The case for 230VAC in Australia - Page 1
Forum section: electronics / general

author: fzabkar
author_rank: Super Contributor
timestamp: October 20, 2024, 01:19:01 am
content: Yes, I know 230VAC is the standard, but 240VAC is still the typical mains voltage that we see.Could Australia’s outdated voltage standards be taking years off the life of your toaster?https://www.theguardian.com/australia-news/2024/oct/19/could-australias-outdated-voltage-standards-be-taking-years-off-the-life-of-your-toasterQuote

author: Halcyon
author_rank: Unknown
timestamp: October 20, 2024, 04:22:52 am
content: I would have thought electronics are designed to tolerate significantly higher voltages than nominal line voltage, whether it be 230 or 240V.From a computing aspect, the minimum I can set the upper threshold for the input voltage, before my UPS kicks in is 264VAC (the maximum is 276V).

author: fzabkar
author_rank: Super Contributor
timestamp: October 20, 2024, 04:42:55 am
content: Quote from: Halcyon on October 20, 2024, 04:22:52 amSure, but the reliability at higher voltages is measurably lower. At least that was the finding of a current university study.That said, my immediate thought was whether US appliances lasted any longer than Australian or European ones.

author: Halcyon
author_rank: Unknown
timestamp: October 20, 2024, 04:45:52 am
content: I think it's a tough call and comes down to the build quality of the appliance at the end of the day. Would I expect a $15 toaster to last longer than a year or two? Probably not. Would I expect a $3000 computer to last many years, if not decades? Absolutely. I've had server gear running, some for 15+ years almost non-stop. I've replaced 1 power supply in that time.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 20, 2024, 05:03:00 am
content: Quote from: fzabkar on October 20, 2024, 04:42:55 amLink to the study? We need to critique the assumptions and test methodology.

author: Bud
author_rank: Super Contributor
timestamp: October 20, 2024, 05:33:53 am
content: Duplicate threadhttps://www.eevblog.com/forum/news/dave-seen-this-grid-overvoltage-story-in-the-guardian

author: Whales
author_rank: Super Contributor
timestamp: October 20, 2024, 06:02:02 am
content: Lots of confusing stuff in this Guardian article. Would love to see if it's based on an actual article that I can read or just unpublished stuff like interviews (I think it's the latter).QuoteI'm not sure about this and want to read further into where they got it. It's not clear who they're citing (Christopher from the last paragraph?).Some induction motor loads lose efficiency at lower voltages, others increase. I'm not sure what the average is across a network.Eg see Table 2 pg 6 (pg 306).Anything with a control loop (air conditioner, fridge) will probably see a drop in efficiency and increase in average power draw. These are the sort of appliances they might not be able to fit in their temp chamber unless it's really big.QuoteVery interesting. Universal brushed motors under high load and running quite hot. Would you get the same lifetime increase by turning down their speed slightly with the control most vacuum cleaners have? Or would that make no difference?QuoteIt would be worth them clarifying if this means we're not currently meeting the 230v standard or not.QuoteI have not diagnosed many failed SMPS so I wonder about this. Does average voltage stress on the main bus and switchers kill them? Or do they fail from dry electrolytics more often, in which case you want whatever input voltage maximises their efficiency?(Or maybe they're talking about transient high voltages rather than more averaged cases?)Don't quote me on this, but I suspect different SMPS will have their efficiency go either up or down when mains input voltage decreases. It probably has to do with their main transformer windings ratio and their main chopper duty cycle (is 50% best?). Anyone know for certain?

author: EEVblog
author_rank: Unknown
timestamp: October 20, 2024, 06:27:31 am
content: Quote from: Andy Chee on October 20, 2024, 05:03:00 amYep, I would immediately question it as well.Any well designed product should not see an impact on its life based on line voltage.

