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From http://www.harison-toshiba.com/lampinfo.htm: [Note that this ia a manufacturer of subminiature vacuum lamps.]
Since incandescent lamps may be rerated to suit various design goals, existing standard lamps should be reviewed prior to initiation of a new lamp design. Three basic formulas apply when rerating a lamp, assuming that VA equals application voltage and VD equals design voltage, the following may be applied: (M.S.C.P. represents Mean Spherical Candlepower) ![]() ![]() ![]() [Note that the first two formulas are very close to the formulas below (3.5~3.4 and 12~13). The differences may be attributed to the different lamp types being considered.] From Mike Wood, of Mike Wood Consulting. lumens/LUMENS = (VOLTS/volts)^3.4 life/LIFE = (VOLTS/volts)^13 (i.e. reduce the volts to 90% and the life increases by 393%!) EFFICIENCY/efficiency = (VOLTS/volts)^1.9 watts/WATTS = (volts/VOLTS)^1.6 (not 'squared' as you would get with a fixed resistance) coltemp/COLTEMP = (volts/VOLTS)^0.42 See also http://www.sylvaniaautocatalog.com/n...fila_lamps.htm. Copied from this post by ship. LIGHT OUTPUT CALCULATIONS a dinner candle provides about 12 lumens. A 60-watt Soft White incandescent lamp provides 840 lumens. Foot-candles = candela / distance in feet * distance in feet Foot-candles = Lux / 10.764 = lumens/sq. meter; 1 fc=1/10.764 lux Foot-candles * 10.764 = lumens/sq. meter = lux Lumens/sq. ft. * 1 = foot-candles; (1fc=1 lumen/ft²) Lumens/sq. ft. * 10.764 = lumens/sq. meter Lumens * 0.07958 = spherical candle power Lumens = Mean Spherical Candlepower x 12.57 Lux * 0.0929 = foot-candles Lux = candela / (distance in meters * distance in meters) Lambert * 0.3183 = candela/sq. cm [candela per sq. cm], Lambert * (1/pi) = candles/sq. cm Lambert * 295.720 = candela/ sq. ft. candela per sq. ft.] Lambert * 1 = lumens/sq. cm Illuminance (lx) = E = Luminous flux falling on area (lm) ÷ Illuminated area (m²) Illuminance (lx) = E = Luminous intensity (cd) ÷ [distance in meters (m)]² Luminance (cd/m²) = L = Luminous intensidy (cd) ÷ viewed luminous area (M²) Luminous efficacy (lm/w) = h = Generated luminous flux (lm) ÷ Electrical power consumed (w) Efficacy=F(lu)/P(w) F=Luminous Flux P=Electrical Power (wattage), in watts LIGHT BEAM CALCULATIONS: [See Convventional Photometrics_v6.zip for a down-loadable MS Excel workbook containing most popular fixtures.[FONT=Book Antiqua">/FONT]candela per sq. ft.] Lambert * 1 = lumens/sq. cm Illuminance (lx) = E = Luminous flux falling on area (lm) ÷ Illuminated area (m²) Illuminance (lx) = E = Luminous intensity (cd) ÷ [distance in meters (m)]² Luminance (cd/m²) = L = Luminous intensidy (cd) ÷ viewed luminous area (M²) Luminous efficacy (lm/w) = h = Generated luminous flux (lm) ÷ Electrical power consumed (w) Efficacy=F(lu)/P(w) F=Luminous Flux P=Electrical Power (wattage), in watts LIGHT BEAM CALCULATIONS: [See Convventional Photometrics_v6.zip for a down-loadable MS Excel workbook containing most popular fixtures.[FONT=Book Antiqua Beam diameter = distance * (2 * tan (beam angle in degrees / 2)) Throw distance = Square root [(horizontal dist. * horizontal dist.) + (vertical dist. * vertical dist.)] Inverse Square Law: E(fc)=I(cd)/D(ft)². E(fc)=F(lm)/A(ft)² A=Area in square feet D=Distance in feet E=Illumination in footcandles F=Luminous Flux in Lumens I=Luminous intensity (Candlepowe) in candles Mired Shift Value = (1,000,000/d) - (1,000,000/a); d=Desired Color Temperature (no units), a=Actual Color Temperature(no units) Fixture Lens Conversion Guide: For a two-lens system: EFL= (f1*f2)/(f1+f2-d), where EFL=Effective Focal Length, f1=Focal Length of Lens1, f2=Focal Length of Lens2, d=Distance between focal points of each lens. 50° - 3.5Q5 / 360Q-4.5x6.5 (45°) 40° - 3.5Q6 / 360Q-6x9 (37°) 30° - 3.5Q8 / 360Q-6x12 (27°) 20° - 3.5Q10 / 360Q-6x16 (17°) 10° / 12° - 3.5Q12 / 360Q-6x22 [single lens] (9.5°) 5° - None 8x8 (20°) 8x10 (16°) 8x16 (6°) 1Kw PAR64: VNSP (FFN)- Beam: 6° x 12° Field: 10° x 24° NSP (FFP)- Beam: 7° x 14° Field: 14° x 26° MFL (FFR)- Beam: 12° x 24° Field: 21° x 44° WFL (FFS)- Beam: 24° x 48° Field: 45° x 71° POWER CALCULATIONS Power = Voltage * current (Watts = Volts * Amps) P(w)=V(v)xI(a) P=Electrical Power (Wattage) in watts V=Voltage (EMF), in volts I=Electrical Current(Amperage), in amps Current = Power / Voltage (Amps = Watts / Volts) RMS Volts = 0.707 * Peak Volts RMS Volts = 1.11 * Average Volts Ohm’s Law: V(v)=I(a) * R(Ω) V=Voltage (EMF), in volts I=Electrical Current (Amperage), in amps R=Resistance, in ohms Impedance: Z(Ω)=√[R²(Ω)²=X²(Ω²] Z=Impedance, in ohms R=Resistance, in ohms X=Reactance, in ohms Power Factor: R(Ω)/Z(Ω) pf=Power Factor R=Resistance, in ohms Z=Reactance, in ohms DC VOLTAGE DROP OF CONDUCTOR (cable) OF L LENGTH V = voltage drop, I = current R = resistance of conductor per 1000 feet L = length of conductor in feet R for 18awg = 6.51, 16awg = 4.09, 14awg = 2.58 12awg = 1.62, 10awg = 1.02, 8awg = 0.64 V = I * L * (R / 1000) * 1.004
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