toasted capacitor 1

[colonelbogart]

Our plant uses a lot of metal halide lightings. 400 watts cooper. The lightings are installed inside the production area which temperatures varies from 4°C to 10°C with some on -18°C area. We are conducting a weekly shut off of the lightings as long as we can (other areas are not possible).

I noticed that we are encountering a perennial problem on capacitor (busted or toasted). Is it natural?

Need your comments Please

Thanks

Bogart

 

[itsmoked]

Busted? Do you mean ruptured like frozen? Some caps don't take well to freezing.. They are a chemical beast.

 

[jraef]

Are you refering to a cap inside of the MH ballasts? If so, itsmoked's comment is right on. Electrolitic capacitors cannot be energized if frozen, they will short and sometimes even explode. If you need to do this shutdown on a regular basis when the temp is below 0°C, you will need to install space heaters to warm up the ballast assemblies prior to applying power to them.

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Read the Eng-Tips Site Policies at faq731-376
Member, [blue]P[sup]3[/sup][/blue]

 

[resqcapt19]

jraef,

Are you refering to a cap inside of the MH ballasts? If so, itsmoked's comment is right on.

What do they use for outside MH fixtures in code climates? Outside lighting is not energized in the day time and the capacitor would freeze on cold days.
Don

 

[itsmoked]

resqcapt19; Good question. I went to the Cooper lighting site and picked a random industrial high bay asile MH HID pendant out of 100 different ones. It listed "starting down to -40C".

So they may not have caps in them or they may have special low temp caps. May be colonelbogart has non low temp fixtures now in a freezer. Perhaps he could locate low temp caps and sub them in as the regulars fail.

I would ask the maker.

 

[jraef]

Dry film caps designed specifically for cold environs. They are more expensive so indoor fixtures cost less, but may (should) have had a warning about avoiding freezing temperatures.

"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Read the Eng-Tips Site Policies at faq731-376
Member, [blue]P[sup]3[/sup][/blue]

 

[hottip]

Our plant is located in the desert, where temperatures bellow zero are not common. The temperature is between 5 and 45 °C and I've seen toasted capacitors for the same case that you are debating here.

 

[colonelbogart]

Hi there,

more details:

most of the busted caps, as in the caps bursts or swells, are coming from those installed on 4°C to 10°C temp. I dont remember toasted one from below zero areas. But since our company is intensifying its drive on energy conservation we did some 10 to 12 hours shutdown every sunday on these areas (-18°C)since two weeks ago.

thanks