DETA transformer anomaly

[ThePredator]

I have tested a DETA LED lighting electronic transformer.  This is the one that bunnings sell.  What is labelled as a constant voltage transformer is NOT a constant voltage transformer. In fact its no better than the Halogen lighting transformer voltage output.  Comparing this to the Phillips ET-S 15W shows that the phillips version is a constant voltage and spot on. 

The Phillips works with any number of LED MR16 lights up to the maximum wattage and holds its output voltage very well.  The DETA  version appears to be false advertising

[MitchellMc]

Welcome to the Bunnings Workshop community @ThePredator. It's great to have you join us and many thanks for your feedback.

I will pass this information the information provided on to our Merchandise team to look into further. We appreciate you bringing this to our attention. 

We would be more than happy to return the item with a refund or exchange.  Please let me know if you needed any help facilitating this.

Many thanks once again.

Mitchell

[ThePredator]

I've checked this a bit more and I think the higher than expected AC voltage may be due to the switching frequency of the electronic transformer. I'm in the process of selling and moving and all my bench test equipment is packed away so I'm only using a cheap Klein and Jaycar pair of multimeters to progress most of my rewiring. The main factor in all this is what's in the LED lamp being used. I assume for the price I paid for it, that it would be a  bridge rectifier followed by a smoothing capacitor and if the DC peak voltage at this point is too high, the capacitor and other components in the lamp will fail in a shorter time frame. There are other factors but this was one of my main concerns,

[Walzz]

@ThePredator  I assume this is the unit you are complaining about.
https://www.bunnings.com.au/deta-12v-15w-dimmable-electronic-transformer-for-led-globes_p0097824 
The output of the Deta transformer is chopped DC and will produce erronous readings on most digital multimeters.
These units are built to a price and I would expect the Phillips ET-S 15W to be much better engineered in comparison (and a little more expensive).
Not sure about MR16 LED bulbs, but I strongly suspect they have no smoothing capacitor, just an internal bridge rectifier to ensure compatibility between electronic transformers that produce quasi DC, and legacy iron transformers with 12v AC output.

My personal opinion is that the Deta transformer will probably be OK but if budget will allow, use the Phillips ET-S 15W instead.

[ThePredator]

Agree, 

In this day and age and all the buzzwords being used about life expectancy, in this case consumer lighting, nothing has changed. LEDs are still sub-par for the cheaper ones. C-tick means stuff-all if you buy chinese brand items. Cheap solar panels produce huge amounts of RFI. I'm still waiting for sustainable electricity supplies from the government. And the battery mess that's coming in the next 20 years. 

[MikeTNZ]

Hi @ThePredator,

Could you please explain how this power supply was tested?

Was this under load and what sort of test equipment did you use to perform these tests?

I think what @Walzz  was referring to, was that if you don't use a True-RMS meter (or even better an oscilloscope) the results you derive are going to be rather inaccurate.

To say that solar panels themselves create a lot of RFI, is missing the point, it is the charge controller that causes RFI, but the wiring to the panels act as antennas and don't help the situation, especially if the installer did the cheapest job they could and I see a lot of these sorts of jobs as an electrician after the neighbours baby-monitor now has a terrible squeal coming out of it.

Don't get me wrong, I'm not having a go at you, I've worked with electricity for over 35 years and a lot of this new technology (in parts) is really messing up the RF spectrum.

Cheers,

Mike T.

[ThePredator]

Yes, under load with MR16 led downlights (In parallel of course). I did'nt use a CRO initially, mine were all packed ready to move to a new dwelling. But I took the whole kit and kaboodle in to work finally and did a bench test. We have an electronic load tester at work. 

Where the Phillips converter gave a consistent O/P voltage, the Det-A failed miserably.  The Phillips obviously has a very good voltage regulator on the output. Maybe a simple modular regulator, maybe a more complex one.  I don't know, its sitting in the ceiling of the previous house obviously doing a magnificent job because the new owner has not messaged me any complaints about the new ceiling lights.

There are a lot of remedies that can be carried out to mitigate RFI from switchmode PSUs. Unfortunately, and this is what happens regularly, there is no government regulation in Australia that places the onus on the installer to test for RFI. Electricians do not have the technical skills to investigate RFI. Unless the installation is being done for a large contract where the customer expressly requires an RFI check and mitigation done and requires high quality PSUs with minimum RF noise, the domestic customer gets what they paid for. I always see very high noise floor levels and interference in city surrounds. Simply, you can check where its coming from using a small yagi and a cheap spectrum analyser or an SDR.