Split Stator Winding for Balanced Rotor Loading

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing stator winding configurations for electric motors face issues with unbalanced rotor loading due to asymmetry, particularly in high-speed motors with low turns, leading to excessive losses and mechanical stress on components like shafts and bearings, and existing solutions for balancing windings are either impractical or costly.

Innovation Solution

The stator winding is split into two electrically separated systems that can be powered by separate frequency converters, with each phase consisting of two parallel branches connected in series, allowing for balanced operation even if one converter fails, thereby minimizing radial forces on the rotor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional stator winding configurations are used, then the motor can operate with standard winding arrangements, but unbalanced rotor loading occurs due to asymmetry leading to excessive losses and mechanical stress

Engineering Contradiction:
Improverotor loading balanceVSAvoidexcessive losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The stator winding is divided into two electrically independent systems (System 1 and System 2), each with its own set of windings connected to separate frequency converters. This segmentation allows independent control of each system, enabling balanced operation even when one system fails, thereby resolving the rotor loading balance issue while reducing energy losses

Inventive Principle:
Principle #1Segmentation

2Duration of action of stationary object

If conventional stator winding configurations are used, then the motor structure remains simple, but unbalanced radial forces cause mechanical stress on shafts and bearings reducing component life

Engineering Contradiction:
Improvecomponent design lifeVSAvoidradial forces on rotor
Core Design Contradiction:
Duration of action of stationary objectVSForce

Solution Approach 1:

By dividing the winding into two independent systems with separate frequency converters, the patent enables balanced control of radial forces. Each system can be independently adjusted to maintain force balance, reducing mechanical stress on shafts and bearings and extending component design life

Inventive Principle:
Principle #1Segmentation

3Reliability

If existing solutions for balancing windings are implemented, then rotor loading balance may be improved, but the solutions are either impractical or costly

Engineering Contradiction:
Improverotor loading balanceVSAvoidwinding configuration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the winding into two independent systems that can be controlled by separate frequency converters. This approach achieves balanced rotor loading through independent control without requiring complex winding reconfigurations or additional balancing mechanisms, maintaining practicality while improving reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables independent adjustment of electrical parameters (frequency, voltage, phase) for each winding system through separate frequency converters. This parameter control allows dynamic balancing of rotor loading without changing the physical winding structure, avoiding increased device complexity

Inventive Principle:
Principle #35Parameter changes

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 ensures balanced radial forces on the rotor, reducing mechanical stress and extending the design life of components, while also simplifying manufacturing and reducing costs by allowing efficient use of space and materials.

Implementation Method 1

Stator windings for electric motors are well known to those skilled in the art

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2779383B1Stator winding for an electric motor
Publication Date: 2021.08.25 INGERSOLL RAND IND US INC
  • EP2779383B1 patent drawingFigure 1
  • EP2779383B1 patent drawingFigure 2
  • EP2779383B1 patent drawingFigure 3a~3c

AI summary

An electric motor having a rotor core with a rotatable shaft extending therethrough, and a stator positioned radially outward of the rotor core is disclosed herein. The stator can include at least one pair of first and second coils circumferentially positioned on opposing sides of the rotor. Each pair of the first and second coils includes first and second elements electronically isolated from one another. A first frequency converter is electrically connected to a first conductive wire and a second frequency converter is electrically connected to a second conductive wire. The first conductive wire is wound about the first element of the first coil and the first element of the second coil in series and the second conductive wire is wound about the second element of the first coil and the second element of the second coil in series.