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Please let me know if there is anything wrong with this logic. So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage ...
Answer
#3: Post edited
by
Lorenzo Donati
·
2023-07-11T17:09:10Z (10 months ago)
Replaced link to dubious website (required enabling javascript and cookies), with direct link to PDF document from the original publisher of the poster.
- > _Please let me know if there is anything wrong with this logic._
- So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage and, providing you do not generate more then these zeners, it's virtually a rubber stamp job. It's likely you are going to be involved with North American standard but, they are similar. If you want to make comparisons I once found this wall-chart quite comforting when I was designing IS stuff (many projects over many years): -
- 
It can be downloaded from [here](https://manualzz.com/doc/14075912/mtl-flammable-facts-poster).- For the zener barrier I'm fairly certain that you will need a fuse here: -
- 
- > _In particular, is the logic of the maximum output current from the flyback transformer convincing for IS purposes?_
- No, use an extra fuse is my advice as per the modified diagram.
- > _Please let me know if there is anything wrong with this logic._
- So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage and, providing you do not generate more then these zeners, it's virtually a rubber stamp job. It's likely you are going to be involved with North American standard but, they are similar. If you want to make comparisons I once found this wall-chart quite comforting when I was designing IS stuff (many projects over many years): -
- 
- It can be downloaded from [here](https://www.mtl-inst.com/images/uploads/datasheets/posters/Eaton_MTL_FlamFacts_Poster_2015.pdf).
- For the zener barrier I'm fairly certain that you will need a fuse here: -
- 
- > _In particular, is the logic of the maximum output current from the flyback transformer convincing for IS purposes?_
- No, use an extra fuse is my advice as per the modified diagram.
#2: Post edited
by
Andy aka
·
2021-12-10T12:07:44Z (over 2 years ago)
- > _Please let me know if there is anything wrong with this logic._
So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage and, providing you do not generate more then this part is virtually a rubber stamp job. It's likely you are going to be involved with North American standard but, they are similar. If you want to make comparisons I once found this wall-chart quite comforting: -- 
- It can be downloaded from [here](https://manualzz.com/doc/14075912/mtl-flammable-facts-poster).
- For the zener barrier I'm fairly certain that you will need a fuse here: -
- 
- > _In particular, is the logic of the maximum output current from the flyback transformer convincing for IS purposes?_
- No, use an extra fuse is my advice as per the modified diagram.
- > _Please let me know if there is anything wrong with this logic._
- So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage and, providing you do not generate more then these zeners, it's virtually a rubber stamp job. It's likely you are going to be involved with North American standard but, they are similar. If you want to make comparisons I once found this wall-chart quite comforting when I was designing IS stuff (many projects over many years): -
- 
- It can be downloaded from [here](https://manualzz.com/doc/14075912/mtl-flammable-facts-poster).
- For the zener barrier I'm fairly certain that you will need a fuse here: -
- 
- > _In particular, is the logic of the maximum output current from the flyback transformer convincing for IS purposes?_
- No, use an extra fuse is my advice as per the modified diagram.
#1: Initial revision
by
Andy aka
·
2021-12-10T12:06:12Z (over 2 years ago)
> _Please let me know if there is anything wrong with this logic._ So far so good. The voltage clamp (3 zener diodes for European IS category iA and two for category iB) is the limiter on voltage and, providing you do not generate more then this part is virtually a rubber stamp job. It's likely you are going to be involved with North American standard but, they are similar. If you want to make comparisons I once found this wall-chart quite comforting: -  It can be downloaded from [here](https://manualzz.com/doc/14075912/mtl-flammable-facts-poster). For the zener barrier I'm fairly certain that you will need a fuse here: -  > _In particular, is the logic of the maximum output current from the flyback transformer convincing for IS purposes?_ No, use an extra fuse is my advice as per the modified diagram.