What would happen if your ac power system uses 240V and you are using a 230V-115V step down transformer?

Would it degrade the winding faster?

Why is there a 230V-115V ac? what countries use it?

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    This guy is a scammer tired of his continual Questioning of non legal systems and then using answers in the next question with no up vote for any one helping. – Ed Beal Nov 22 '18 at 2:55
  • Because when I first joined.. I couldn't up vote... beginners at stack exchange can't up vote.. it's only now that I'm aware I can up vote already... and I just upvoted the answers by Ed and others. And I don't know comments should be upvoted too. – Samzun Nov 22 '18 at 2:57
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    No you can always up vote a question you asked you consistently challange at least 3 professionals on this site , with nothing other than time wasting questions I and others have spent a lot of time trying to help so i finally decided to let others know. – Ed Beal Nov 22 '18 at 3:07
  • When I tried to upvote last week. I couldn't because new users need to have certain reputations first before they can upvote. try asking the system owner. I'm sorry. Can't you forgive me and give me one more chance? – Samzun Nov 22 '18 at 3:08
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    I asked you to do this several times as many folks have tried to answer your questions , Harper, 3phase ,and several others you come up with new questions based on answers that should have been accepted , plus many comments of folks that may not be pros but have provided good advice , after many many attempts to help you I decided it was time to make a point, we want to help you, but only challenging with out knowledge and not giving credit for a good answer that will come up again is a bit upsetting, give credit when there is an answer or comment and we can help. – Ed Beal Nov 22 '18 at 3:26

You're talking about that step-down transformer you bought.

Step-down transformers are designed to turn a 230V Euro-style supply into a 120V North American style output. They are designed to do this all day, all night, for as long as the device lasts.

The life of the device will be decided by its build quality. Is a General Electric product better than a brand-you've-never-heard-of East Asian made cheapie? Oh, you bet it is. Still, a transformer has no moving parts, so expecting long life is reasonable.

  • My question is this. My ac supply is 240V (when you measure any outlet with a voltmeter).. now when I'd use a 230v-115v transformer (not one I already bought but stil planning to buy (a Hammond brand)), won't the 230v be low for 240V that it can damage the winding after long term use? Should I get a 240v-120v transformer instead? – Samzun Oct 15 '18 at 22:29

I really don't understand your question. First a transformer (xfmr) which accepts a single phase 240V input does not really step down to a 230/130V output the voltages are nominal, meaning they are virtually the same. So now that we have that straight, the named output of 230/120V simply means that you have added a grounded center tap to the output coil and you now have a dual voltage output. 230V across the phase and 120V grounded neutral.

Technically speaking it would not degrade a winding it is simply the way it is made.

These type of xfmr's are used anywhere you would need to split a voltage and add a neutral.

Hope this helps

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    There are single phase models not split taps, this is quite common with equipment coming from the UK or going over there so equipment mfg's can use the devices from there area. Once the voltage is transformed one side of the secondary is grounded in this case and becomes a separately derived source. – Ed Beal Oct 15 '18 at 21:44

220? 230? 240? It's all the same to me, bro

Around the world, the closest thing to a standard mains voltage that exists is referred to interchangeably as 220V, 230V, 234V, or 240V -- it is extremely rare these days to run into a device that cares enough about mains to care about the difference between 220V and 240V on the input, and most mains supplies have a broad enough voltage tolerance (+/- several %) anyway that a device that did care that much would need special care and feeding anyway.

So, go ahead and plug your transformer into 220, 230, or 240V -- while the output voltage will vary slightly between the different input voltages, it should still be within specification for whatever you plug into the output.

  • What if a switching power adapter for CCTV or cellphone or gadget has voltage range of 100-240v and the power c inputted is 90 volts.. what would happen to the adaptor? how low below the lowest can it still run? Or does the IC inside it is strict that it can only turn on if at least 100 volts? – Samzun Oct 16 '18 at 3:28
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    @Samzun -- there will be a undervoltage lockout on the supply's IC that will keep it from turning on at too low of a mains voltage -- but there's no need to plug such a universal input power supply into a transformer to begin with, as it will be happy on any mains voltage from 100 to 240V. – ThreePhaseEel Oct 16 '18 at 3:54
  • I'm using a 127v MCOV SPD type 3. And to have safety margin. I can't use 120 volts output of my 220volts ac power (I can't use 220volts SPD because clamping voltage will be very high). So I need to use 100 volts output from transformer or voltage regulator. But if the power sags to 95v or 90v.. would the switching power supply still work? Can it's ic take 95 volt power for instant when it says 100-240v range? – Samzun Oct 16 '18 at 4:46
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    @Samzun -- why don't you just get a 220-240V SPD then? :/ – ThreePhaseEel Oct 16 '18 at 11:34
  • the let-thru voltage of 220-240 SPD are very high.. in the 1200 volts.. whereas for 120 volts.. it's only let thru of 330v to 500v – Samzun Oct 16 '18 at 12:06

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