I have some fluorescent fixtures with Philips ballasts and tubes in series.

 

The wiring diagram on the ballast shows a series capacitor but none of my fixtures have any capacitors.

 

Is there any reason I should add capacitors and if so what capacitance would make sense?

 

And yes, this is temporary as LEDs are the future.

 

Note uploaded images.

That capacitor is in parallel with the supply and is used for power factor correction, ie that the voltage and current are in phase so that the electric meter records the power correctly. 

 

What you are referring to as capacitors is commonly known as the starter for the lamp.

3 minutes ago, ubonjoe said:

 

What you are referring to as capacitors is commonly known as the starter for the lamp.

if you look at the picture of the ballast unit you can see it's a capacitor, must not need a starter.

The tubes are in series so you have half the voltage and need 110v starters. The S2 must be special for this purpose. 

 

As already mentioned, capacitor in diagram is for power factor correction.

Note that the capacitor is dotted  meaning it's optional. It's there for power factor correction but really makes no odds in a domestic environment. In a factory with hundreds of fittings it's another matter.

 

By the way, a poor power factor won't make your meter read incorrectly. 

FYI - in the wiring diagram it shows two starters (S) and one capacitor (C). I was not referring to the same thing.

 

Luckily I have now stocked up on starters that work on tubes in series. By the time I run out I should have completed my LED conversion.

 

Thanks for the info about power factor correction and especially for pointing out the dotted lines in the diagram. I completely missed that.

The Phillips S2 starter is designed for the lower wattage lamps. 4-22 Watts it gives you a better/faster start. The S10 starter range is 4-65 watts and it preforms better in the high range eg 36 Watts. The diag shows 2x18 Watt lamps on a 36 Watt ballast and normal starters.


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That's what I have, 2x18 W tubes on the 36 W ballast wired as in the diagram, and only the S2 starters work.