Coronavirus sterilization - Nominal 60V UV fluo tube supplied on a 220V source

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Thread Starter

Matdg

Joined May 1, 2020
4
Hello there! I need your help.
I was trying to sterilize my mask against the coronavirus using an old UV fluo tube I had for another application. I could use this UV lamp on a 220V mains with a 22W ballast. This was working good (well I mean the lamp was lit ) but when I check the datasheet I realised that the nominal voltage of this lamp was 60V ! How come this is working without any problem on a 220V supply? What about the efficiency of the UV produced with this 220V when the nominal voltage should be 60V?

Cheers,
Mat
 

dl324

Joined Mar 30, 2015
10,718
Welcome to AAC!
I could use this UV lamp on a 220V mains with a 22W ballast.
UV isn't human friendly. You risk blindness and skin cancer.

Why not just hang your mask by a window and let sunlight disinfect it? That's what I do with the mask my Wife made for me. According to medical people, the virus can't live for more than a few days on cloth, so doing nothing could be just as effective (I only go out a couple times a month).
 

Thread Starter

Matdg

Joined May 1, 2020
4
Thank you for your concerns, but could you please answer the question and not trying to propose another solution.

What does a 56V nominal voltage means when using it with a 220V mains seems to work?

Cheers
 

LesJones

Joined Jan 8, 2017
2,638
56 volts will be the voltage between the ends of the tube WHEN IT IS BEING POWERED BY A BALLAST THAT CONTROLS THE CURRENT TO THE RATED CURRENT OF THE TUBE. If the ballast is rated for the same wattage visible light tube with the same dimensions then it should work. There are different types of UV tube that produce different wavelengths that are used for different purposes. The type you need is a germicidal tube. (I can't remember the wavelength but you should be able to find out using Google.) As others have said UV can damage your eyes quickly and cause skin cancer. Build it into a box with a lid switch so it can only be switched on when the lid is closed.

Les.
 

Thread Starter

Matdg

Joined May 1, 2020
4
Thanks a lot, I know about the dangerous effect of germicide UV (which wavelenght by the way is 254nm, in the UV-C range spectrum), I plan to use it in a closet, so There will be no side effect concerning skin or eyes damage.

I have another question, I am using a magnetic ballast ranging from 18W to 24W with a 24W UV lamp, is there other characteristics to be aware of ? I have read that there is a ballast factor to optimize the quantiity of light produced by the tube. If I understood well, this is a problem of impendace matching. I am wondering if using a condensor at the entrance of the ballast could increase the efficiency of the radiation power produced by the UV tube? What do you think?

Cheers

56 volts will be the voltage between the ends of the tube WHEN IT IS BEING POWERED BY A BALLAST THAT CONTROLS THE CURRENT TO THE RATED CURRENT OF THE TUBE. If the ballast is rated for the same wattage visible light tube with the same dimensions then it should work. There are different types of UV tube that produce different wavelengths that are used for different purposes. The type you need is a germicidal tube. (I can't remember the wavelength but you should be able to find out using Google.) As others have said UV can damage your eyes quickly and cause skin cancer. Build it into a box with a lid switch so it can only be switched on when the lid is closed.

Les.
 

LesJones

Joined Jan 8, 2017
2,638
Do not put a capacitor in series with the inductive ballast. Depending on it's value it can increase or decrease the reactance of the ballast. The worst case it if it forms a series resonant circuit at you mains supply frequency. In that case the only thing limiting the current would be the DC resistance of the wire in the ballast. The capacitors you have probably seen in fluorescent fittings are just for power factor correction. Domestic consumers (In the UK) are not charged for reactive KVA. I think The ballast that you have will probably be OK with your UV tube. In your post #4 I thought you were talking about connecting the tube to the mains directly without any for of ballast.

Les.
 
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