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Thread: Why are the alarms clocks and Microwave running fast?

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    Default Why are the alarms clocks and Microwave clock running fast?

    Hi all,
    Just a quickie I hope
    Have a Tortech inverter (well, had - have the same problem) 5kw 24v to 240AC PSW.

    It powers 2 digital alarm clock radios and the microwave (as well as other household items), but I've noticed the clocks are running fast. Might be 1 minute every two/three days.

    As you all might remember I had moisture get into the 'old' 5kw one and it ran the clocks quick.

    As the 5kw died a week ago, I now have a brand new 6kw version (same model, colour, switches, exactly the same - but 6kw), and it's running the clocks quick!
    So this running quick is obviously linked. The supplier doesn't know why!?

    Just wondering if (whatever), the effect is, could it harm the fridges or other electrical devices?
    I don't run expensive things off the inverter (lounge big tv, main computers and screens etc).


    The display on the inverter is showing 50hz and 245VAC. There is a setting to make it 60hz, but it is set to 50hz.

    If I measure the hz at a wall GPO it's reading 50.124hz of which the last 3digits fluctuate a bit here and there.
    Last edited by GT250; 07-04-19 at 08:10 AM.



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    hi , you are on the right track with frequency 50/60hz the problem arises as the inverter frequency changes with input and temp and is always correcting its self to maintain a average of 50/60 hz
    cheers don

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    How fast?

    The frequency you measure could cause the clocks to creep but if they are gaining minutes a day then I'd suggest the wave form is not right and that is causing the increased clock speed.

    As for not running expensive electronics off something, I'm always amused by that parroted FUD that is so prevalent.
    I HAVE run a lot of " delicate" and " expensive" electronics off very shitty power supplies and never had a problem.

    If you look inside these things, the more exy the appliance, the generally better power supply and filtering they have. Most will these days run 100-250V and 50-60 Hz and beyond. Doesn't much matter, the majority of equipment will run a transformer , drop the power down to 12 or 5V, run that through a bunch of voltage controllers and caps to smooth it all out and then supply the board. The input and output are usually isolated now so spikes are dampened as well. A computer power supply puts out very stable power from any rubbish input and has a lot of circuitry to ensure that.

    I have run video gear off crappy sq wave inverters along with computers, printers, Monitors, chargers and load of other stuff for days at a time adding up to months over all and never had a problem. I also used to run stuff off those cheap arse 2 stroke generators that had a frequency particularly all over the shop and never had a problem with that either.

    Motors and resistance loads are more like power smoothing devices than anything else. Motors and square wave inverters aren't a great idea but a true sine wave inverter even if not great isn't going to worry a motor. Regular induction motor is more likely to stabilise the inverter and keep frequency variations in check.

    I'm sure some crappy gear has dodgy power supplies but if it's decent then the power supply witch usually rectifies the power to low volt DC or in some cases ramps it up to thousands of Volts, isn't anywhere near as sensitive as perpetuated Urban myth makes out.

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    Those appliances must be deriving their 'clock' signal from the mains frequency and the 50Hz from the inverter is just a whisker fast like 50.01Hz is enough to gain a minute every 3 days. Assuming you're running off the inverter alone (no grid connection) that is but I know someone who had clocks running fast with a grid connected solar inverter too which turned out to be noise on the output of the inverter throwing in an extra cycle now and then from memory.

    Most appliance clocks now seem to be based on their own crystal oscillators so should be completely independent from mains frequency, obviously not all though.

    Even the mains 50Hz is just a 'nominal' figure and the generators try to maintain +/- 0.1Hz around 50Hz and keep track of the error in terms of seconds fast or slow compared to an ideal steady perfect 50Hz. The error is compensated for to achieve average zero time error by running the system a little faster or slower as required but staying within the acceptable frequency range at all times.
    Last edited by Skepticist; 07-04-19 at 10:08 AM.

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    AFAIK most inverters would get their 50Hz divided from a crystal clock which would be at least 2 orders of magnitude more accurate than what you are reading, although multimeter frequency measurements normally are just as inaccurate.
    There must be a controller board where you can see a multi-legged chip and the crystal, but maybe they are using a ceramic resonator which is a bad idea to save a few pennies but would explain that bad tolerance.
    Photo of the controller board might help get to the bottom of this.

    50.1 or even up to 51Hz won't damage your fridge, 60Hz is a different story.
    Last edited by Uncle Fester; 07-04-19 at 03:31 PM.
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    Hi,
    Many thanks for your replies people.

    George65, in my very younger years of all this solar/inverter stuff, I've had MSW inverters and had lines running up the tv screens... PSW solved that.
    There's a good reason why PSW is much expensive than PSW. Guess though that the price difference isn't that much nowadays...
    I'm not going to risk $$$ tv's and other high end products on a $1500 standalone 240v device. I'll let Energex, handle the hz and 240+-10VAC on those things

    I will add though that I have had three digital alarm clocks fail. I suspect a 'surge' from the old 5kw caused it. I opened them up (first two of them), and found that from the direct 240VAC (A and N), going into the transformer - and two (same colour), leads coming out to the pads that had AC on them, showed no VAC.

    The microwave had also reset the clock - flashing 00:00:00. I would find that through the followings days the MW clock would keep resetting without being used.

    I replaced the two clocks and put a third in. Maybe a day later, the MW was flashing again and the clock was dead! I opened it up and found again no output from the transformer.

