Fluorescent lights ??

[RickT]

I need to get some fluorescent lamps for the garage. As I use the garage as my workshop, I want it
to be as bright as possible.

Looking at the ScrewFix site, I see that the low power factor lamps only use 38W tubes, and the high
power factor lamps use 58W tubes.

The difference in price is negligible.

Going back (longer than I care to remember) to trade school days....

A fluorescent light needs a power factor correction capacitor in order for the power used by that
lamp to register on the electricity meter.

As I understand it...
All domestic fluorescent lamps do not need a PF capacitor, but they are limited to low power tubes.
All commercial fluorescent lamps need a PF capacitor, and can use higher output tubes.

Now the question..

If I get the HPF fittings, and remove the capacitor, is there any reason why it should not work as a
low power factor fitting i.e. not register on the meter.

Rick...

 

[CHJ]

No can do, lamp output will be degraded and you will still be consuming unproductive power. (electricity meter works on watts (VoltsXAmps))

The capacitor is used to re-align the voltage sine-wave peak with the current sine-wave peak to maximise the power curve.
This mis-alignment occurs because of the inductive choke that is used to limit the current flow through the ionised tube gasses.

 

[RickT]

Bear with me will you please, It's been a loooong time....

I seem to remember being taught that the way the lamp works is that when the starter activates, the choke generates a high striking voltage due to the collapsing magnetic fields, which activates the tube. Once the tube has been struck, it is self sustaining.

For the meter to register the power being used, both the voltage and current need to be in phase. Thus the need for the power factor correction capacitor.

I have seen lamp fittings both with and without capacitors. I thought that I had read somewhere about domestic fittings not needing capacitors because the power they use is so negligible.

Of course, I might be completely wrong, which is why I asked the question in the first place.

 

[CHJ]

http://hyperphysics.phy-astr.gsu.edu/hb ... owfac.html

http://www.cip.ukcentre.com/Power%20Factor.htm

http://www.ibiblio.org/obp/electricCirc ... AC_11.html

 

[RickT]

Ok, Thanks :shock:


Me Bad


Rick...