Help wanted with em fittings please

[chocca]

Hi all, I'm working on some maintained
em lights at the moment and theyrr doing my head on grr! They work fine as ems on power failure. but won't strike when power is restored. then, randomly one or two will come back on over 24hourd or so . they're tridonic combi ballasts on single 49w tubes. I've swapped some for new ballasts but the problem persists. Any ideas?

 

[Paul.M]

Change the starter?

 

[stef]

Are the maintained or non maintained types?

 

[stef]

Are the maintained or non maintained types?

Sorry, misread, foget this one:19:

 

[chocca]

Change the starter?

Electronic ballast, no starters.

 

[tazz]

Check charging/change over circuit, the older ones used to use change over relays on the board were the relay contacts stick being in the engergised position

 

[Paul.M]

Electronic ballast, no starters.

Good point. I missed that lol.

 

[Kamikaze]

Have you checked there is sufficient voltage?

 

[chocca]

Have you checked there is sufficient voltage?

Yep, voltage is well within limits. I've seen this problem before over the years and never got to the bottom of it. Not too bad when there's only one or two but this is in the stairwell of a 30 storey building (68 fittings in all) and probably 25% of them are acting up. Makes you look a twonk when you've condemned the originals and the new ones are as bad...:sick:

 

[nickblake]

have you tried changing the lamps could well be faulty tube especially if they light up for a few seconds an go off

 

[tazz]

If the fittings work on battery/invertor then you can rule out tubes or lack of voltage.
Basics em fittings are just a basic invertor circuit run off a battery feeding the normal fitting. Battery is charged off mains voltage. If mains is lost invertor kicks in via relay or switching circuit. If the fitting works on battery then it tubes, ballest, starter etc are all ok.
It has to be the control circuit

 

[oldtimer]

Remember the batteries will start to decay after 5-7 years as no rechargeable battery does you get the same problems in fire and intruder alarm system so how to fix it simple replace the batteries if you are not sure buy 2 sets put themm into 2 lights leave it for a day or overnight.

Also good practice is to write the date on the battery and if you get a problem with a light then you can check the battery

 

[i=p/u]

but if it ha is happening with new fittings....

 

[tazz]

Oldtimer you are correct with nicads life, but as original post states the fittings are working ok on battery but not on mains supply

 

[sparkatus12]

Had a problem once where new fittings worked fine and switched correctly. However in emergency mode lamps only stayed on for a few seconds. Turned out when engineer came out the batteries were fitted with reverse polarity in the factory. (Killing the batteries.)

 

[tazz]

Had a problem once where new fittings worked fine and switched correctly. However in emergency mode lamps only stayed on for a few seconds. Turned out when engineer came out the batteries were fitted with reverse polarity in the factory. (Killing the batteries.)

I give up............!!!!!!!!!!!!!

 

[Guest111]

As Tazz has said it has to be on the control side,if the fittings are new then that rules out a problem with fittings as its unlikely they are all faulty,try testing for a voltage with something that puts a load on the circuit rather than a digital meter as the current drawn by a meter is very small and sometimes they will read say 240 v but when you put a load on the voltage disappears and it can be someting as simple as a loose connection but relying on the meter saying you have the correct voltage there you spend ages chasing your tail.

 

[Rampage]

Would it be easier to turn them all on then check the voltage?

 

[Merl]

Had a similar problem months ago with tridonic combo ballasts. Lamps would strike and stay lit on battery back-up, restore the mains and lamps would flash twice and stay off. Turned out to be faulty lamps.

Try new lamps as nick suggested in post #10 if you haven't already.

Keep us posted if you get to the bottom of it.

 

[chocca]

Well gentlemen, the problem has gone away for now but without me finding the solution...

In response to the voltage questions, the fittings that are faulting are on a circuit of 10 lights and only 2 or 3 are faulting - voltage is ok.

The batteries in some of the fittings are brand new - the original fault developed when I was changing the packs after they failed the 3 hour discharge test and I'd had the circuits turned off. As described above by Merl, they flashed twice on restart then wouldn't come back on.

When I got there yesterday most of them had come back to life.

Tried changing the lamps in the remainder to no avail and finally changed the ballasts again and the tinkers worked.

I've returned the ballasts to the supplier and asked to be informed if anythings found...