Using electronic transformers with LED MR16 down-lights

T

Tony

Guest
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
 
"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.
Click to expand...

** Who said you could use them with LEDs ??


But what are the general implications of having not enough load on an
"electronic transformer"?
Click to expand...

** Not the issue.


> Can it cause damage to the LEDs lights or the SMPS electronics?

** Not the issue.


> How about the losses, bad efficiency with only 5W drawn?

** Not the issue.


> Has anyone schematics I could look at?

** Google has.


Who's done it before? What's your experience?
What other (affordable) options are there?
Click to expand...

** Only LED lights specified as suitable for high frequency (ie 50kHz)
PSUs.

Instead of 12V DC.



..... Phil
 
On 5/03/2014 5:23 PM, Tony wrote:
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
Click to expand...

**I've been using mine (Crompton branded) with LEDs for several months,
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
 
On 6/03/2014 3:22 PM, Trevor Wilson wrote:
On 5/03/2014 5:23 PM, Tony wrote:
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

**I've been using mine (Crompton branded) with LEDs for several months,
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.
Click to expand...

You are right, the power savings are significant. I replaced 20 (twenty)
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
 
On Wed, 5 Mar 2014 18:16:02 +1100, "Phil Allison" <phil_a@tpg.com.au>
wrote:

"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 ??


But what are the general implications of having not enough load on an
"electronic transformer"?

** Not the issue.


Can it cause damage to the LEDs lights or the SMPS electronics?

** Not the issue.


How about the losses, bad efficiency with only 5W drawn?

** Not the issue.


Has anyone schematics I could look at?

** Google has.


Who's done it before? What's your experience?
What other (affordable) options are there?


** Only LED lights specified as suitable for high frequency (ie 50kHz)
PSUs.

Instead of 12V DC.



.... Phil
Click to expand...

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
 
"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?
Click to expand...

** That is just one of the concerns.


If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?
Click to expand...

** ETs are designed to drive resistive, halogen lamp loads.

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
 
On Friday, March 7, 2014 at 8:51:57 PM UTC+11, Phil Allison wrote:
"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.


If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?


** ETs are designed to drive resistive, halogen lamp loads.

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
Click to expand...

And why are you such a fucking negative ass hole?
 
On 04-Sep-15 12:16 PM, done.arun@gmail.com wrote:
On Friday, March 7, 2014 at 8:51:57 PM UTC+11, Phil Allison wrote:
"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.


If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?


** ETs are designed to drive resistive, halogen lamp loads.

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

And why are you such a fucking negative ass hole?
Click to expand...

Just stick him in your kill file list.

Phil's negatives outweigh the positives.
It's a shame because he is quite knowledgeable.
 
On 4/09/2015 6:16 AM, done.arun@gmail.com wrote:
On Friday, March 7, 2014 at 8:51:57 PM UTC+11, Phil Allison wrote:
"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.


If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?


** ETs are designed to drive resistive, halogen lamp loads.

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

And why are you such a fucking negative ass hole?
Click to expand...
Because Phil the Dill is a basically just a piece of shit, he failed at
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.
 
On 4/09/2015 6:16 AM, done.arun@gmail.com wrote:
On Friday, March 7, 2014 at 8:51:57 PM UTC+11, Phil Allison wrote:
"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.


If you wanted to use the electronic transformer, would it be better to
rectify the output using FR diodes (might not be economic)?


** ETs are designed to drive resistive, halogen lamp loads.

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

And why are you such a fucking negative ass hole?
Click to expand...
Because he failed at every thing he ever tried to do.
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.
 
Deez Nuts <g@a.com> wrote:
On 04-Sep-15 12:16 PM, done.arun@gmail.com wrote:
On Friday, March 7, 2014 at 8:51:57 PM UTC+11, Phil Allison wrote:

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

And why are you such a fucking negative ass hole?


Just stick him in your kill file list.
Click to expand...

"done.arun@gmail.com" is on Google groups, so I don't think they've
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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