Transformer Isolated Surge Suppression System
Recent circuit breaker blogs by MIDWEST have dealt with circuit breakers and surge suppressors. For expensive computer equipment, superb surge suppression is vital. Surge suppression is exceedingly cheap insurance for such applications. The initial / replacement equipment costs can be expensive. But even more importantly, downtime and data loss can be catastrophic.
In fact, when putting together my own home computer system, I considered surge suppression so extremely important, that I put together my own 3 stage surge suppression system.
The 3 stage system consists of:
- a 3000 Joule commercial surge suppressor strip, with integral circuit breaker.
- a custom designed and built, transformers isolated power conditioner.
- a 2000 Joule commercial surge suppressor strip.
The 3000 and 2000 Joule commercial surge suppressor strips were the highest quality (i.e. expensive) that I could find. But surge protection is so important, that I considered these insufficient.
Therefore, I additionally designed and built a custom transformer isolated power conditioner. It contains a 2 KVA dry transformer and six metal oxide varistors. It also contains four RC snubber networks for high frequency EMI attenuation. The main purpose of the transformer is to provide additional series impedance. The design of the power conditioner is covered in a separate blog.
The theory behind the entire scheme is that each stage of the surge suppression system helps dissipate the spike’s energy. An applied voltage spike first is partially dissipated by the building’s line impedance and the first 3000 Joule suppressor strip. The portion of the spike that gets through is next attenuated by the custom transformer isolated power conditioner. In addition, this helps slow down steep wavefronts and reduce EMI. The final 2000 Joule surge suppressor strip attenuates whatever spike remains.
A block diagram of the system is shown in the Visio diagram below.
3 Stage Surge Suppression System