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Problematic transformer

Shellyb1

Expert Member
Joined
Jun 23, 2011
Messages
1,365
#1
Recently had my wiring in the house redone. Bought the house a few years ago and I can swear they paid off an electrician for the COC.

In the rewire, the electrician put down the transformer in the picture. It's an Osram ET-Parrot 70/220-240 I/G transformer for all my down lights.

I had cheap LED bulbs from China mall that worked perfectly before these transformers were introduced. The previous transformers were old and mostly wired incorrectly and the need for these new ones came in.

LED light bulbs I use on these transformers are proving a pain in the behind and expensive. The China mall ones dont work or flash on or off. The new Osram/Polaroid/Eurolux LED bulbs do not work either.

I cannot seem to find a LED light bulb that works with it. I have tried halogen and they seem to work but I run on a solar PV system with batteries and the less draw the better so the halogens at 50w a pop is not good compared to the 3-4.5w the LED gives me.

Anyone have similar experiences with transformers? The electrician said I should use Opple bulbs but I cannot find them anywhere to even test them.
 

chrisc

Executive Member
Joined
Aug 14, 2008
Messages
6,803
#2
You need a different transformer. The one you are using needs a substantial load to make it work. Any reputable electrical supplier will have a transformer that will operate LED lights, with their small load

In Cape Town it would be Plumstead Electric
 

Shellyb1

Expert Member
Joined
Jun 23, 2011
Messages
1,365
#3
You need a different transformer. The one you are using needs a substantial load to make it work. Any reputable electrical supplier will have a transformer that will operate LED lights, with their small load

In Cape Town it would be Plumstead Electric
Thank you

Is it over kill for a home down light setup? Is that also why the 50w halogen works?Not sure why the electrician used these then.
 

chrisc

Executive Member
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Aug 14, 2008
Messages
6,803
#5
GU10 leds connect straight to the mains

MR16 leds use a 12 volt transformer

Leds use less than 1/10th of the electricity of an incandescent bulb, so the cost is worth it
 

savage

Expert Member
Joined
Aug 11, 2003
Messages
2,922
#7
I started with MR16, but after less than a year I dumped all my MR16's and transformers, and went to GU10.

Much, much better IMHO. When going LED, 3W is 3W. Whether it's 220V or 12V the consumption's the same.
 

agentrfr

Expert Member
Joined
Jul 8, 2008
Messages
4,570
#9
For goodness sake man, why 12V lights? You're not living in an RV. Chuck the lights and power supply out and replace everything with 220V GU10 lights - they're cheaper and you don't have to worry about 100 amps of electricity going through cables in the roof to start a fire.

The 220V GU10s will even work with modified sine / square AC from a cheap PV inverter.
 

me_

Senior Member
Joined
Oct 11, 2013
Messages
618
#10
If you look on the transformer, it will have a minimum wattage - those ones are 20-70W - the minimum draw has to be 20W for them to work.
That means at 3-4W per LED, you need a minimum of 6 globes connected to it for it to work (although you would probably want more otherwise all lights will die when 1 globe pops).
The older steel core transformers don't usually have a minimum wattage on then so they are better for LEDs, but the transformers aren't 100% efficient and are less efficient at low wattage. Also, the transformers can cause issues with LED dimmers.

I would agree with the general sentiment that the 220V GU10s are better than using transformers and MR16s. I've replaced all of mine - was a really quick job to do.
 

chrisc

Executive Member
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Aug 14, 2008
Messages
6,803
#11
Some people (who had halogen downlighters) will want to retain their 12 volt wiring and use MR16 LED lamps. I agree that GU10 makes it much simpler and are getting cheaper and cheaper, but there is no arguing with a customer who has made up his mind

However, I installed MR16 led lamps in an art gallery where they were suspended from cables between the walls and needed to have a decorative effect. For safety and compliance, it had to be a 12 volt system
 

Gnome

Executive Member
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Sep 19, 2005
Messages
5,572
#12
Try actually put a larger picture up so we can see what kind of transformer that is

Are you using a single transformer for multiple lights or a single transformer per light? (the latter is better from a reliability and heat perspective)
What is the line voltage at the terminals leading to the lamps?
Are these lamps rated for AC or DC?
Is that "transformer" a step-down transformer or AC->DC converter (same question for what was there before)? (Eg. have you inadvertently gone from an AC->DC system or vice versa)

The only time you install 12v lamps is due to safety requirements (eg. zones designated as an electrocution risk), that is the sole reason for the existence of these lamps.
Using them otherwise is simply due to ignorance (oh how many times I've seen people use them incorrectly)

IMO you shouldn't be installing this for other people unless you are a qualified electrician...
(And by qualified I mean you really understand what the caveats of this system is, what all the markings on a transformer are, etc.)
 
Last edited:

msquared

Expert Member
Joined
Mar 29, 2016
Messages
3,195
#14
MR16s (12V) have been banned in Germany. They are considered a fire hazard and rightfully so. My view is to remove all the transformers, get GU10 harnesses and just use GU10s direct. You won't have an issue.
 

Gnome

Executive Member
Joined
Sep 19, 2005
Messages
5,572
#15
MR16s (12V) have been banned in Germany. They are considered a fire hazard and rightfully so. My view is to remove all the transformers, get GU10 harnesses and just use GU10s direct. You won't have an issue.
Agree except that I would make sure the wires currently in there are 3 wire SANS rated wire.
Often the yahoos installing these simply use cheap PnP wire for the 12v systems

Also 12v lamps make sense where a lot of water is used. eg. swimming pool area, jacuzzi, etc.
The problem is local idiots installing it in normal rooms which it isn't specified for at all.
 

SauRoNZA

Honorary Master
Joined
Jul 6, 2010
Messages
27,962
#16
Why oh why would someone stick to 12v on a re-wire of they needed to replace them anyway.

Should have just gone 220v en Klaar.

Probably in an effort to skirt regulation or work as they are less full of *** about 12v.
 

msquared

Expert Member
Joined
Mar 29, 2016
Messages
3,195
#17
Agree except that I would make sure the wires currently in there are 3 wire SANS rated wire.
Often the yahoos installing these simply use cheap PnP wire for the 12v systems

Also 12v lamps make sense where a lot of water is used. eg. swimming pool area, jacuzzi, etc.
The problem is local idiots installing it in normal rooms which it isn't specified for at all.
100%

1. Use a qualified electrician
2. 12V is always used for safety... in the garden, by the pool, in the bathroom and for all shop fittings.
 

aquadat0r

Well-Known Member
Joined
May 6, 2010
Messages
343
#18
Some people (who had halogen downlighters) will want to retain their 12 volt wiring and use MR16 LED lamps. I agree that GU10 makes it much simpler and are getting cheaper and cheaper, but there is no arguing with a customer who has made up his mind

However, I installed MR16 led lamps in an art gallery where they were suspended from cables between the walls and needed to have a decorative effect. For safety and compliance, it had to be a 12 volt system
What is involved when conveting from 12V to 220V, except for the fittings themselves, does all the wiring need to be redone?
 
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