Transformers are tuned for a particular frequency and will resist passing other frequencies that's how transformers clean up dirty power.The 30W ultra-small series module power supply is a small, high-efficiency power supply module designed by Hi-link Electronics for customers. Read all about Fourier Analysis to understand that. * When a sinewave is less than perfect, that acts as harmonics. So on a 500 VA transformer with a 120V primary, that section is rated for 4.16 amps etc. You just need to make sure you are within the transformer's current limits for each section. Clever selection of primary:secondary ratios can get you all sorts of places. If you can't find that size remember you can use two transformers back-back, with primaries connected to each other. Further, the transformer removes any need for your switched output to even go negative! You could make a sinewave that is 0-12V peak-peak (so 4.24VAC RMS with a +6V bias).įeed that into a 4.24:12V transformer and you'll have a respectable true 12VAC coming out the other side. (at the expense of the suppressed harmonics* heating up the transformer, so you'll need to derate it so it can stay cool). Because having a transformer in the stage will tend to clean up the sine waves and block HV chatter. If you can run it through an isolation transformer, you don't even need to really be all that sine-wave-ish. It's not "all on you" to make the perfect sinewave you only need to get into the ballpark and let a transformer clean it up further. They might give you something out of left field, like "We make 'em in DC too, the only difference is a $21 module we can sell you." But your idea is a good one.Īnd closer than you think. I bet they can either give you a "How" or at least, a "why not". A phone call to the factory for advice should really be your first stop. Since these lights are expensive, they ought to be well-supported. Do the research to exhaustion, then act based on facts. I also violently disrecommend "trying" anything on either a) AC mains or b) prohibitively expensive components. Not surprising, 17 VDC is a very different customer than 12VAC RMS, with twice the overall power into a resistive load. Tried up to 17 V DC to take the sinewave peak into account. I've got some good comments below on solutions to power my lights - but still interested in hearing if anyone has used low-cost PSW driver boards. Can anyone share their experience of trying to do something similar? I’ve been looking at single board drivers like Sunyima’s EGS002 module using their EG8010 controller chip. I was wondering if there are simpler approaches, especially modular ones. I only need a 20 W output, but haven't found any low voltage low power inverters. While this started in response to a lighting challenge, it's now a more generic enquiry. A MSW/square wave output may damage components over time, and as I said, these lights are expensive. And I'd prefer the output to be pure sine wave - at a low (50 to 60 Hz) frequency, as I know the lights will work then. Intellectual curiosity took hold, and wondered if I could make a simple low voltage 12 V DC to 12 V AC 50/60 Hz PSW converter based on a modern PSW inverter control chip – plus I wouldn’t need such high-voltage components for the power stage and keeping everything LV makes it inherently safer.Īs everything is off-grid and solar/battery powered, I'm looking for high-efficiency solutions. I have an electronics background and designed stuff many years ago. And this may be the easiest and most cost-effective solution - but it's not ideal. I could convert 12 V DC to 120/230 V AC using a cheap commercial inverter then transform down again to 12 V AC (or possibly replace the inverter’s output transformer). There's no marking on the lights identifying them, and my local supplier isn't helping with this. These pool lights are too $$$ expensive – and sealed – for me to tear down. There's clearly some AC coupling involved. I tried up to 17 V DC just in case the lights relied on some peak threshhold detection, without success. For whatever reason my pool lights can't. Most normal “AC” LED lights have a bridge rectifier on the input, so can run from DC. While they work fine using 12 V AC, they don't work off the battery. This started with me trying to power 12 V AC LED swimming pool lights - which are always spec’d as AC for historical (and consequently safety certification) reasons - from a hefty 12 V DC leisure battery.
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