BENCHTESTS
Has the Cosmo met its match?

GE has introduced a competitor to Philips’ highly successful Cosmopolis lamp, the category killer in white streetlighting. But how does it compare? We gave it Lux magazine’s famous benchtest. Ray Molony reports

With its white light, high efficiency, long life, good colour rendering and dimmability, it’s easy to see why Philips’ Cosmopolis lamp has been such a huge hit with local authority lighting engineers. It ticks every box going, and then some.

Streetwise lampThe benefits of white light from ceramic metal halide lamps in the public realm are legion. For a start, you can deliver less output under the codes – because people’s perception with white is better, you can use less.

Not surprisingly, it’s been a huge success for the Dutch giant. And, apart from a licensing deal with Sylvania, the lamp has had no serious competitors. Until now, that is.

It’s been an open secret that GE’s boffins in Budapest have been working on an alternative. Considering the Cosmo – as it’s known – was introduced back in 2005, it’s taken GE some time to unveil its version. But it looks like it’s been worth the wait.

And with standard HPS set to be phased out under energy-using products regulations, more alternatives to SON are needed.

The StreetWise lamp is, crucially, a retrofit and will run on most existing high-pressure sodium gear. The Philips Cosmopolis, by contrast, uses the proprietary PGZ12 base, and requires the dedicated Cosmo gear. The StreetWise cuts energy costs by up to 40 per cent compared with high-pressure sodium. And, like the Cosmo, it can be dimmed to 65 per cent power with negligible impact on performance.

Impressive result

All CMH StreetWise lamps provide 80 per cent lumen maintenance at 12,000 hours – the same as the Cosmo. The StreetWise range is available in 50, 70, 100 and 150W, with standard E27/E40 bases and the lamps will operate on both electronic and electromagnetic ballasts.

One can’t do a direct comparison with Cosmopolis because Philips doesn’t have a 70W version, but its 60W CosmoWhite 728 delivers a rated output of 6,850 lumens, says the company, which compares with the 8,067 lumens we measured from the 70W StreetWise in test conditions. We measured an average system efficacy across three lamps of 90 lumens per watt – an impressive result with this technology.

Streetwise test results

The market test

But the real test will be in the market, and with GE’s commercial and pricing policy. When it introduced its CMH competitor to Philips’ CDM ceramic metal halide lamp – a huge success in the retail sector – the quality of the lamp and competitive pricing meant it put Philips under pressure. The worry for Philips must be that it could do the same in the street lighting sector.

A welcome competitor to Philips’ Cosmopolis in the white streetlighting category, the StreetWise is a true retrofit to HPS. Make no mistake, this is a quality piece of lamp engineering and in the key metrics that we measured – efficacy especially – it delivered. Ninety lumens per watt in white light in strict test conditions is, in anyone’s book, a class act. Expect it to make inroads into Philips’ dominance of the sector.

HOW WE DID THE TESTS

The benchtest took place at Lux’s official test house, the highly respected laboratories of 42 Partners in Wolverhampton. The tests were conducted in a 3.5- metre integrating sphere (one of the largest in the UK) in accordance with EN13032 at 250C.

Three samples of the lamp were provided for the test, and were given 100 hours of pre-conditioning. No control gear was provided for the test, so we used a Philips BSN70L34 with a voltage of 240V and current output of 0.98A with a ballast power factor of 0.4.

42 Partners
21 Woden Road
Wolverhampton
WV10 0AU UK
Tel: +44 (0) 1902 453650
richard@42partners.com
ian@42partners.com

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