Concentric Motor Shaft Coupling for Synchronous Motors
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Solution Overview
Problem
Synchronous motors face limitations in handling high inertia and high torque loads, which restrict their efficiency gains and energy savings in applications with such characteristics.
Innovation Solution
A coupling capable of concentrically contacting the shaft of a synchronous motor is used to improve its interaction with high inertia and high torque loads, allowing for better synchronization and reducing vibration and wear, thereby enabling the motor to operate efficiently in applications previously suited only to induction motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If synchronous motors are used for high inertia and high torque loads, then efficiency and energy savings are improved, but the motor's ability to pull into synchronism deteriorates
Solution Approach 1:
The coupling is divided into two separate hubs (first hub for motor shaft, second hub for load shaft) connected by coupling elements, allowing each hub to be optimized independently for its specific function while working together to solve the synchronization problem with high inertia loads
Solution Approach 2:
The coupling acts as an intermediary device between the synchronous motor and the high inertia load, with the coupling elements providing a mechanical connection that facilitates smooth torque transmission and helps the motor pull into synchronism with the load
2Ease of operation
If conventional couplings are used, then the motor can be connected to the load, but vibration and wear increase
Solution Approach 1:
The coupling elements feature curved or spherical contact surfaces that provide smooth, concentric contact between the hubs, reducing vibration and wear compared to conventional flat or angular contact couplings
Solution Approach 2:
The coupling design changes the contact parameters between motor shaft and load shaft by using multiple coupling elements with specific geometries, material properties, and arrangement patterns that optimize torque transmission while minimizing harmful vibrations and wear
3Strength
If keyways and set screws are used for coupling, then the connection is secure, but the shaft is damaged
Solution Approach 1:
The invention extracts and eliminates the need for keyways and set screws from the coupling design, using alternative coupling elements that secure the connection through friction and geometric interlocking without requiring holes or fasteners in the shaft
Solution Approach 2:
The coupling replaces the traditional mechanical keyway and set screw system with a friction-based or geometric interlocking system that achieves secure connection without damaging the shaft, substituting a less invasive mechanical approach
Data Source
AI summary
A method comprises providing a line-start synchronous motor. The motor has a stator, a rotor core disposed within the stator, and a motor shaft. In accordance with a step of the method, a coupling for coupling a load to the motor is provided. The coupling has a motor shaft attachment portion configured to provide substantially concentric contact around the shaft at the end of the motor shaft. The coupling has a load attachment portion configured to operatively connect to a load. In accordance with a step of the method, a load is coupled to the motor with the coupling, and driven from start to at least near synchronous speed during steady state operation of the motor with a load coupled thereto. The motor shaft attachment portion may comprise a bushing assembly with matching and opposed tapered surfaces that cooperate to secure the motor shaft attachment portion around the motor shaft.