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Using electronic transformers with LED MR16 down-lights
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Tony
Mar 5, 2014, 1:23:00 AM3/5/14
to
Replacing the old halogen MR16 bulbs, I have no problems with the iron
core transformers.
However, with the electronic ones (mine are Nelson MTECOUGAR60), which
appear to be just small SMPSs, there is some uncertainty, as they have a
power range of 20 to 60 VA.
So what happens when they drive only 5W? I tried it and it still works.
No flickering, no dead LEDs.
But what are the general implications of having not enough load on an
"electronic transformer"?
Can it cause damage to the LEDs lights or the SMPS electronics?
How about the losses, bad efficiency with only 5W drawn?
Has anyone schematics I could look at?
Who's done it before? What's your experience?
What other (affordable) options are there?
Your input much appreciated.
Tony
core transformers.
However, with the electronic ones (mine are Nelson MTECOUGAR60), which
appear to be just small SMPSs, there is some uncertainty, as they have a
power range of 20 to 60 VA.
So what happens when they drive only 5W? I tried it and it still works.
No flickering, no dead LEDs.
But what are the general implications of having not enough load on an
"electronic transformer"?
Can it cause damage to the LEDs lights or the SMPS electronics?
How about the losses, bad efficiency with only 5W drawn?
Has anyone schematics I could look at?
Who's done it before? What's your experience?
What other (affordable) options are there?
Your input much appreciated.
Tony
Phil Allison
Mar 5, 2014, 2:16:02 AM3/5/14
to
"Tony"
>
> Replacing the old halogen MR16 bulbs, I have no problems with the iron
> core transformers.
> However, with the electronic ones (mine are Nelson MTECOUGAR60), which
> appear to be just small SMPSs, there is some uncertainty, as they have a
> power range of 20 to 60 VA.
> So what happens when they drive only 5W? I tried it and it still works. No
> flickering, no dead LEDs.
** Who said you could use them with LEDs ??
> Replacing the old halogen MR16 bulbs, I have no problems with the iron
> core transformers.
> However, with the electronic ones (mine are Nelson MTECOUGAR60), which
> appear to be just small SMPSs, there is some uncertainty, as they have a
> power range of 20 to 60 VA.
> So what happens when they drive only 5W? I tried it and it still works. No
> flickering, no dead LEDs.
> But what are the general implications of having not enough load on an
> "electronic transformer"?
> Can it cause damage to the LEDs lights or the SMPS electronics?
> How about the losses, bad efficiency with only 5W drawn?
> Has anyone schematics I could look at?
> Who's done it before? What's your experience?
> What other (affordable) options are there?
PSUs.
Instead of 12V DC.
.... Phil
Trevor Wilson
Mar 6, 2014, 2:22:08 AM3/6/14
to
with no issues (yet). The LEDs were cheapies from Aldi (20 Bucks for 4 X
4.5 Watt lamps). On the packaging, it clearly states that the LEDs are
not dimmable. Naturally, I tried them on my dimmer. They work fine,
albeit with a little flickering. With 9 downlights in the kitchen, the
power savings are not insignificant. The previous owner must have been
insane. 450 Watts of light is far too much for the room.
--
Trevor Wilson www.rageaudio.com.au
Tony
Mar 6, 2014, 6:41:36 PM3/6/14
to
MR16 halogen and 1 GU10 a few years ago. 13 of the MR16 have a Nelson
electronic "transformer", the other 7 are iron core. All the LED bulbs
are the cheap non-dimmable type for around $7 each on eBay or Kogan.
The failure rate on the conventional transformers is about the same as
the ones on electronic TRs.
According some statements of LED light sellers using the electronic
halogen light transformers on LEDs is considered "dodgy".
So I measured the waveform of the Nelsons. It is a "double-half" 100Hz
sinus 40Vpp chopped at 50KHz when loaded with a 20W halogen.
Similar but much smaller amplitude when open circuit.
