Quick question

luke12345 · Jan 25, 2012

Hi there, I was wondering might anyone be able to answer a few of these questions that I cant find an answer:
- Firstly with switch start fluorescents do I use the 1.8 correcting factor when calculating the total load? Why is this?
- does the correction factor apply for digital ballasts as well?
- Does this correcting factor also apply for any other type of fitting such as SON / Metal Halide?

cheers

telectrix · Jan 25, 2012

all discharge lighting needs a current correction. the factor of 1.8 is sufficient for most types.

luke12345 · Jan 25, 2012

so it doesn't matter if the fitting has aa capacitor or not, all discharge fitting ( fluorescents, SONs, Metal Halide, PL lamps, 2D lamps ) need the 1.8 correction factor. Is that correct?

Crosswire · Jan 25, 2012

Unless otherwise specified in the manufacturers' spec.

Edd · Jan 25, 2012

discharge lighting is highly inductive and even though the lamps are rated in watts the whole unit should have a VA rating.
its this VA rating that the current is calculated.
if no VA rating is given then a value of 1.8 is used to calculate it from the wattage. so its watt x 1.8 = VA.
circuits can then be calculated from this

Deleted member 26818 · Jan 26, 2012

I thought with flourescent's, the factor was 1.5?

MarkieSparkie · Jan 26, 2012

Final circuits for discharge lighting must be capable of carrying the total steady state current, i.e. lamp current plus any associated control-gear current including their harmonic currents.
Where more accurate information is not available, the demand in VA is taken as the rated lamp W multiplied by =>1.8. The 1.8 multiplier assumes a power factor of not less than 0.85 lagging and takes account of the control-gear losses and harmonic current.