Our Voltimum Experts answer your questions on a daily basis in our Technical Expertise area. This one, concerning lighting control gear and power factor values, is answered by Cooper Lighting and Safety:
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| PF is around 0.97 for HF control gear. |
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Question: Where would I obtain power factor (PF) figures? Do manufacturer's instructions contain information regarding PF figures to be applied for calculation purposes (eg: cable selection calculations for say, a lighting circuit)? Also, in relation for discharge lighting, Appendix 1 of the On-Site guide (17th Edition BS7671:2008) states: 'Where exact information is not available, the demand in volt-amperes is taken as the rated lamp watts multiplied by not less than 1.8. This multiplier is based upon the assumption that the circuit is corrected to a power factor of not less than 0.85 lagging, and takes into account control gear losses and harmonic current'.
Is this 1.8 figure acceptable by manufacturers, assuming that the appropriate technical information is not available?
Answer: Most manufactures publish this data, as do control gear manufacturers. Typically, the figures are 0.87 for discharge magnetic circuits and around 0.97 for high frequency (HF) control gear.
To see many more Q & A in Voltimum UK's Experts Area, please click on the link: www.voltimum.co.uk/consult.php?universe=consult.index.questions
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