electronic ballasts

[murdock]

here something i learnt yesterday...if you take a tube out of a light fitting which has an electronic ballast 4 ft or 5 ft double fittings it goes into a fault safe mode and will not work until you switch off the power and switch it back on...or some have a time delay which could be a couple of hours.

how many of you have removed the ballast and returned it to be replaced because it is still new...without knowing about this fall safe mode?

i have brand new electrocnic ballasts on my workbench as we speak which have been removed because i didnt know about this...i changed the tube without switching off the power and the light stopped working so i replaced the ballast and then they worked so now i will test these new ballast to make sure they are actually faulty.

[adrianh]

Manufacturer?
T5 T8?

[daveob]

Sounds like an opportunity for a dodgy electrician to replace your 'faulty' unit with a 'new' unit - the same 'new' unit that he took out the last unsuspecting customers light.

So he gets to charge for a new replacement every time without having to buy a new unit.

[upsinformant]

I have never heard of that, having worked with hundreds of ballasts when replacing them with low energy units for green purposes. Interesting though..

[murdock]

the ones i am refering to are standard 5ft double flu. fittings with electrocnic ballasts ..."make"... you would need to check with your lighting supplier as to which make reacts in what manner...i spoke to my supplier and he told me the same thing today and advised me he was aware of the problem so i asked him why he had not notified us of this issue before...because on numerous occassion i have just removed the whole fitting with the electronic ballast complete and replaced with the old standard fittings with a starter and wire wound ballast.

you live and learn.

[adrianh]

Interesting. We've used hundreds of T5 & T8 Tridonic, Osram & Philips electronic ballasts and I've never come across this. They have been shorted, cross connected, the V grips have failed, but I can't say I've ever had a problem. But then, as soon as we something wrong we turn the system off, check, correct and then turn the system back on. We never connect or disconnect tubes while the ballast is powered for fear of damage or electrocution.

[AndyD]

I've not come across this on standard electronic ballasts, only independently addressable, dimmable ballasts which are on DALI lighting systems. It was probably inevitable this trend would eventually extend to normal ballasts but like I say I haven't seen them yet in the commonly used fittings.

[bergie]

i got caught like that as well.i tend to install or replace tubes live.i have found many fittings (36+58 watt electronic ballasts,different makes ) that you have to switch off and on again to get it to work. i havent noticed long reset periods though.

[adrianh]

Now why would you install or replace tubes live? Like changing a cars spark plug on the move!

[murdock]

i always do it live and if the fitting has a starter which clips in from the side i change it at the same time even if it works...like the geyser thermostat...while repairing replacing the element just replace the thermostat at the same time...

the only time i switch off the power is when i open the cover...to replace components inside the fitting.

i havent personally had the time delay either i heard this from someone else who experienced it...a maintenance person in a factory with plenty of 5 ft fittings...you can believe it not...i have a ballast i replaced recently and am gona run some tests on it.

i have stopped installing fittings with electronic ballasts due to their quick failure....this could have been due to the make supplied bt the wholesaler.

[adrianh]

Fair enough, I can see why you would install them live. We predominantly use Tridonic T8 Top and I haven't had serious problems with them. Now here is an interesting one. We use T5 UV tubes in one of our products. The Tridonic T5 Pro doesn't seem to be powerful enough to keep them going. Another thing we found was if you have lots of T5 Pros in a circuit strange things happen. Some of them refuse to start. The T5 UV tubes are quite happy with T8 Tops though.

[murdock]

you talk of uv lamps the reason why you use them?

[adrianh]

The lamps are installed inside the canopy of a kitchen air extraction system. Oil & odours are converted into H2O & CO2 because the UV generates massive amounts of Ozone. Bacteria is also killed beause of the frequency of the UV light.

You sure don't want to work on them when they are live, you get your face burnt & arc eyes. Made this mistake a couple of times.

[AndyD]

The T5 UV tubes are quite happy with T8 Tops though.

Ballasting a T5 tube with a T8 ballast can cause problems although I'm guessing some of the more intelligent ballasts may automatically adjust their output accordingly. The T5 range are all different lengths than the T8/T12 ranges to stop them accidentally being substituted for each other.