Self-Ballasted Electrodeless Induction Lamp

This advanced prototype is the predecessor of what was eventually launched for sale by GE in the form of its Genura electrodeless lamp. The initial developments concentrated on this traditional pear shaped bulb, but towards the end of the project it was decided to switch attention to reflector shaped versions. This was done because the sale price of Genura would be high, and it would be easier to sell into the high-value reflector lamp market than trying to take GLS market share. It is for similar reasons that the Philips XL and CQL GLS-retrofit induction lamps of the 90s were not sold.

This product is a 23-watt source and is the fruit of many years research carried out by Thorn on electrodeless lamps. Thorn had succeeded in building these light sources many years earlier, but it was not until the GE takeover that the research team could benefit from GE's expertise in electronics, and a self-ballasted unit could be produced.

The lamp operates at a frequency of 2.65MHz, similar to the Philips QL for optimal efficacy and at a wavelength which does not interfere with domestic equipment. The discharge vessel has a re-entrant stem running up the centre, and a ferrite coil with a few turns of wire is located inside this stem but outside the lamp atmosphere. The mercury amalgam dose resides inside a long exhaust tube running down the length of the stem. An emitter coating is applied to the glass re-entrant while the bulb is internally coated with fluorescent phosphor and a special anti-blackening pre-coat of gamma alumina. By the induction principal, the electronic 'ballast' drives the ferrite-cored coil at high frequency and this leads to ionisation in the discharge vessel. The inside of the bulb has a conductive fluorine-tin-oxide film to screen EM radiation.
Manufacturer: GE-Thorn Lamps Ltd
Lamp Power: 23 Watts
Lamp Current: 0.21 Amps
Lamp Voltage: 220-240 Volts
Operating Frequency: 2.65 Megahertz
Cap: E27s/27 (Nickel plated brass)
Bulb Finish: FTO semiconductor film Colour 830 phosphor
Bulb Type: PS-80
Overall Length: 175 mm
Mass: 200 grams
Atmosphere: Ar | Hg-amalgam
Luminous Flux: 1,400 lm (at 100 hrs) 1,150 lm (at 2,000 hrs)
Luminous Efficacy: 60.9 lm/W (at 100 hrs) 50.0 lm/W(at 2,000 hrs)
Colour Temperature & CRI: CCT: 3000K CRI: Ra 82
Chromaticity Co-ordinates: CCx: 0.440 CCy: 0.405
Burning Position: Universal
Rated Life: 10,000 hours (to 50% survival)
Warm Up / Re-strike Time: 15 secs (to 80% lumens) Instantaneous
Factory: Enfield and Leicester United Kingdom
Date of Manufacture: 1991
Original / Present Value: N/A
References: 1) Lamp Measurements.