author: mariush
author_rank: Super Contributor
timestamp: October 20, 2024, 06:38:14 am
content: Switching power supplies in computers rectify the AC voltage to DC to get around 325v and then active power factor correction boosts this voltage to around 400-420v DC.Power supplies of lower wattage (like let's say 30-50 watts) may not have active PFC but still, it shouldn't matter.I imagine toasters and other such devices that have resistive elements may break down faster if they use elements designed for 200-210v AC

author: fzabkar
author_rank: Super Contributor
timestamp: October 20, 2024, 06:52:52 am
content: Quote from: Bud on October 20, 2024, 05:33:53 amSorry. Can we just kill this thread?BTW, the study is a work in progress by Dinidu Jeewandara Mudiyanselage at the University of Wollongong.https://www.uow.edu.au/apqrc/our-people/Project: Assessment of the Impact of Supply Voltage Magnitude on Consumer Appliance Lifespan

author: themadhippy
author_rank: Super Contributor
timestamp: October 20, 2024, 10:10:37 am
content: don't Australia not only have a declared voltage,but also a permitted tolerance? In the uk were 230V -6%, +10% so it can sit anywhere between 216v to 253V and stuff is supposed to be designed to operate between those limits

author: brucehoult
author_rank: Super Contributor
timestamp: October 20, 2024, 02:57:46 pm
content: Quote from: themadhippy on October 20, 2024, 10:10:37 amThere are also faults.I woke up one day last year and found that half the outlets and lights etc in the house were running at 140 V and the other half at 340 V. It turned out that there was a bad connection in the 11kV transformer at the road and neutral was at 100V relative to ground, while the two phases were at the correct voltages -- my supply is 480V AC with a center tap for neutral.Amazingly, almost everything coped. The coffee machine and water pump got 140 V which wasn't enough for the motors to run. The oven also. It worked, but took 40 minutes instead of 15 minutes to heat to pizza temperature. One cheap chinese wall-wart let out magic smoke on 340V, and the dehumidifier made a pop and stopped working (replaced under warranty ... I kept mum about the supply problem). The LED lighting in the ceiling didn't seem to care either way, and neither did any of my computers or monitors.

author: amyk
author_rank: Super Contributor
timestamp: October 20, 2024, 11:27:17 pm
content: It's well known that incandescent bulbs have a lifespan inversely proportional tothe sixteenth powerof the voltage. Heating elements in toasters work at the lower end of incandescence so they may follow a similar characteristic.On the flip side, SMPS tend to be more efficient at higher inputs due to lower resistive losses.

author: langwadt
author_rank: Super Contributor
timestamp: October 20, 2024, 11:52:34 pm
content: Quote from: themadhippy on October 20, 2024, 10:10:37 amdidn't UK switch to 230 +/-10% like the rest of EU in 2008 or something like that ?

author: coppice
author_rank: Super Contributor
timestamp: October 21, 2024, 12:04:07 am
content: Quote from: langwadt on October 20, 2024, 11:52:34 pmIn theory, yes. At the wall socket its still rare to see anything lower than 240V. 250V seems more common, from my experience. My power is at 247V at this moment.

author: brucehoult
author_rank: Super Contributor
timestamp: October 21, 2024, 12:48:26 am
content: Quote from: amyk on October 20, 2024, 11:27:17 pmIf the heat (or light) output follows the same proportion then with higher voltage your toast will cook faster, so you can probably cook the same number of slices of toast in the toaster lifespan.Not that I've even in my life seen a toaster burn out the element.

