Electric Motor Test System Cogging Torque Measurement

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Solution Overview

Problem

Existing electric motor test systems require time-consuming and labor-intensive alignment procedures to accurately measure cogging torque, often resulting in misalignment and inaccurate measurements.

Innovation Solution

An electric motor test system that connects the electric motor, dynamometer, and cogging torque measurement motor without detaching the motor from the dynamometer, using a connecting/disconnecting mechanism to facilitate cogging torque measurement while preventing high-speed damage to the cogging torque measurement motor, and employing a speed reducer for low-speed stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the electric motor is detached from the dynamometer and connected to a dedicated cogging torque measurement device for measurement, then the cogging torque can be measured, but the measurement process becomes time-consuming and labor-intensive due to alignment procedures

Engineering Contradiction:
Improvecogging torque measurement accuracyVSAvoidtime for alignment and reconnection
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent combines the dynamometer and cogging torque measurement device into a single integrated system. The dynamometer's rotating shaft can function as the measurement shaft for cogging torque measurement, eliminating the need for separate measurement equipment and alignment procedures. This merging allows both performance testing and cogging torque measurement to be conducted without detaching the electric motor.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dynamometer is designed with multi-functionality to serve both as a performance testing device and as a cogging torque measurement device. By configuring the dynamometer's rotating shaft to also serve as the measurement shaft, the system can perform multiple functions without requiring separate dedicated equipment, thereby saving time and reducing operational complexity.

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

2Measurement precision

If the electric motor is detached and reconnected for cogging torque measurement, then measurement can be performed, but misalignment such as centering errors may occur leading to inaccurate measurements

Engineering Contradiction:
Improvecogging torque measurement accuracyVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent merges the measurement shaft function into the dynamometer's rotating shaft, eliminating the need for repeated detachment and reconnection. This integration ensures consistent alignment since the shaft configuration remains unchanged, thereby preventing misalignment errors and improving measurement reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system is pre-configured with the measurement shaft integrated into the dynamometer's rotating shaft structure. This preliminary arrangement ensures that proper alignment is maintained by design, eliminating the need for repeated alignment procedures and preventing misalignment errors before they can occur.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If the cogging torque measurement motor is connected to the dynamometer, then cogging torque can be measured, but the motor may be damaged during high-speed regular tests

Engineering Contradiction:
Improvecogging torque measurement convenienceVSAvoidmotor durability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent implements a dynamic connection system where the cogging torque measurement motor is selectively connected to or disconnected from the dynamometer based on the test mode. During cogging torque measurement, the motor is connected to drive the rotating shaft at low speeds. During regular high-speed performance tests, the motor is disconnected to prevent damage from high-speed rotation, thus maintaining motor durability while enabling convenient measurement when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system pre-configures the connecting/disconnecting mechanism to automatically switch between measurement mode and test mode. Before high-speed regular tests begin, the mechanism preliminarily disconnects the cogging torque measurement motor from the dynamometer to prevent damage, while maintaining the capability to reconnect for measurement when required.

Inventive Principle:
Principle #10Preliminary action

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

Enables easy and accurate measurement of cogging torque without the need for alignment, preventing motor damage during regular tests and simplifying the system configuration by using a single torque sensor for both cogging and regular torque measurements.

Implementation Method 1

measure the torque generated between the electric motor and the dynamometer

Methodology Applied
Scientific EffectTorque measurement: Torque

Implementation Method 2

transmitting the rotation of the cogging torque measurement motor to the electric motor

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP3190397B1Electric motor test system
Publication Date: 2020.02.12 HORIBA LTD
  • EP3190397B1 patent drawingFigure 1
  • EP3190397B1 patent drawingFigure 2
  • EP3190397B1 patent drawingFigure 3

AI summary

In order to easily and accurately measure the cogging torque of an electric motor, the present invention includes a dynamometer 10 connected to an electric motor 200, a torque sensor 30 adapted to measure the torque of the electric motor 200, and a cogging torque measurement motor 50 for measuring the cogging torque of the electric motor 200, and is configured such that when measuring the cogging torque of the electric motor 200, the electric motor 200, the dynamometer 10, and the cogging torque measurement motor 50 are connected.