When using a mains transformer in reverse to step up a voltage it is important that the stepped-up output does not significantly exceed the original rated primary voltage of 230V (or 115V) otherwise the iron in the transformer core will become magnetically saturated. This will cause excessive current drain and high losses in the transformer. If you want to get higher output voltages you really need to rewind the step-up transformer to add more turns. For example, if you want to use a reverse connected 230V rated transformer to obtain 300V output you need to increase the number of turns on the output winding by around 30%.
Thanks or the detailed info. I was experimenting to see if I could use them that way as they will only be seeing very small loads. I was hoping that they would handle it OK, and to a point they could but if I used too small a transformer, or (as you said) too large an output voltage then it would warm up. My final design does not actually use this reversed transformer method, but I thought the experiment would be interesting to people anyway, as it was all part of the project development. It could still be done this way with the correct transformer choices using a slight over voltage on the output, but care is needed to avoid pushing it too much.
A transformer can magnetically saturate even with no load on it. The transformer's ability to handle a voltage without saturating depends on on the number of turns, the frequency, the area of the iron core and the type of steel in the core. For an existing core the only ways to safely increase the operating voltage are to either increase the number of turns or increase the operating frequency - not a practical option when operating off of a mains supply.
Check Mr. Carlson's lab : ruclips.net/video/LhovRIM5xAo/видео.html His Tester was designed to replace the now expensive Heathkit high voltage Tester with low voltage
Yes I had already started this project before he published his to his Patreon supporters. My version is different to what he has made as I am using a LCD display and an Arduino, I intend to make my design public, not just to my Patreon supporters (I could really use more Patreon's... anyone spare a $?)
why can i hear when you hook up a lead to the transformer? its not a bad noise its like when you unhook an audio input im just curious i do like your video bud!
Thumbs up for the video, but it seems like you only need a small amount of current for this application (to deal with the inrush) so you could have done this with a battery source and a DC to DC boost converter followed by a doubler. The main advantages would be safety, portability, lower volume, and significantly lower cost for those who don't have transformers lying around... Regardless, should be an interesting project!
www.pa4tim.nl/?p=1385 at the bottom of the page. I use two the same transformers and a switch to chose 265V or 500Vdc max. With a shunt mosfet I can regulate from 0V to 500V. Nothing exotic.
When using a mains transformer in reverse to step up a voltage it is important that the stepped-up output does not significantly exceed the original rated primary voltage of 230V (or 115V) otherwise the iron in the transformer core will become magnetically saturated. This will cause excessive current drain and high losses in the transformer.
If you want to get higher output voltages you really need to rewind the step-up transformer to add more turns. For example, if you want to use a reverse connected 230V rated transformer to obtain 300V output you need to increase the number of turns on the output winding by around 30%.
Thanks or the detailed info. I was experimenting to see if I could use them that way as they will only be seeing very small loads. I was hoping that they would handle it OK, and to a point they could but if I used too small a transformer, or (as you said) too large an output voltage then it would warm up. My final design does not actually use this reversed transformer method, but I thought the experiment would be interesting to people anyway, as it was all part of the project development. It could still be done this way with the correct transformer choices using a slight over voltage on the output, but care is needed to avoid pushing it too much.
A transformer can magnetically saturate even with no load on it. The transformer's ability to handle a voltage without saturating depends on on the number of turns, the frequency, the area of the iron core and the type of steel in the core. For an existing core the only ways to safely increase the operating voltage are to either increase the number of turns or increase the operating frequency - not a practical option when operating off of a mains supply.
Nice project for the workbench and really accessible for the regular tech on a reduced budget.
I intend to make the design public once I have finished it, both the Gerbers and the Arduino code.
Check Mr. Carlson's lab : ruclips.net/video/LhovRIM5xAo/видео.html His Tester was designed to replace the now expensive Heathkit high voltage Tester with low voltage
Have you watched Mr carlson Lab ...Invention Release! Carlson LV Capacitor Leakage Tester.
Video here, schematic available to his Patreon followers:
ruclips.net/video/LhovRIM5xAo/видео.html
to his Patreon followers!
Yes I had already started this project before he published his to his Patreon supporters. My version is different to what he has made as I am using a LCD display and an Arduino, I intend to make my design public, not just to my Patreon supporters (I could really use more Patreon's... anyone spare a $?)
why can i hear when you hook up a lead to the transformer? its not a bad noise its like when you unhook an audio input im just curious i do like your video bud!
Thumbs up for the video, but it seems like you only need a small amount of current for this application (to deal with the inrush) so you could have done this with a battery source and a DC to DC boost converter followed by a doubler. The main advantages would be safety, portability, lower volume, and significantly lower cost for those who don't have transformers lying around... Regardless, should be an interesting project!
ats89117 - thanks I will bare it in mind, this is very much an experiment to see if I can make something useful.
www.pa4tim.nl/?p=1385 at the bottom of the page. I use two the same transformers and a switch to chose 265V or 500Vdc max. With a shunt mosfet I can regulate from 0V to 500V. Nothing exotic.
Please change the intro music . it's not fit in modern world .
It was modern when he was young.
I made that music....
It's hideous!
I like it