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Hent Vibrationskompendiet her - Fredericia Maskinmesterskole

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Vibrationsmåling – vibrationsanalyse – balancering<br />

Indholdsfortegnelse:<br />

Teknikker og software til at forudsige rette vedligeholdsaktivitet ..................................................................................6<br />

Indledning ...................................................................................................................................................................6<br />

Gennemførelse af en plan for tilstandsbaseret vedligehold.............................................................................................6<br />

Indhold af målerapport mv..........................................................................................................................................7<br />

Eksempel 1: Sporing af lejeskade i en vekselstrømsmotor ved hjælp af vibrationsanalyse og elektrisk måling<br />

(spændingsmåling: aksel til jord) ....................................................................................................................................8<br />

Cost benefit analyse: .................................................................................................................................................10<br />

Eksempel 2: Deformation af en prægerulle på en papirkonverteringsmaskine.............................................................11<br />

Konklusion....................................................................................................................................................................12<br />

Vibrationer:.......................................................................................................................................................................13<br />

Hvorfra kommer vibrationer? .......................................................................................................................................13<br />

Vibrationsparametre:.....................................................................................................................................................14<br />

Acceleration, hastighed og forskydning....................................................................................................................14<br />

Accelerometer. ..................................................................................................................................................................14<br />

Det piezoelektriske accelerometer. ...............................................................................................................................14<br />

Accelerometrets opbygning. .........................................................................................................................................15<br />

Accelerometertyper.......................................................................................................................................................16<br />

Accelerometerets karakteristika. ...................................................................................................................................17<br />

Accelerometrets frekvansområde..................................................................................................................................18<br />

Måleteknik: .......................................................................................................................................................................19<br />

Valg af målepunkt for accelerometret...........................................................................................................................19<br />

Montering af accelerometret. ........................................................................................................................................20<br />

Miljøpåvirkninger. ........................................................................................................................................................22<br />

Generelt.....................................................................................................................................................................22<br />

Temperatur....................................................................................................................................................................23<br />

Kabelstøj. ......................................................................................................................................................................23<br />

Andre miljøpåvirkninger...............................................................................................................................................24<br />

Accelerometer kalibrering.............................................................................................................................................26<br />

Andre transducere. ........................................................................................................................................................27<br />

Grundlæggende teori.........................................................................................................................................................28<br />

Grundlæggende vibrationsteori.................................................................................................................................29<br />

Spids-, gennemsnits- og effektivværdier.......................................................................................................................32<br />

Almindeligt forekommende maskinfejl. ...........................................................................................................................35<br />

Ubalance. ......................................................................................................................................................................35<br />

Ubalance i maskiner med lodret akse........................................................................................................................36<br />

Ubalance i maskiner med overhængende leje ...........................................................................................................37<br />

Årsager til ubalance ..................................................................................................................................................37<br />

Graden af Ubalance...................................................................................................................................................37<br />

Opretningsfejl ...............................................................................................................................................................39<br />

Opretningsfejl............................................................................................................................................................39<br />

Vinkelfejl ..................................................................................................................................................................39<br />

Parallelfejl.................................................................................................................................................................39<br />

Almindelig opretningsfejl .........................................................................................................................................40<br />

Temperaturindvirkning på opretningen.....................................................................................................................40<br />

Fejlopretningens Vibrationsspektrum .......................................................................................................................40<br />

Årsager til opretningsfejl...........................................................................................................................................41<br />

Bøjet aksel.....................................................................................................................................................................42<br />

Symptomer................................................................................................................................................................42<br />

Roterende løsgang.....................................................................................................................................................43<br />

Stationær løsgang......................................................................................................................................................45<br />

Rulningslejer.................................................................................................................................................................45<br />

Non-synkrone toner...................................................................................................................................................46<br />

Typisk udvikling af lejeslid.......................................................................................................................................47<br />

Løsgang i rullekontaktlejer .......................................................................................................................................52<br />

Skæve rullekontaktlejer.............................................................................................................................................52<br />

Lejeproblemer i maskiner med flere aksler...............................................................................................................52<br />

Glidelejeproblemer........................................................................................................................................................53<br />

Typer af glidelejeproblemer......................................................................................................................................53<br />

Oliehvirvel ................................................................................................................................................................53<br />

Side 3 af 157

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