Lamp rerating

Lamp rerating is modelling the predicted properties of a filament lamp when running the lamp at a voltage other than its specified rating, using a power law function of voltage. The following equations can be used to estimate the new operating point. The exact value of the exponent parameters will typically vary slightly with the particular lamp design.

:V_a = Applied voltage

:V_d = Design voltage

• Rerated current = (V_a/V_d)^0.55 × current at design voltage {{cite web| title=Miniature halogen lamps; lamp electrical characteristics| author=Welch Allyn| year=2007| url=http://www.welchallyn.com/documents/Lighting/OEM_Halogen_Lighting/MC3544HPX_Catalog_2_11_09.pdf| accessdate=2011-09-06| archive-url=https://web.archive.org/web/20120325214506/http://www.welchallyn.com/documents/Lighting/OEM_Halogen_Lighting/MC3544HPX_Catalog_2_11_09.pdf| archive-date=2012-03-25| url-status=dead}}
• Rerated luminous intensity = (V_a/V_d)^{3.4 to 3.5} × Luminous intensity at design voltage {{cite book | last=Fink | first=Donald G. | authorlink = Donald G. Fink |author2=H. Wayne Beaty | title = Standard Handbook for Electrical Engineers, Eleventh Edition|publisher=McGraw-Hill |location=New York |year=1978 |isbn=0-07-020974-X |pages=22–8}}
• Rerated life = (V_a/V_d)^{−12 to -16} × Life at design voltage
• Rerated electrical power = (V_a/V_d)^1.6 × Electrical power at design voltage
• Rerated color temperature = (V_a/V_d)^0.42 × Color temperature at design voltage