author: coppice
author_rank: Super Contributor
timestamp: October 21, 2024, 01:05:00 am
content: Quote from: amyk on October 20, 2024, 11:27:17 pmToaster elements are so much cooler than an incandescent lamp filament that there is no comparison. A toaster generally has a bare resistive wire for the heater. It is so cool it doesn't even need to be protected from rapid oxidation, let alone evaporation. An incandescent lamp filament dies through evaporation of the tungsten filament. That's why the glass is grey at the end of their life. It is coated in tungsten. The reason tungsten halogen lamps last much longer is there is a nice chemical cycle that occurs when tungsten is in a halogen gas. They have a quartz bulb (rather than soda glass, for temperature tolerance) that is much smaller than the soda glass bulb of a conventional incandescent lamp. This keeps the glass in a temperature range where halogen will combine with any tungsten coating the bulb. As this tungsten halide passes the filament, the temperature is then in a range where the halide breaks up, and the tungsten is free to rejoin the filament. A tungsten halogen bulb doesn't fail through tungsten evaporation. It fails when the redepositing has become so uneven there is a thin spot where the filament breaks. You need to run a tungsten halogen bulb quite hard to keep it in the right temperature range for the cycle to work. You can optimise the bulb size for a higher temperature than a conventional bulb, and get a whiter light. You can optimise for a similar temperature than a conventional bulb, and get a longer life.

author: Geoff-AU
author_rank: Frequent Contributor
timestamp: October 21, 2024, 04:20:11 am
content: Quote from: coppice on October 21, 2024, 01:05:00 amWould be interesting to see a chart of bulb lifetime vs output power (compared to nominal). Sounds like there's a goldilocks zone for halogen bulbs, unlike regular bulbs which simply die faster the harder you run them.

author: EEVblog
author_rank: Unknown
timestamp: October 21, 2024, 05:22:59 am
content: Quote from: brucehoult on October 21, 2024, 12:48:26 amMe neither.And I live in the top end of the voltage 245V-253V environment.

author: tom66
author_rank: Super Contributor
timestamp: October 21, 2024, 09:39:56 am
content: Quote from: Whales on October 20, 2024, 06:02:02 amIt's definitely a factor. With a typical cheap flyback SMPS the primary transistor has voltage stress of around 2x rectified line voltage across this. This will increase the chance of failure as dV/dt will increase across this transistor with higher mains voltage. The failure of this transistor is quite common, albeit less so in modern devices.

author: themadhippy
author_rank: Super Contributor
timestamp: October 21, 2024, 12:32:45 pm
content: QuoteCant point to a chart,just experience. When the uk "switched" to 230v sevral suppliers started selling lamps from the european market,as there sales area was larger the lamps were cheaper.However it soon became very apparent the life was shorter,instead of changing a lamp once or twice a year we were changing them 3 or 4 times,very quickly wiping out the few quid saving per lamp.The other issue was the colour temperature was noticeable different in a rig with mixed voltage lamps,

author: nali
author_rank: Frequent Contributor
timestamp: October 21, 2024, 12:53:38 pm
content: Quote from: EEVblog on October 21, 2024, 05:22:59 amOur rural supply is mostly around 250-253V. The only real failures I've had are halogen bulbs used in the oven and cooker hood. The hood bulbs only lasted a few months, unfortunately LEDs not an option.Oh, there was that induction hob I posted about when I was doing a repair for someone, but that was a crap design.

author: Someone
author_rank: Super Contributor
timestamp: October 21, 2024, 08:55:25 pm
content: Quote from: Geoff-AU on October 21, 2024, 04:20:11 amNo goldilocks zone, almost the same as vacuum bulbs (if not worse). An easy reference "GE Short G9 Capsules":https://docs.rs-online.com/6b9f/0900766b812170d8.pdflife is proportional to the -9th power of voltage! While intensity does not drop off so badly, but they push up the curve so hard that separate 230V and 240V parts are produced. Regulated transformers for low voltage halogen not looking so silly now.

author: tooki
author_rank: Super Contributor
timestamp: October 21, 2024, 09:20:17 pm
content: Quote from: Someone on October 21, 2024, 08:55:25 pmAlso interesting that that document expressly states that the life curves are valid for AC only, and that DC and half-wave rectified AC will reduce lifespan due to “harmful unidirectional tungsten deposition within the coil.”

