2x70watt ballasts- wiring problem

[london-electric]

Have a job in a school, premises manager has asked me if it possible to change the electronic ballasts in the lights (prob 200+) in the school as they go.
The lights are very old style thorlux twin 6ft, which over the years have been painted around ...and to be fair are very good fittings with all robust diffusers still in tact

I have grabbed a couple of 2x70w ballasts from BEW (my wholesaler ) , the problem I have is the wiring is completely different as shown in the 2 photos....firstly the fitting has 7 cables coming from the lamp wiring and the original ballast has 7 terminals (the transtar one), whereas the osram only has 6 terminals

I have been informed by a retired tv engineer (thought i'd ask him to take a look, re: electronics experience) , that on is series wiring and the other is paralell

Has anyone encountered this before, and could anybody help with this issue please

Any feedback, much obliged.

 

[Marvo]

Is the Osram ballast HF?

Are you just replacing the ballasts as they fail or are you replacing all together? Electronic ballasts have different wiring schemes depending on manufacturer, it doesn't necessarily mean they're series wired. You'll just have to make the necessary wiring changes according to the wiring diagram.

 

[ian.settle1]

Get a coil of white singles used in fluorescent fittings from your wholesaler and just rewire the fitting as per the drawing on the ballast rather than trying to use the existing wiring.

You'll find it cheaper though to totally replace the fitting rather than mess around trying to change the ballast.

 

[Lucien Nunes]

Unless you fall foul of the maximum cable length shown on the Osram schematic, I can't see the problem here. The Transtar ballast has separate heater outputs for the common end of the tubes while the Osram has series heaters. You simply need to join/insulate any leads in Transtar terminal 1 which is the common point, not needed for the Osram. If there are two leads in terminal 1 connect them in a suitable Wago, if the two tubes are joined at the holders with just one lead run back to the ballast then remove it and the job's a good'un.

1> join/insulate
2> 23
3> 24
4> 21
5> 22
6> 25
7> 26


E&OE due to blurry photos!

 

[telectrix]

or go LED

 

[london-electric]

Thanks for the replies

We are simply replacing the ballasts as they go, around 6/7 out at the moment of about 200 throughout the school.
The current fittings are an old school thorlux type, which i have seen in several schools before, they have a very robust diffuser, I think thorlux quoted a replacement once at around £180.
The site manager is happy to pay for my time, as changing the fittings will create a lot of disruption/ need for redecoration etc.

Lucien, thanks for the reply. I have one of the fittings in my stores at the moment, so I will try your solution see how I get on.

Thanks for the input guys.