    The Inverter has a toggle switch to 50hz. So I'm not going to play around with flicking it to 60hz to see what happens, guys
    I measured the hz with a cheapo 'power save, watt meter' gadget and then my Fluke 289. Both were just showing a touch over 50hz...

    Nomeat: When I had this issue, the bar fridge (which has a PS on board, had gone as well). $40 and new PS and all is well.
    The other fridges didn't miss a beat, thankfully.
    All this stuff as mentioned is/was on the 5kw inverter.

    However, I found out in this period my main Air Con in the house had failed as well! Obviously not connected the 5kw.
    Compressor motor had 'fused' according to the A/C experts. Had been using it frequently as due to the hot/humid weather recently up in SEQ. It was 14yrs old - maybe a coincidence...?

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    I think the problem with "dirty" power was an issue of last century when multilegged fuses were just that. Modern componentry is way more resilient than stuff of old. That does not negate the need for power conditioners, though. Spikes can, and do, still take out more electronics than just high or low voltage.
    I'm out of my mind, but feel free to leave a message...

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    Had a guy come out on Friday to look at the washing machine. @0 year old hoover/ Simpson finally bit the dust with a leaking gearbox seal. I'm going to pull it out , see if I can clean up the GB and get it going again as the rest of the thing seems great.

    Guy spotted the meter I had in the laundry power point. He said is that 251V that is reading. I said yep, typical round here. He said do you have solar? I said not on that phase, that's the mains Voltage all on it's own. We had discussed which was the best new machine to buy but he said you need a line conditioner because no modern electronic machine will like that. He nominated one which I now for get as had no interest in and said they are very sensitive to voltage and will die in no time on that.

    The Mrs isn't about to let me put my big online UPS and a couple of batteries in the laundry to run the machine off so when she bought the new one I told her to make sure she got the max extended warranty. Thing shits itself now in the next 6 years and I don't care. If it lasts that long it will be good till it dies of some other reason. Repair guy laughed when I said you think I'll get 20 years out of the next one I buy? He said spend $3 grand on a Kleenmaid and you most likley will, anything else think yourself very lucky to get 10 years.

    We got a Simpson which has the same gut's as my old one. Pulled the lint filter out and it is indeed the same. Confident with the mechanicals, remains to see how the electronic controls hold up.

    If I can get the old washer going again wouldn't surprise me if it does the same as My old fridge. Replaced that because it was making noises and was about 15 yo anyway. It got relegated out the back as a beer fridge and got rained on a couple of times a year when the water blew in under the awning.

    Replaced the replacement and the old one is still going strong. It's over 30 YO now. Only thing seems to be wrong is the thermostat has become sensitive and if it's not turned low it turns into a very effective freezer.

    Should just give it a coat of paint and bring the thing back in as the main fridge.

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    Quote Originally Posted by GT250 View Post
    Hi,


    I will add though that I have had three digital alarm clocks fail. I suspect a 'surge' from the old 5kw caused it. I opened them up (first two of them), and found that from the direct 240VAC (A and N), going into the transformer - and two (same colour), leads coming out to the pads that had AC on them, showed no VAC.

    The microwave had also reset the clock - flashing 00:00:00. I would find that through the followings days the MW clock would keep resetting without being used.

    I replaced the two clocks and put a third in. Maybe a day later, the MW was flashing again and the clock was dead! I opened it up and found again no output from the transformer.

    The Inverter has a toggle switch to 50hz. So I'm not going to play around with flicking it to 60hz to see what happens, guys
    I measured the hz with a cheapo 'power save, watt meter' gadget and then my Fluke 289. Both were just showing a touch over 50hz...

    Nomeat: When I had this issue, the bar fridge (which has a PS on board, had gone as well). $40 and new PS and all is well.
    The other fridges didn't miss a beat, thankfully.
    All this stuff as mentioned is/was on the 5kw inverter.

    However, I found out in this period my main Air Con in the house had failed as well! Obviously not connected the 5kw.
    Compressor motor had 'fused' according to the A/C experts. Had been using it frequently as due to the hot/humid weather recently up in SEQ. It was 14yrs old - maybe a coincidence...?
    Looks like you are a victim of Murphy's law here.
    I have not used a mains powered alarm clock in 30 years.
    Maybe time to move on and get battery operated LCD ones or go back in time and get some cool retro mechanical ones.
    I am a clock nutter and have from radio synched clocks that pick up a time code signal from Japan to a clock I made of stone and everything you might imagine in between EXCEPT a fully mains operated one.

    Q: Are you switching between grid and offgrid(like I do every night) and with what?
    Every time you are switching you could be doing something very nasty to the fridge compressor.
    Update: A deletion of features that work well and ain't broke but are deemed outdated in order to add things that are up to date and broken.
    Compatibility: A word soon to be deleted from our dictionaries as it is outdated.
    Humans: Entities that are not only outdated but broken... AI-self-learning-update-error...terminate...terminate...

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    Hi all,

    I'll just live with it. Was just a quickie question.

    nomeat: Just that I had the clocks and they run off the Solar Batts - so free to run. I don't switch change anything, the house has the normal wiring, and there's a separate from the inverter, wiring into the house.
    So basically there are dual GPO's in the walls.
    I try and run most 'continuous' drain stuff off the solar batts.

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