GE American Fluorescent Watt-Miser F90T17-CW-WM
This mogul size 2â…›-inch diameter 5-foot fluorescent lamp has a long history - the original version having been launched on 20th October 1940 as the ninth lamp in the American fluorescent series, consuming 100 Watts at 72V when driven at 1450mA. It was the first highly loaded lamp intended to take fluorescent technology into industrial lighting. To keep the voltage suitably low for operation on a simple choke ballast, it was necessary to scale the diameter up to this unusually large T-17 54mm tube.

As a result of its high loading it was not a terribly efficient lamp, and efforts were later invested in improving this. In 1948 GE launched an energy-saving 85W retrofit that delivered the same light output. It was the first fluorescent lamp to use a krypton fill, whose reduced volt drop lowered power and increased efficacy due to less energy loss in collisions between electrons and gas atoms. However it also made starting more difficult in cold atmospheres. By 1953 it had been replaced by a 90W lamp having a mixed krypton-argon fill, perhaps for easier starting.

The Watt-Miser lamp featured on this page consumes just 82W, and was first listed in the GE 1977 catalogue. It consumes 9% less power than the former F90T17, with only 4.5% drop in flux on laboratory reference ballasts (or 9% drop on typical CBM / Commercial Ballast Manufacturers' control gear). It is not certain if the power drop is achieved the same way as the 1948 lamp, by a full krypton gas filling - if yes, then to overcome starting difficulties, this lamp probably employs an internal transparent electrically conductive coating of fluorine-tin-oxide, as first introduced for GE's Watt-Miser 4ft T12 lamps in 1974.
Manufacturer: General Electric U.S.A.
Lamp Power: 82 Watts
Lamp Current: 1.50 Amps
Lamp Voltage: 61 Volts
Cap Type: G20 Aluminium
Bulb Type: T-54 T-17 in eighths/inch
Bulb Finish: Cool White 3Ca3(PO4)2.Ca(F,Cl)2:Sb,Mn
Electrodes: Triple-Coil + Anode Plates Triple Carbonate emitter
Discharge Length: 1372 mm 54 inches
Atmosphere: Hg | Kr+Ar?
Luminous Flux: 5,750 lm (@ 100h) 5,060 lm (mean)
Luminous Efficacy: 70.1 lm/W (@ 100h) 61.7 lm/W (mean)
Colour Temperature & CRI: CCT: 4150K CRI: Ra62
Chromaticity Co-ordinates: CCx: CCy:
Rated Lifetime: 9000 hours
Warm-up & Re-strike Time: 1 minute Instant
Burning Position: Universal
Nominal Length: 1524 mm 60 inches
Factory: Circleville OH U.S.A.
Date of Manufacture: January 1995
Original Value:
 
References: 1) Fluorescent and Other Gaseous Discharge Lamps, W.E.Forsythe & E.Q.Adams, publ. Murray-Hill Books, 1948, p.96
2) The Electric Lamp Industry, A.Bright, publ. Macmillan Books, 1949, pp.412 & 501
3) GE Magazine of Light Vol.17 No.3 1948 p.3
4) GE Advert for New 85W Krypton Fluorescent Lamp, Time Magazine, 1st November 1948 p.39
5) GE #9200 Lamp Catalog, USA, 1953, p.18
6) GE #9200 Lamp Catalog, USA, 1977, p.69
7) GE #9200 Lamp Catalog, USA, 1993, p.4-5
8) GE #9200 Lamp Catalog, USA, 1996, p.4-5