We just had our metal halide light fixtures replaced with LED fixtures in our 
large 10 meter Semi Anechoic Chamber and they are GREAT!!!  I have requested 
the Make and Model Number information from our Maintenance Department which 
I'll pass on when I get it. This is a holiday weekend for us so most are on 
vacation right now.

Anyway, every two to three years we had to have our metal halide bulbs changed 
because they would start arcing and messing up our Radiated Emissions results. 
We have a local rep. for All-Phase Electric who helps our maintenance 
department choose new energy saving light fixture technologies for our company. 
The rep. would bring in samples of the newest light fixtures and we would test 
them in our chamber for Emissions. Most were absolutely terrible due to noise 
from the internal switching power supplies. So I didn't have much hope when he 
dropped off the latest sample of an LED array light fixture for us to try out 
this past summer.

It was amazing!! Initially, we only picked up a little hump between 100Mhz and 
200Mhz where our noise floor is the lowest. The LED Light has an interface 
(about 2ft of wire coming out of a strain relief) for a Dimming Feature which 
we are not going to use. This pigtail wire was radiating a little and a little 
was coming off the power cord. So the Dimmer pigtail can be cut off if not 
needed or I just bundled it real short and put a cable tie around it.  I also 
put two snap-on ferrite beads on the power cord and all detectible emissions 
were gone.  Simple fixes.

I took the new LED fixture apart and found it be well built and well shielded. 
Inside, I found a MeanWell power supply completely encased in a metal chassis. 
I think the fixture is waterproof and could be used outside.  In any case, I 
was impressed.

When we installed the new lights, I had the two farthest from the antenna 
installed first. Then we ran a baseline and all we saw was noise-floor. Then we 
installed the remaining six with the same results. I was concerned about the 
fixture that is directly over the antenna which gets close when raised to 4 
meter off the floor, but again, nothing but noise floor.

Needless to say we have been very happy with these new lights. The only issue 
is that LED lights are very directional and shines mostly straight down. On one 
half of our chamber where the light fixtures are mounted a little farther 
apart, there is a shadow on the floor right in the down the middle, which is no 
big deal.

Like I said, when I get the model information, I'll pass it on.

Happy Holidays and God Bless.

The Other Brian

-----Original Message-----
From: Price, Andrew (Leonardo, UK) [mailto:andrew.p.pr...@leonardocompany.com]
Sent: Wednesday, November 22, 2017 7:01 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] Use of LED Spots in EMC Chambers [General Use]

Hi all.

Has anyone had experience with using LED Spot lamps in EMC Chambers?
What types/manufacturers would be recommended?

Would appreciate help in trying to solve someone's problems with noise during 
radiated emissions.
Test Facility has just had all their chambers converted to LED Spots and they 
are suffering broadband noise issues.

Regards
Andy




         Andrew Price
             Land & Naval Defence Electronics Division
             Prinicpal Environmental Engineer (EMC)

             Leonardo MW Ltd
             Sigma House, Christopher Martin Rd, Basildon SS14 3EL, UK
             Tel  EMC LAB : +44 (0)1268 883308
             Mobile: +44 (0)7507 854888
             
andrew.p.pr...@leonardocompany.com<mailto:andrew.p.pr...@leonardocompany.com>
             leonardocomapany.com
HELICOPTERS / AERONAUTICS / ELECTRONICS, DEFENCE AND SECURITY SYSTEMS / SPACE

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