U S E R M A N U A L D A Y C O R ® S U P E R B
11
Inspection tips
Handling Non-Corona UV Background
Non-corona UV spots are characterized by their random manifestation.
Corona UV spots are characterized by their repetitive manifestation.
Sources of UV spots
•
Usually near substations in industrial areas there is a lot of “non corona”
UV background due to welding machines operating in factories and
construction sites, or fires due to flares of refineries, or other chemical
industries. In some locations lamps with very strong UV emission or mercury
lamps with inadequate UV protection are installed. Welding machines produce
thousand times more UV than corona. This yields random UV spots on the
display, and might give an inexperienced camera operator the feeling as if the
camera is not "solar blind". Although those random UV spots do not harm the
camera, it is recommended not to look for a long time directly on a welding
machine with the camera.
•
A strong UV source, even a strong corona, will always scatter UV photons.
This is a natural phenomenon occurring due to the short wavelength of UV,
and is not a problem of the camera.
•
In a substation with many strong corona sources, UV light scattering effects
will also cause a lot of random background.
How to recognize a corona source
You will still be able to recognize a corona source because
corona is repeating at the
same location while the background noise is random.
How to reduce the effect of non corona UV background
To reduce the effect of non corona random UV background:
•
Reduce the UV gain to a minimum value of 100 - 120
•
Activate the LI option and change its values until most spots disappear and
only the corona is noticeable
Chapter 3
3
