Tapped Stator Winding Switching for Wider Constant Horsepower Range
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Solution Overview
Problem
The constant horsepower speed range of electric motors is limited by breakdown torque at base speed and increasing back electromotive force (EMF) with speed, restricting high-speed operation in applications requiring wide speed ranges.
Innovation Solution
A tapped winding stator design with adjacent teeth and slots, where coils can be selectively bypassed using switches, reducing the number of effective conductors and increasing flux, allowing for enhanced torque and reduced EMF.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the number of conductors is increased to increase torque, then torque increases, but back EMF increases with speed which limits high-speed operation
Solution Approach 1:
The stator winding is divided into multiple coils with taps that can be selectively connected or disconnected. This segmentation allows the effective number of conductors to be varied, enabling torque enhancement at lower speeds while limiting back EMF at higher speeds through selective bypassing of certain coil sections.
Solution Approach 2:
The winding configuration is made dynamic through switches that can change the connectivity of coil taps during operation. This allows the motor to adapt its effective conductor count based on operating conditions, optimizing torque at base speed while reducing back EMF impact at higher speeds to extend constant horsepower range.
2Force
If breakdown torque is increased at base speed, then torque capability improves, but the constant horsepower speed range is limited
Solution Approach 1:
The effective number of conductors is changed by selectively bypassing coil sections through taps and switches. This parameter change allows the motor to achieve higher breakdown torque at base speed when needed, while extending the constant horsepower speed range by reducing effective conductors at higher speeds to limit back EMF.
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 tapped winding stator extends the constant horsepower speed range of electric motors by increasing torque and reducing back EMF, enabling higher operational speeds with controlled losses and voltage adjustments.
Implementation Method 1
reducing the number of effective conductors and increasing flux, allowing for enhanced torque and reduced EMF
Data Source
AI summary
The disclosed embodiments describe a tapped winding stator for use in an electric motor. In some embodiments, the electric motor includes a stator body. In some embodiments, a plurality of teeth that are adjacent in a circumferential direction. In some embodiments, a plurality of slots are formed between the plurality of teeth. In some embodiments, a plurality of coils are mounted in each of the plurality of slots. In some embodiments, the plurality of coils are tapped in a configuration that allows the stator to selectively bypass one or more of the plurality of coils in operation. A plurality of switches are electrically coupled between the configuration and a respective phase supply to the electric motor, each of the switches having at least a first position and a second position.