Publicerad: 18 mars 2014
Kategori: Elseminarium
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Qualitative inspection
Expertpanelen för mätteknik
Voltimum
Qualitative inspection
Publicerad: 18 mars 2014 · Kategori: Elseminarium
Expertpanelen för mätteknik
Ur dokumentet
Electrical equipment Qualitative inspection with Thermal Imagers The electromagnetic spectrum Thermography Introduction What is infrared radiation ? • Infrared cannot be seen (but can be sensed by our skin) Visual Image • Everything emits infrared radiation • A camera converts the “infrared image” to a visible picture • Infrared allows you to “see” things that you normally can’t. Same image in IR Radiation and Temperature • Visual image is reflected ,thermal image is emitted! • Radiation increases with temperature 30 seconds in a microwave and New image new information Important to know: • We are only measuring the SURFACE: Plexiglas covers need be removed, doors need to be open • Emissivity: shiny surfaces will be hotter than their apparent temperature • Wind can also affect the measurement (Wind chill factor): so you should take into account convective cooling in or outdoors 5 Benefits of using IR technology • Measurements are: – Non-contact from safe distance – Obtained without disturbing production – Very sensitive to problem characteristics – Detect defects before significant problem – Can scan large areas quickly – Identifies specific locations 6 Limitations of using IR technology • Good Qualitative Measurements mean: – Safe distance- if needed use a tele lens to obtain the desired resolution – Inspected equipment should have enough load- minimum 40% of nominal load – In the case of faulty connections, the load has a very big influence on the fault’s temperature. – Be...
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