I am not a power supply designer - but all of the people in this lab are ->
so guilt by association.
Do not know of any commercial LED drivers that use linear converters, so you
are probably stuck with SMPS noise. I made a linear driver for cactus LED
array for a xmas decoration - but had to caref
V.IEEE.ORG
Subject: Re: [PSES] LED Chamber Lighting - drivers outside the chamber
In message
,
dated Fri, 1 Mar 2013, don_borow...@selinc.com writes:
>John is right. You want to feed LEDs a constant current, and let them
>drop whatever voltage they need. If I am not mistaken, LEDs have a
&
If the multi-string controllers are switched-mode, then we have the RFI
problem again.
Or, can the switching frequency be set to 500 Hz, so the 10th harmonic
becomes 5 kHz which is below 9 kHz ?
twisting the wires will also help for the frequency range 9 kHz to 30 MHz.
Rene Charton
I dimly remember the LED forward voltage voltage varies with temperature.
I think you definitely will need a currrent source.
I think the LEDs must all be connected in series.
Do you have LEDs that can carry 3 Amps?
2 serial strings in parallel should also be possible, but then the LEDs
must be
In my post, "luminary" started out "luminaire." But spell check "fixed" it
for me. Should have been more vigilant.
Ken Javor
Phone: (256) 650-5261
> From: John Woodgate
> Date: Fri, 1 Mar 2013 18:33:09 +
> To:
> Subject: Re: LED Chamber Lighting - drivers outside the chamber
>
> In me
Most mondo very mucho correct about string current imbalance. Look at
reference designs by TI and others that use multi-string controllers.
Brian
-Original Message-
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of John
Woodgate
Sent: Friday, March 01, 2013 10:33 AM
To: EMC-P
Conflict Alert - my employer makes LED drivers and LED array systems for
commercial stuff.
Heed Mr Woodgate - you must have CC source. TI and others make some nice LED
driver controller ICs. Look at their app notes. You have do the tradeoffs
correctly, or you will have a illumnation system with LE
In message ,
dated Fri, 1 Mar 2013, "ce-test, qualified testing bv - Gert Gremmen"
writes:
I know the topics about LED current sourcing and temp coefficient, but
as my power source is limited at 3 amps, which also is the full load
current of the LEDs, there is no risk of dead LEDS due to te
I know the topics about LED current sourcing and
temp coefficient, but as my power source is limited
at 3 amps, which also is the full load current of
the LEDs, there is no risk of dead LEDS due to temp runaway.
There are 10 LEDS in series and 10 of these chains in parallel.
http://www.ebay.co
In message
,
dated Fri, 1 Mar 2013, don_borow...@selinc.com writes:
John is right. You want to feed LEDs a constant current, and let them
drop whatever voltage they need. If I am not mistaken, LEDs have a
negative voltage temperature coefficient. With this being the case,
feeding a constant
John is right. You want to feed LEDs a constant current, and let them drop
whatever voltage they need. If I am not mistaken, LEDs have a negative
voltage temperature coefficient. With this being the case, feeding a
constant voltage will cause the current to increase as the diodes warm up.
The a
A long time ago I responded on this topic (maybe another thread) that the
way to do this is have the luminary itself and all wiring outside the
chamber; that guarantees no rfi from the lighting system. The way this is
done is using a light pipe installed through a stuffing tube to introduce
the lig
In message ,
dated Fri, 1 Mar 2013, "ce-test, qualified testing bv - Gert Gremmen"
writes:
I will try using a voltage stabilizer first.
If the terminal voltage varies much with temperature a current driver
approach may be necessary.
I strongly advise you to use a current source.
--
OOO - O
I am building some new 4 x 100 Watt LED
luminaires supplied by 35 Volts DC @ 3 Amps.
I'll LED you know my experiences in a few weeks
I will try using a voltage stabilizer first.
If the terminal voltage varies much with temperature
a current driver approach may be necessary.
These 10x10 LEDS
You need a constant-current source; how about an adjustable 3 terminal
regulator set up as one?
Cortland Richmond
On 3/1/2013 0900, Rene Charton/Twn/TUV wrote:
...ideas to generate a clean DC current?
-
This message is from t
Has anyone tried the following:
- disassemble the LED lamps and separate the LED portion from the Driver
Portion
- put a filter at the point of entry into the chamber
- Have the LED portion in the chamber, and the driver circuits outside the
chamber.
==
second try:
- op
g any
sort of overall product measurement I simply turn off the lights and close the
door.
So much for stating the obvious.
Gary
-Original Message-
From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, February 04, 2013 10:39 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES]
My employer makes LED lighting assemblies and drivers for custom industrial
market. They do, in fact, make some amount noise. The only super-quiet LED
illum would be if the power driver is located external to chamber and DC
power feed is filtered; or if the LED driver is a linear DC device.
LED ar
>Sent: Feb 4, 2013 1:22 PM
>To: EMC-PSTC@LISTSERV.IEEE.ORG
>Subject: [PSES] LED Chamber Lighting
>
>Has anyone tried out LED Lighting in EMC test chambers? If so, can you share
>your experience, opinions, likes and dislikes, and cost?
>
>I have recently seen several ads for LE
ny of them.
Nic Johnson
-Original Message-
From: Kunde, Brian [mailto:brian_ku...@lecotc.com]
Sent: Monday, February 04, 2013 12:22 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: [PSES] LED Chamber Lighting
Has anyone tried out LED Lighting in EMC test chambers? If so, can you share
lights and close the
door.
So much for stating the obvious.
Gary
-Original Message-
From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, February 04, 2013 10:39 AM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LED Chamber Lighting
I saw an amazing display of LED s
Hi Brian,
I've tested a variety of "60 to 100 W equivalent" CFL and LED lamps. They all
have SMPSs built in to their bases with a varying quality of filtering. While
most of the lamps are made in China, in general the U.S. brands are not too bad
for RE or CE, however, I'd stay away from the off
David Schaefer
-Original Message-
From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Monday, February 04, 2013 12:39 PM
To: EMC-PSTC@LISTSERV.IEEE.ORG
Subject: Re: [PSES] LED Chamber Lighting
I saw an amazing display of LED shield room lightning. The LEDs (and more
importantly)
r [mailto:ken.ja...@emccompliance.com]
> Sent: Monday, February 04, 2013 12:39 PM
> To: EMC-PSTC@LISTSERV.IEEE.ORG
> Subject: Re: [PSES] LED Chamber Lighting
>
> I saw an amazing display of LED shield room lightning. The LEDs (and more
> importantly) all the wiring, are totally ou
I saw an amazing display of LED shield room lightning. The LEDs (and more
importantly) all the wiring, are totally outside the chamber. A light pipe
penetrates the chamber ceiling at regular intervals through a stuffing tube
(waveguide beyond cut off).
It should be noted that this chamber has whit
Has anyone tried out LED Lighting in EMC test chambers? If so, can you share
your experience, opinions, likes and dislikes, and cost?
I have recently seen several ads for LED Light Fixtures and replacement kits
where a 100watt LED light can replace a 400 watt Metal Halide bulb or fixture.
But I
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