author: Halcyon
author_rank: Unknown
timestamp: October 21, 2024, 11:59:00 pm
content: Quote from: nali on October 21, 2024, 12:53:38 pmI was having the same issue (see:https://www.eevblog.com/forum/chat/replacing-oven-interior-lamps). I'd have to check when I get home, but I'm pretty sure I'm running 24v bulbs at the moment and they have lasted a lot longer than the original 12v bulbs. Although not sure that relates at all to the incoming mains voltage?

author: nali
author_rank: Frequent Contributor
timestamp: October 22, 2024, 08:31:03 am
content: Quote from: Halcyon on October 21, 2024, 11:59:00 pmIn mine they are 230V bulbs, and bulb lifetime is related to voltage. In the couple of years we've lived in this house both oven bulbs and both hood bulbs have been replaced. The hood bulbs are the small 25W G9 types and the replacements lasted maybe 6 months? (and yes, they are oven lamps not the general purpose variety).

author: tom66
author_rank: Super Contributor
timestamp: October 22, 2024, 11:37:38 am
content: I think I've had one or two LED bulbs die since I started using them around 10 years ago. None of the Ikea Zigbee bulbs I have bought have failed yet though I've only been running them for about 18 months. These do contain small radio modules and an always-on SMPS, so it will be interesting to see if they have issues in the longer term compared to conventional LED bulbs. It's pretty much become a non-issue for me... though I don't buy the absolute cheapest bulbs.

author: coppice
author_rank: Super Contributor
timestamp: October 22, 2024, 06:47:32 pm
content: Quote from: tooki on October 21, 2024, 09:20:17 pmThe temperature of the filament ripples a lot through the cycles of the mains. I wonder if that is a major factor in hitting the sweet spot for tungsten halide to break up and redeposit the tungsten successfully.

author: Zero999
author_rank: Super Contributor
timestamp: October 23, 2024, 09:45:30 pm
content: Quote from: nali on October 21, 2024, 12:53:38 pmYes LEDs are an option. It doesn't get that hot under the cooker hood. I use LED lamps in mine and they're fine. You do need good quality ones, designed for enclosures. The first Lidl ones I had failed, but I replaced them with better ones and have had no problems since.

author: coppice
author_rank: Super Contributor
timestamp: October 23, 2024, 11:04:43 pm
content: Quote from: Zero999 on October 23, 2024, 09:45:30 pmFrom the temperature point of view you are right, but does his hood use weird bulbs not available in LED form?

author: nali
author_rank: Frequent Contributor
timestamp: October 24, 2024, 09:31:14 am
content: Quote from: coppice on October 23, 2024, 11:04:43 pmNo, not weird, they're 230V G9 type bulbs. The bulbs themselves sit in a capsule with a label "NOT SUITABLE FOR LED" or something like that. So I guess they've experienced a high failure rate.It's a slimline design so there's not a whole bunch of room (most of the space is occupied by a filter), though I feel they could have designed the thermals a bit better.

author: Zero999
author_rank: Super Contributor
timestamp: October 24, 2024, 09:41:09 am
content: Quote from: nali on October 24, 2024, 09:31:14 amIt should be fine.One thing you can do with many modern LEDs is remove the cover and change the current sense resisor for a higher value, to reduce the current, which will reduce the brightness, but greatly prolong the life. If you buy LEDs with a much higher lumen rating than desired, then it compensates for the this.YouTuber Big Clive has made some videos which show how to do his.

