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Surge suppressor for wired PWS.

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--- Quote from: Wx4U on April 22, 2010, 02:15:47 PM ---I wasn't worried, Dan. I know you are always tinkering and when you have the surge surpressor done please share it with us.

--- End quote ---

O.K. Bob (and anyone else that may be interested). Success today in locating the needed components to wrap this project up.

It's just your off-the-shelf telephone line junction box with two jacks. It makes it easy having 2 rows with screws for the connections and the 2 jacks are now in and out (or line side and equipment side). The TVS diodes and MOV (varistors) are packed inside on the bottom. The fuses are up on the top to make it easier to change them if/when needed, just loosen the associated 2 screws and swap the fuse(s) out. The earth ground screw comes out the back of the enclosure. It may be a better design to add a series resistor on each line between the MOV and TVS diode but I left these out because I don't want to add line loss to the already lengthy cable run. Total resistance between in and out for each individual line is an acceptable .2 ohms due to the fuse. I plugged it into my ws-2310 stn. and it's chugging right along and still happy.

The components are rated to kick in (clamp) around 6vdc which is the lowest I could locate. At least it's a lot closer to the dc voltage it's protecting than a telephone surge protector was. I have a 6 foot copper ground rod outside about 10 feet away that it's connected to. Total cost (excluding the existing grounding rod) was around $7(US).
This could also be placed outside where a wired anemometer and/or rain gauge enters the thermo/hygro ISS but you would need to remember to run a ground from there.

Added Note: This design is only intended to dissipate, or drain off, power surges/spikes in the equipment wiring. A direct hit from lightning will go its own course and circuitry such as this will have no effect suppressing it.

 :-) Nice job, Dan.  Always fun and way less costly to build them yourself.

Thanks Henry. Part of the fun is trying to convey to the Thai shop owner what it is you want. I went prepared today with the schematic drawing I made (above). On the back I sketched a house with an anemometer on top with a wire connecting it to a computer inside. I drew a bolt of lightning above. Next to the computer, on the wire, was a box with the ground symbol. In my (extremely) broken Thai I was trying to explain what I was doing and needed to him when he looked at me and said, "yes we have varistors here, what size do you want?" His English was so good. Shocked me. I've been dealing with this guy for years and never knew we could speak to each other. :roll: Anyway he had everything I needed right there. It is fun, like you say.

Good component design. I think I might be able to put it together from your instructions.
Ha! I have had the same experience several times overseas...struggling to communicate, then they speak perfect English. Oh well, I guess they sometimes feel sorry for us.
Thanks for the work on the surge protector. It is an item those of us using cable components should have.

Thanks Bob. I took my UPS telephone suppressor out first to see if it could be modified before building this. It would have been nice to just swap out components for the needed values.  It turned out to be easier to just build a new one. If/when you decide to put one together, don't hesitate to ask if you have questions. That's what we're all here for. :grin:



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