Electrical Machine Rotor Braking Element and Overload Clutch

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Solution Overview

Problem

In rail and road vehicles equipped with electrical machines, a winding short-circuit can cause the rotor to continue rotating without external voltage, leading to induced voltage, arcing, and heat losses that can damage the stator insulation and conductor windings, necessitating a mechanism to prevent further damage and heating.

Innovation Solution

An electrical machine with a braking element and a release device, including a safety clutch triggered by the braking element, separates the rotor from the wheelset when a fault occurs, preventing induced voltage and heat buildup by allowing the braking element to generate a torque that activates the overload clutch, disconnecting the rotor from the drive train.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the rotor continues to rotate without external voltage supply, then the rotor can maintain its rotational motion, but induced voltage and heat losses occur that can damage the stator insulation and conductor windings

Engineering Contradiction:
Improverotor rotation durationVSAvoidinduced voltage and heat losses
Core Design Contradiction:
Duration of action of moving objectVSObject-affected harmful factors

Solution Approach 1:

The braking element is extracted from the rotor and placed in the air gap to create a mechanical braking system that stops the rotor without electrical connection, eliminating induced voltage and heat losses while maintaining rotor rotation duration control

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The braking element acts as an intermediary between the rotor and air gap, creating friction-based braking torque that stops the rotor mechanically rather than through electrical disconnection, thereby preventing harmful induced voltage and heat effects

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a braking element is released from the rotor into the air gap to generate braking torque, then the overload clutch can be triggered, but the device complexity increases

Engineering Contradiction:
Improvefault protection capabilityVSAvoidbraking element and release device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The braking element serves dual functions: it acts as both a braking mechanism to stop the rotor and a triggering mechanism for the overload clutch, combining multiple protective functions into a single component to reduce overall device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The braking element is designed to perform multiple functions simultaneously: generating braking torque to stop rotor rotation, triggering the overload clutch mechanism, and providing fault protection, thereby reducing the need for separate dedicated components

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution effectively prevents further damage and heating by disconnecting the rotor from the wheelset, ensuring the electrical machine can be safely shut down and reducing the risk of insulation failure and overheating, thereby enhancing operational reliability and safety.

Implementation Method 1

By means of the braking element, a frictional force is generated, for example

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3469692B1Secure electrical machine
Publication Date: 2021.03.03 SIEMENS MOBILITY GMBH
  • EP3469692B1 patent drawingFigure 1
  • EP3469692B1 patent drawingFigure 2~4
  • EP3469692B1 patent drawingFigure 5~6

AI summary

The invention relates to an electrical machine (2) having a braking element (16) and a release device (14), wherein a rotor (4) of the electrical machine (2) comprises said braking element (16) and release device (14). The electrical machine (2) is located, for example, in a rail vehicle (10). In order to brake the rotor (4) of the electrical machine (2) in the event of an error in the drive train, an overload torque is generated by said electrical machine (2). An overload clutch (12) is triggered by this overload torque.