Loaded with a 5W LED bulb (which is basically a bridge shottky
rectifier, 1 x some 200uF electrolyte and some constant current
switcher IC, like MT7201 and 3 or 4 LEDs) the wave form becomes a rather
messy with some ringing and hard to trigger.
Nevertheless, none of the components in the transformer gets even warm
to the touch and I noticed no radio interference, AM or FM.
So, in practice it is safe to say all is running fine.
Strictly speaking, however, I could/should
replace all 13 el.TRs with LED TRs at about $8 each or
replace all 13 LED bulbs with 50KHz suitable ones ($$$) which will
probably still not work any cleaner with the Nelson TRs or
replace all 13 down-light fittings and LEDs with GU10 types, of which I
haven't even found (yet) any fitting in the existing 80mm holes.
Before I waste any more time on investigating, I was curious to hear
what you guys are doing, cause I am sure most of you have replaced at
least some halogen lights with LEDs.
BTW, I have replaced my range hood lights (2x40W) with one of the super
bright LED strips you recommended some years ago (thanks!), 10W @ 11.5V
DC) from Dealextreme, which is even brighter with my DIY reflector:)
Tony
Dave Goldfinch
Mar 7, 2014, 3:42:09 AM3/7/14
to
On Wed, 5 Mar 2014 18:16:02 +1100, "Phil Allison" <phi...@tpg.com.au>
wrote:
Hi Phil
Am I right in thinking that the reason for this is that the rectifier
diodes in the LED lights are not likely to be fast recovery type and
therefore at risk of over heating resulting in early failure?
If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?
Dave Goldfinch
wrote:
Am I right in thinking that the reason for this is that the rectifier
diodes in the LED lights are not likely to be fast recovery type and
therefore at risk of over heating resulting in early failure?
If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?
Dave Goldfinch
Phil Allison
Mar 7, 2014, 4:51:57 AM3/7/14
to
"Dave Goldfinch"
>
> Hi Phil
>
> Am I right in thinking that the reason for this is that the rectifier
> diodes in the LED lights are not likely to be fast recovery type and
> therefore at risk of over heating resulting in early failure?
** That is just one of the concerns.
> Hi Phil
>
> Am I right in thinking that the reason for this is that the rectifier
> diodes in the LED lights are not likely to be fast recovery type and
> therefore at risk of over heating resulting in early failure?
> If you wanted to use the electronic transformer, would it be better to
> rectify the output using FR diodes (might not be economic)?
IME they can survive a brief short circuit and a overload of maybe 30%.
HOWEVER:
Operating with a rectifier and filter cap load is nothing like the same.
Operating with a rectifier and LED load is also not the same.
If you wanna be a total *smartarse* like the OP, what happens in non
predictable and your stupid fault.
BTW:
Why is it nearly EVERY fucking poster wants to do something that is stupid,
dangerous, impossible or illegal ??
Or all four at once.
No answer needed.
... Phil
done...@gmail.com
Sep 4, 2015, 12:16:57 AM9/4/15
to
Deez Nuts
Sep 4, 2015, 1:05:27 AM9/4/15
to
Phil's negatives outweigh the positives.
It's a shame because he is quite knowledgeable.
BuckyBalls
Sep 4, 2015, 6:18:32 AM9/4/15
to
university (too stupid to pass the exams) and no woman would go near him
so he just lives these days with Missus Palm and her five flexible
daughters to entertain himself with.
BuckyBalls
Sep 4, 2015, 11:16:37 AM9/4/15
to
On 4/09/2015 6:16 AM, done...@gmail.com wrote:
He had a shot at University, but he fucked up.
He once had a brain, but it has gone to trash over the abusive years.
Computer Nerd Kev
Sep 4, 2015, 6:26:45 PM9/4/15
to
got one.
Why we all had to be reminded of a thread from last year just for the
purpose of this rhetorical I don't know.
--
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