author: tom66
author_rank: Super Contributor
timestamp: October 24, 2024, 10:38:34 am
content: That connector definitely looks like a low voltage one so I suspect the 'not suitable for LED' will come from the bulbs being driven by a 12V electronic transformer which many capsule 12V LED bulbs will not work with. Either the transformer will fail to start, resulting in flashing LEDs, or the LED will flicker continuously as the transformer does not switch well. The output from electronic transformers is usually something like 30~80kHz AC modulated at 100Hz (or 120Hz if you're in a 60Hz country), this tends to confuse many switch mode power supplies resulting in poor output stability.I had this issue with a cabinet that had an integrated transformer for halogen lights, unfortunately the genius furniture makers had buried the transformer behind the oak structure and therefore it was not something I could change. What I did notice however was the transformer only had a startup issue, once it had started all was fine. So I rigged together a simple circuit with a relay and a resistor. The resistor applied 10W load to the transformer on startup for around 1 second, then the relay switched out the circuit (I used a half wave rectifier, resistor and large-ish capacitor to delay the relay activation time). This was enough for the transformer to start and then when it was happy the LED lights would glow continuously. The LEDs consume 2W each, so 4W total, compared to the original halogen solution of 50W. There is a subtle buzzing from the transformer so it's perhaps not 100% happy but you can't hear it unless you put your ear to the cabinet, and it's been working fine for two years so far. The circuit is small enough to be hidden inside the cabinet above where the lights fit.

author: Zero999
author_rank: Super Contributor
timestamp: October 24, 2024, 11:59:12 am
content: Quote from: tom66 on October 24, 2024, 10:38:34 amThere are LED replacement halogen lamps which will work from a high frequency electronic transformer. I bought some for my parent's bathroom, nearly 10 years ago and they're still going strong.Another option is to replace the electronic transformer with a 12V PSU. I know that wasn't an option for you, but might be for nali.

author: tom66
author_rank: Super Contributor
timestamp: October 24, 2024, 12:15:30 pm
content: Quote from: Zero999 on October 24, 2024, 11:59:12 amI tried using LED replacement halogens in my case. They didn't satisfy the load requirement and the output pulsed on and off. Presumably they'd be ok with the HF modulation though, likely they are just using a resistor, full bridge rectifier and 3 white LEDs in series to get approximately 12V ac operation. Whether they work depends entirely upon whether the electronic transformer can support the low load operation.

author: vk6zgo
author_rank: Super Contributor
timestamp: October 24, 2024, 12:18:44 pm
content: Quote from: amyk on October 20, 2024, 11:27:17 pmBack in the day, when incandescent lamps were made in Australia, the nominal "240V" ones gave nearly identical reliability & life times in Western Australia which due to complex historical reasons, had 250v Mains, to that in any other State.The "new wave" of management in the lamp companies thought it would be a lovely idea to shut down the factories, import "240v" lamps from overseas & increase their profit margin. The imported lamps had reduced lifetime in the 240v States, but they were tolerable.Not so in WA, where the lifetime reduction was quite pronounced.The lamp companies came up with a fix, by importing "260v" lamps and selling them to the "consumer" at a higher price.Alas, they weren't any better than the 240v ones.There was much agitation, mainly at the instigation of a particular EE, so the State Energy Commission spent a "king's ransom" To drop the voltage to 240v.The imported lamps were still crap!

author: vk6zgo
author_rank: Super Contributor
timestamp: October 24, 2024, 12:31:54 pm
content: Quote from: brucehoult on October 21, 2024, 12:48:26 amOld ones made in the 1930s & '40s did burn out the elements when the Toaster was 20 to25 years old. Replace the element & it was good for another couple of decades, but people wanted "new-fangled pop-up" toasters!Even those had reasonable lives, but these days, you are lucky to get 5 years out of a toaster----not the elements but everything else.

author: Zero999
author_rank: Super Contributor
timestamp: October 24, 2024, 01:15:12 pm
content: Quote from: tom66 on October 24, 2024, 12:15:30 pmThat might work for some electronic transformers, but some tricks are required to ensure the LED driver works with most electronic transformers.Here's an application note and a data sheet of an IC designed for this.https://pdfserv.maximintegrated.com/en/an/AN5372.pdfhttps://www.ti.com/lit/ds/symlink/tps92560.pdfI'd expect higher quality LEDs, sold as electronic transformer compatible are more likely to live up to their claims.