Motor Brake Functional Test Using Electromagnetic Torque

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Solution Overview

Problem

Existing brake testing methods for motor-driven loads are costly, energy-intensive, and require additional space and complex wiring, especially when implementing redundant braking systems to ensure safety against falling loads during vertical travel.

Innovation Solution

A method for functional testing of a brake that determines a single basic parameter value, such as motor current, to assess the brake's holding capacity, allowing for the use of existing components and direct measurement, independent of machine data, and enabling efficient testing of holding capacity in successive sections with minimal system influence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a redundant braking system with multiple brakes is implemented to ensure safety against falling loads, then the safety and reliability of the drive system is improved, but the device complexity, installation space requirements, wiring complexity, and control effort increase significantly

Engineering Contradiction:
ImprovesafetyVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The motor itself serves as the testing device for the brake. The motor's electromagnetic torque is used to apply controlled forces against the engaged brake during operation, eliminating the need for separate testing equipment. This self-service approach maintains safety testing capabilities while avoiding additional complex test system infrastructure

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The motor performs multiple functions: it drives the load during normal operation and simultaneously serves as the testing device for brake functional testing. The same motor components (torque, speed control) are used for both production and safety testing purposes, reducing overall system complexity

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

2Reliability

If a redundant braking system with multiple brakes is implemented, then the safety and reliability of the drive system is improved, but the installation space required increases

Engineering Contradiction:
ImprovesafetyVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The motor serves dual purposes as both the drive device and the testing device. By using the motor's own electromagnetic torque for brake testing during operation, no separate testing equipment or additional space for test devices is required

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The testing function is merged with the motor's normal operational functions. The same motor components (torque generation, speed control) are utilized for both driving the load and performing brake safety tests, consolidating functions into existing hardware rather than adding separate testing infrastructure

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a redundant braking system with multiple brakes is implemented, then the safety and reliability of the drive system is improved, but the wiring and control effort increase

Engineering Contradiction:
ImprovesafetyVSAvoidwiring
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The motor's control system automatically performs brake testing during normal operation without requiring separate control circuits or additional wiring. The existing motor control hardware manages both drive functions and safety testing functions

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The motor control system performs multiple functions: controlling the motor for load driving and simultaneously controlling the brake testing sequence. The same control circuitry and wiring infrastructure are used for both operational control and safety testing

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

4Reliability

If larger motors and brakes are used to accommodate the additional moment of inertia from a second brake, then the reliability and holding function are improved, but the size of drive components, energy consumption, and cost increase

Engineering Contradiction:
Improveholding functionVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The motor's electromagnetic torque during normal operation is utilized to perform brake testing, eliminating the need for separate high-power testing equipment. The testing function leverages the motor's existing energy output rather than requiring additional energy-intensive test devices

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The brake testing uses partial electromagnetic torque from the motor during operation rather than requiring full-power separate testing equipment. The testing sequence applies controlled torque levels sufficient for brake testing without needing excessive motor capacity

Inventive Principle:
Principle #16Partial or excessive action

5Measurement precision

If traditional brake testing methods are used that determine maximum holding force, then the brake's holding capacity can be verified, but the testing requires the load to descend at minimum speed and is not suitable for suspended loads

Engineering Contradiction:
Improveholding force measurementVSAvoidapplicability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The testing method transitions from static maximum holding force measurement to dynamic operational testing. The brake is tested during actual motor operation with the load suspended, verifying brake function under realistic dynamic conditions rather than requiring controlled descent at minimum speed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The motor's operational characteristics (torque, speed control) are used to perform the testing, making the testing adaptable to various operating conditions including suspended loads. The same motor control that drives the load also performs the brake testing function

Inventive Principle:
Principle #25Self-service

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 method provides a cost-effective and energy-saving means to assess brake safety, using existing components and direct measurement, ensuring reliable and reproducible results while minimizing system influences and allowing for efficient brake maintenance planning and safety improvements.

Implementation Method 1

a value of a basic parameter, in particular a motor current, a flux, a DC voltage, a magnetization, a fluid pressure, a torque or a similar state variable, can be assigned to the respective operating state of the motor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

in a second step, the application of the brake at a first position of the motor; in a third step, the application of a second value of the basic parameter to the motor, so that the motor acts against the applied brake

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

when this first value of the basic parameter is present; the motor holds the load against gravity

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP2126536B1Device and method for a functional test of a brake
Publication Date: 2019.01.16 SEW EURODRIVE GMBH & CO KG
  • EP2126536B1 patent drawingFigure 1

AI summary

A method for a functional test of a safe single-circuit brake of an electric motor, the electric motor comprising a stop brake, characterized in that the engine builds up defined torque against the stop brake.