Is a 70W light actually 70W?

[SidTheSparky]

Does a 70W 6ft fluorescent batten fitting actually 'consume' 70W, or is it just the lamp which 'consumes' 70W with extra losses to be accounted for in the control gear (ie additional losses in the choke etc)?

Initial stages of looking at reducing energy bills for a warehouse. Old fluo battens to evaluate against more modern lighting solutions.

Thanks in advance for any quality feedback.

 

[Badger]

i thought it actually gave out 7watts worth of light brian!! :C

 

[Nicky Tesla]

Yes your correct sid 70w plus any heating losses in the c/gear which can be different in different fittings.

You have to take this into account when working out the running current as well as the start up current which is higher(x1.8)

To check your calculations take a current reading when a bank of lights are fit, but use the sites actual voltage and not just 230v.

 

[Evans Electric]

The tubes are 70W and the gear is extra , without makers detail X it by 1.8

Modern Fluorescent fittings are more energy efficient , HF even more and Triphosphor tubes are more efficient and more light output.

 

[SidTheSparky]

Quality answers, thanks.

This has prompted me to look at an old fitting which I took down from the site (I often go there to replace the odd few burnt-out fittings on a piecemeal basis).

The old fittings are Thorn with Tridonic ballasts stating "Lamp:0.70A".

This has also prompted me to think of IxV = 0.70 x 240 = 168W (neglecting power factor - that's another story - overall at the supply the power factor is 0.6 without the pfc capacitor switched on - it's an aged capacitor and I'm not brave enough to switch it on without further investigation into why it is switched off or its condition).

Applying the overall power factor I guess we're perhaps looking at 0.6 x 168 = 100.8W

My initial thoughts are to evaluate replacing the lamps with LED lamps which I believe can be done by cutting out all the control gear and just using the two lampholders on the original fittings direct onto mains voltage.

This I presume may also help to correct the power factor, due to reduction of inductive load.

I am not sure if they are currently paying a surcharge for bad power factor.

This is all presuming 240V but I reckon they'll have nearer 250V.

 

[Sidewinder]

Ou can get retrofit tubes that are LED and need just a starter change, they work with all the existing control gear in the fittings.

 

[SidTheSparky]

Ou can get retrofit tubes that are LED and need just a starter change, they work with all the existing control gear in the fittings.

So I guess that the retrofit LED lamp will consume way less than a fluorescent tube, along with significantly less losses in the ballast as it won't be handling so much current, hence it'll still help to reduce energy consumption? If so, then it all sounds good.

My only concern is that the ballasts are regularly beginning to fail due to age I think (along with some issues over starters). I don't want to be in a position where I retrofit some LED lamps only to find that the ballasts are still failing for whatever reason. Perhaps reduced current from LED lamps might alleviate ballast failures going forward but I'd need to be convinced.

 

[cadspark]

Leds don't need the ballast so just bypass it.

 

[kme]

I only have one issue with T5 / T8 LED tubes - they are horrendously expensive. I think it`ll take a few decades to pay for itself - even before you factor in the install costs!

 

[Evans Electric]

I wouldn't do anything with the lighting without the services of a lighting consultant or technical rep. TBH You could foul up big time .

I noticed last week in the B&Q at J9 of the M6, the lighting had been changed from high bay fittings to 4 lamp strip lights . I use the word "strip" because they basically rubbish regarding light output . They look like a fluorescent tube but dimmer , light levels in that part of the store were poor, if it was a factory floor , assembly shop they would be no good at all .

Although I mention HF fittings in post #4 my experience after fitting a load of them , different makes ,same gear, at a printing firm was that the control gear had a life of around 2 years .

When we did complete move for another printer we went back to switch start .

 

[SidTheSparky]

Thanks. I was going to get a lighting manufacturer's rep in anyway, but not at this early stage. Also I'd do a trial in one area beforehand.