Coaxial Dual-Motor Pool Pump Drive With Split Speed Control
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Solution Overview
Problem
Existing motor control systems for pool pumps are either expensive due to the need for high horsepower motors and control electronics for fully variable speed control or inefficient due to multi-fixed speed induction motors, which do not meet recent energy conservation and safety regulations.
Innovation Solution
A dual motor system with a first motor providing a lower speed range and a second motor providing a higher speed range, coaxially arranged on a common shaft, along with a motor control system that engages the second motor when higher speeds are required, utilizing a variable speed synchronous motor and an asynchronous induction motor respectively, and a flow control system to manage speed for efficient energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fully variable speed control is used, then speed control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the speed control system into two independent motor units: a synchronous motor for lower speed ranges and an induction motor for higher speed ranges. Each motor has its own control circuitry, allowing the system to achieve variable speed control without requiring a single complex high-power variable speed drive. This segmentation reduces overall system complexity while maintaining precise speed control in both ranges.
2Adaptability or versatility
If high horsepower motors with variable speed control are used, then speed control capability is improved, but cost increases
Solution Approach 1:
The patent segments the power requirement into two smaller motor units rather than using one large high-power motor with variable speed control. The synchronous motor handles lower speed ranges with moderate power, while the induction motor handles higher speed ranges. This approach reduces the cost of control electronics and makes the system more manufacturable while maintaining full speed control capability across the entire operating range.
3Device complexity
If multi-fixed speed induction motors are used, then device complexity is reduced, but energy efficiency deteriorates
Solution Approach 1:
The patent makes the control system dynamic by enabling continuous variable speed control through the coordinated operation of two motors. The synchronous motor provides variable speed control in the lower range, and the induction motor provides variable speed control in the higher range. This dynamic control allows the system to operate at optimal speeds for different loading conditions, significantly improving energy efficiency compared to fixed-speed multi-tap induction motors while keeping control complexity manageable through modular design.
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
The dual motor system reduces the size and cost of the variable speed drive, increases efficiency by minimizing power loss, and meets energy conservation regulations by providing fine control over speed ranges, thus optimizing energy usage in pool pumps and other applications.
Implementation Method 1
a first motor providing a lower speed range and a second motor providing a higher speed range, wherein the motors are coaxially arranged and aligned on a common axis defined by a common shaft and are configured to drive the common shaft
Data Source
AI summary
A dual motor system includes a first motor providing a lower speed range and a second motor providing a higher speed range, wherein the motors are coaxially arranged and aligned on and drive a common shaft, and a motor control system controlling the speed of the first motor and engaging the second motor as needed. The first motor is a variable speed motor providing a lower two-thirds of a full speed range, and the second motor is an induction motor providing the upper one-third in the form of one or more discrete fixed speeds. The system may include a transformer including a first winding tap which provides a first higher speed, and a second winding tap which provides a second higher speed. The system may also include a flow control system for automatically controlling the speed of the motors for particular applications, such as flow control in a pool.