Functional Limits Example: Turbocharger Bent Blade Detection A bent - - PowerPoint PPT Presentation

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Good Blades Bent Blade A bent bade will create sub-band harmonics with almost no impact on primary 7th order harmonics

7th Order - Primary Sub-band Harmonics

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Demonstration:

• First convert to Rev

domain for order analysis

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Triggers locate rev position where speed criteria is met

Demonstration:

• Compute the Power

Spectrum,

• Restrict

computation to a fixed speed range using triggers for repeatability

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Demonstration:

• Compute the

Liftered Spectrum

• Used later to

‘flatten’ the Power spectrum

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Demonstration:

• Use Feature Math
• perations to divide

by Liftered spectrum

• ‘flatten’ the Power

spectrum

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Demonstration:

• Use the Functional

limits Editor to Create an Upper Limit function to use in exceedance computations

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Demonstration:

• Apply the

functional limit and produce an Out of Limit List of points exceeding the limit

• Use % of limit as

the unit of exceedance and sum the Ool List to form a metric

Meaningful Metrics for Automated Test

Functional Limits – Example: Turbocharger Bent Blade Detection

Demonstration:

• Form a decision for

Pass/Fail

• Include other

metrics that look for extreme exceedance by any

• ne peak