# fluorescent lighting capactior



## Ian_s114

I was wondering if anyone could tell me in a bit of detail why the supply current in a fluorescent lighting circuit is reduced when the capacitor is in circuit, i understand vaugly but would like a decent explanation thank you 
Ian


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## frank

Ian

The capacitor within a fluorescent fitting can have two or three uses - depending upon the type of fitting.

Without going in to detail you may find capacitors undertaking 3 functions within a fluorescent fitting. Some older fittings used capacitors as voltage droppers/discharge controllers. Some used them as interference suppressors. I think that you are probably talking about the standard ballast type utilising a motor starter unit. The capacitor here is used as a Power Correction device to change the inductive load cosine angle to a more efficient level. Something in the order of 0.95 for example. Why there is a current reduction when the capacitor is placed in circuit is explained by the above. The tube will use more energy as a result of the capacitor being removed from the circuit.

ie W=IV CosQ

Hope this helps, and non too vague


Frank


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## Trimix-leccy

frank said:


> Ian
> 
> The capacitor within a fluorescent fitting can have two or three uses - depending upon the type of fitting.
> 
> ....the standard ballast type utilising a motor starter unit.
> 
> Frank


*A motor starter unit!!!! *would that be a D.O.L. or Star Delta:laughing:....I though that was an expression used only by the great unwashed who are ignorant in the dark ways and mystical arts of elektrikery bestowed upon us by the Great Spark when we finished the City & Guilds


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## frank

I don't know why - but there it is. Drummed into me by old timers over many years of being clipped behind the ear and told to go stand in the corner and thread endless ends of conduit, and I still can't get it right. Starter motor - now that's better,

Frank


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## Trimix-leccy

frank said:


> I don't know why - but there it is. Drummed into me by old timers over many years of being clipped behind the ear and told to go stand in the corner and thread endless ends of conduit, and I still can't get it right. Starter motor - now that's better,
> 
> Frank


 
Ah! my attempt at sarcasm [maybe even irony?] has been lost.....:laughing:

I meant 'should it not be starter or starter switch ' and NOT Starter motor....because it isn't a motor
...or are you 'double bluffing' me:whistling2:, and the 'choke' is on me:jester:


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