| Electronics > Beginners |
| Using a 120V Variac on 230V |
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| perieanuo:
--- Quote from: Hero999 on December 06, 2018, 05:04:14 pm --- --- Quote from: Swake on December 06, 2018, 04:33:06 pm ---Found an original 120V Variac in very good condition. It is a 60ties or 70ties model. Is there anything that would refrain me from using it on 230V? The amperage rating should be halved to maintain same power rating of course, but anything else? --- End quote --- * Yes it's frequency dependant. You could theoretically use it at 230V, if the frequency were increased to 120Hz. Of course there's a limit to how far this can be pushed as hysteresis losses in the core increase with frequency and the insulation can only take a certain voltage before failing. * Measuring the current would do. --- End quote --- can't stop laughing omg old variac=old transformer with voltage taken from intermediary transormator position.FREQUENCY DOESN'T CHANGE.come back after learning electronics basics. https://en.wikipedia.org/wiki/Autotransformer https://www.ebay.fr/itm/Autotransformateur-VARIAC-500VA-tension-variable-0-250-VAC-3-Amp-230V-NEUF-/272778656159 pierre |
| Zero999:
--- Quote from: perieanuo on December 07, 2018, 08:30:45 am --- --- Quote from: Hero999 on December 06, 2018, 05:04:14 pm --- --- Quote from: Swake on December 06, 2018, 04:33:06 pm ---Found an original 120V Variac in very good condition. It is a 60ties or 70ties model. Is there anything that would refrain me from using it on 230V? The amperage rating should be halved to maintain same power rating of course, but anything else? --- End quote --- * Yes it's frequency dependant. You could theoretically use it at 230V, if the frequency were increased to 120Hz. Of course there's a limit to how far this can be pushed as hysteresis losses in the core increase with frequency and the insulation can only take a certain voltage before failing. * Measuring the current would do. --- End quote --- can't stop laughing omg old variac=old transformer with voltage taken from intermediary transormator position.FREQUENCY DOESN'T CHANGE.come back after learning electronics basics. https://en.wikipedia.org/wiki/Autotransformer https://www.ebay.fr/itm/Autotransformateur-VARIAC-500VA-tension-variable-0-250-VAC-3-Amp-230V-NEUF-/272778656159 pierre --- End quote --- What are you on about? Of course transformers don't change the frequency. I never said they did. I was talking about how the voltage can be doubled, without cooking the transformer. Go back and re-read my post! |
| perieanuo:
--- Quote from: Hero999 on December 07, 2018, 08:53:42 am --- --- Quote from: perieanuo on December 07, 2018, 08:30:45 am --- --- Quote from: Hero999 on December 06, 2018, 05:04:14 pm --- --- Quote from: Swake on December 06, 2018, 04:33:06 pm ---Found an original 120V Variac in very good condition. It is a 60ties or 70ties model. Is there anything that would refrain me from using it on 230V? The amperage rating should be halved to maintain same power rating of course, but anything else? --- End quote --- * Yes it's frequency dependant. You could theoretically use it at 230V, if the frequency were increased to 120Hz. Of course there's a limit to how far this can be pushed as hysteresis losses in the core increase with frequency and the insulation can only take a certain voltage before failing. * Measuring the current would do. --- End quote --- can't stop laughing omg old variac=old transformer with voltage taken from intermediary transormator position.FREQUENCY DOESN'T CHANGE.come back after learning electronics basics. https://en.wikipedia.org/wiki/Autotransformer https://www.ebay.fr/itm/Autotransformateur-VARIAC-500VA-tension-variable-0-250-VAC-3-Amp-230V-NEUF-/272778656159 pierre --- End quote --- What are you on about? Of course transformers don't change the frequency. I never said they did. I was talking about how the voltage can be doubled, without cooking the transformer. Go back and re-read my post! --- End quote --- in fact you're right, I misread. but don't forget, wire gauge on transformer has current in equation, you can't just double the voltage amplitude AND the freq and put this as possible scenario, tha's just not engineering.putting aside core saturation, everyone knows every respected manufacturer put just the material to do the job with maybe 20% margin but not 100%. not speaking of isolation matters added by doubling voltage. Scenarios like this are just sci-fy.he can't do what he ask, point. you can make drawings all day long, I say no, bad idea. I noticed lot of people on this forum put on paper idea |
| perieanuo:
