allowing the propeller to maintain constant pitch through targeted corrections rather than continuous synchronized operation, thereby reducing power consumption.
Solution Approach 2:
The propeller system maintains pitch constancy by utilizing its own rotational momentum and pitch feedback characteristics. The motor provides supplemental assistance only when natural pitch stability is compromised, allowing the system to self-maintain pitch constancy most of the time while consuming minimal motor power.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces energy consumption and wear by allowing the transmission ratio to be controlled, enabling the propeller pitch to be adjusted without continuous motor operation, thus conserving energy and extending system lifespan.
Implementation Method 1
the variable speed drive is configured to drive the outlet rotor in rotation at a speed that is a first predetermined function of the speeds of rotation of the drive and control rotors
Implementation Method 2
said drive, control, and outlet rotors are coupled to rotate respectively with a drive member that is the propeller shaft, with a control member, and with the outlet member of the transmission, and consequently the speeds of rotation of the drive, control, and outlet rotors are proportional respectively to the speeds of rotation of the drive, control, and transmission outlet members
Data Source
AI summary
A control system for controlling the pitch of a propeller, the system including a propeller shaft, a blade swivel device having a rotary control element suitable for placing the blades in an angular position corresponding to a desired propeller pitch, and a transmission presenting an outlet member coupled in rotation with the rotary control element of the blade swivel device. The transmission includes a variable speed drive having drive, control, and outlet rotors that are coupled in rotation respectively with the propeller shaft, with a control member, and with the outlet member of the transmission. With the variable speed drive, the speed of rotation of the outlet member of the transmission is a predetermined function of the speeds of rotation not only of the propeller shaft, but also of the control member.