--- Quote from: Hero999 on December 07, 2018, 08:53:42 am --- --- Quote from: perieanuo on December 07, 2018, 08:30:45 am --- --- Quote from: Hero999 on December 06, 2018, 05:04:14 pm --- --- Quote from: Swake on December 06, 2018, 04:33:06 pm ---Found an original 120V Variac in very good condition. It is a 60ties or 70ties model. Is there anything that would refrain me from using it on 230V? The amperage rating should be halved to maintain same power rating of course, but anything else? --- End quote --- * Yes it's frequency dependant. You could theoretically use it at 230V, if the frequency were increased to 120Hz. Of course there's a limit to how far this can be pushed as hysteresis losses in the core increase with frequency and the insulation can only take a certain voltage before failing. * Measuring the current would do. --- End quote --- can't stop laughing omg old variac=old transformer with voltage taken from intermediary transormator position.FREQUENCY DOESN'T CHANGE.come back after learning electronics basics. https://en.wikipedia.org/wiki/Autotransformer https://www.ebay.fr/itm/Autotransformateur-VARIAC-500VA-tension-variable-0-250-VAC-3-Amp-230V-NEUF-/272778656159 pierre --- End quote --- What are you on about? Of course transformers don't change the frequency. I never said they did. I was talking about how the voltage can be doubled, without cooking the transformer. Go back and re-read my post! --- End quote --- in fact you're right, I misread. but don't forget, wire gauge on transformer has current in equation, you can't just double the voltage amplitude AND the freq and put this as possible scenario, tha's just not engineering.putting aside core saturation, everyone knows every respected manufacturer put just the material to do the job with maybe 20% margin but not 100%. not speaking of isolation matters added by doubling voltage. Scenarios like this are just sci-fy.he can't do what he ask, point. you can make drawings all day long, I say no, bad idea. I noticed lot of people on this forum put on paper idealistic things.Reality is sadly different. I never want to argue for nothing, but you cannot advice a beginner to try such thing, the guy can loose an eye for example, burn his thumb or whatever cause somebody gives 'maybe will work like this' ideas. pierre |
| Zero999:
--- Quote from: perieanuo on December 07, 2018, 09:05:23 am --- --- Quote from: Hero999 on December 07, 2018, 08:53:42 am --- --- Quote from: perieanuo on December 07, 2018, 08:30:45 am --- --- Quote from: Hero999 on December 06, 2018, 05:04:14 pm --- --- Quote from: Swake on December 06, 2018, 04:33:06 pm ---Found an original 120V Variac in very good condition. It is a 60ties or 70ties model. Is there anything that would refrain me from using it on 230V? The amperage rating should be halved to maintain same power rating of course, but anything else? --- End quote --- * Yes it's frequency dependant. You could theoretically use it at 230V, if the frequency were increased to 120Hz. Of course there's a limit to how far this can be pushed as hysteresis losses in the core increase with frequency and the insulation can only take a certain voltage before failing. * Measuring the current would do. --- End quote --- can't stop laughing omg old variac=old transformer with voltage taken from intermediary transormator position.FREQUENCY DOESN'T CHANGE.come back after learning electronics basics. https://en.wikipedia.org/wiki/Autotransformer https://www.ebay.fr/itm/Autotransformateur-VARIAC-500VA-tension-variable-0-250-VAC-3-Amp-230V-NEUF-/272778656159 pierre --- End quote --- What are you on about? Of course transformers don't change the frequency. I never said they did. I was talking about how the voltage can be doubled, without cooking the transformer. Go back and re-read my post! --- End quote --- in fact you're right, I misread. but don't forget, wire gauge on transformer has current in equation, you can't just double the voltage amplitude AND the freq and put this as possible scenario, tha's just not engineering.putting aside core saturation, everyone knows every respected manufacturer put just the material to do the job with maybe 20% margin but not 100%. not speaking of isolation matters added by doubling voltage. Scenarios like this are just sci-fy.he can't do what he ask, point. you can make drawings all day long, I say no, bad idea. I noticed lot of people on this forum put on paper idealistic things.Reality is sadly different. I never want to argue for nothing, but you cannot advice a beginner to try such thing, the guy can loose an eye for example, burn his thumb or whatever cause somebody gives 'maybe will work like this' ideas. pierre --- End quote --- The magnetising current wouldn't change and the extra heating could easily be avoided by not running it at its full current rating. In practise, I wasn't seriously suggesting the original poster should actually use double the voltage at double the frequency. It just isn't practical as they're highly unlikely to have a 230VAC 120Hz power supply available. They could theoretically use a variable frequency drive, but that has other issues, such as high frequency harmonics and voltage spikes, so would be a bad idea. |
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