An isolation transformer without any protection probably wouldn't offer much as the higher frequency components of the transient would probably pass the transformer through capacitive coupling between the windings. I'm sure the Transtector has some type of protection/ clamping. That price range ($1k) is where the stuff that actually works starts.
The "series" style AC protectors are best as they have some inductance the incoming power has to flow through and the higher frequency components of the transient create a high enough voltage to trigger the protectors before the transient is seen by the equipment. The parallel style protectors subject your equipment to the same voltage required to trigger the protection. As per the Polyphaser white paper and other sources it is possible to pick a strike size you want to survive and engineer for that successfully (grounding system, single point entry for all I/O's and protectors on all I/O's, etc.) which becomes even more complicated when you have IDU/ODU systems since you're trying to keep all I/O's and grounds more or less at the same potential during the strike and give it somewhere to go (ground). Greg On Aug 6, 2009, at 10:39 AM, David Hulsebus wrote: > I looked at a Transtector unit a few weeks ago. It's an isolation > transformer that sits outdoors between the entrance panel and our > internal electrical system. It was roughly $1K for the unit. Kind of > wish I would have bought it now. We are the end of the line on the > power > grid and have 1-3 days of outages multiple times a year, that's the > real > reason for the battery solution; that and we are tired of generators. > > Your right though. Most cell and radio towers I visit have just > that, an > isolation transformer at the entrance panel. > > Thanks, Dave > > [email protected] wrote: >> Since it sounds like this came in on the AC, how about a surge >> protector >> on incoming AC line? We've had sites where the power company's >> grounding >> is so bad we've lost power supply surge protectors in just about >> every >> storm that comes through the area...until we put surge protection >> at the >> breaker box. Now all is good. >> >> Cameron >> >> >>> Don't feel too left Chuck out we lost a tower site in the same >>> storm. >>> Second time in seven years a total loss. Both times we've lost our >>> gear >>> it has come via the electrical side. Our tower gets hit by a >>> strike or >>> two almost every storm and we never have issues. This time it >>> literaly >>> blew the entrance panel off the side of the building and outlets >>> off the >>> walls of the building. Cracked one of the APC batterty units, every >>> ethernet surge suppressor and every grounded POE injectors were >>> blown >>> apart. Interesting that our four coax arrestors were okay, but the >>> gear >>> was cooked. Most of the cat5 ends included. Had spare gear on the >>> tower plugged in at the radios but dangling in the building, we >>> fired it >>> up and were in operation within a few minutes. Took another 16 >>> hours to >>> get all of the damage cleaned up. >>> >>> We have on that site forty-five 3/4" ground rods in two concentric >>> circles around the tower and building none more than eight feet >>> apart; >>> all interconnected with #2 bare stranded wire and cad welded. >>> Inside the >>> building - a halo ring and 3 1/2" copper strapping, the list goes >>> on and >>> on for what we have done to minimize issues. We spent nearly 5K on >>> grounding and still lost it all. >>> >>> We are moving to total battery power next week. I am looking for >>> something I can use to isolate a smart charger from the power >>> company >>> when we see storms in the area, I expect we will have enough >>> battery for >>> a minimum 3 days runtime. Some type of relay that we can control >>> remotely I would guess. >>> >>> If it makes you feel any better Verizon Wireless took total loses on >>> four towers between Cincinnati and Louisville Tuesday as well. >>> >>> Dave Hulsebus >>> Portative Technologies, LLC >>> >>> Chuck Hogg wrote: >>> >>>> Has anyone been able to withstand a direct lightning strike? We >>>> had a >>>> tower get hit last night, and some of our equipment lost Ethernet >>>> ports >>>> (RB/433AH), and we lost 3 canopy APs, but that is all >>>> (considering what >>>> is all up there only 2/3rds was blown). Our Trango AP survived >>>> and a >>>> RB/433AH survived. Even Nextel had their guys out there, but >>>> they just >>>> had to reset alarms it appears as nothing was "fried" on their >>>> end. I >>>> wish I had to just reset alarms. >>>> >>>> >>>> >>>> So tell me, what do you do ? I'm tired of dumping a few grand >>>> during big >>>> lightning storms. >>>> >>>> >>>> >>>> I do the basics, Ethernet surge suppression up top and on the >>>> bottom, >>>> Polyphasers, ground out to the ground bars, ground out the cat5 >>>> cable, >>>> and no omni's. >>>> >>>> >>>> >>>> Regards, >>>> >>>> Chuck Hogg >>>> >>>> Shelby Broadband >>>> 502-722-9292 >>>> [email protected] >>>> >>>> http://www.shelbybb.com >>>> >>>> >>>> >>>> >>>> >>>> -------------------------------------------------------------------------------- >>>> WISPA Wants You! Join today! >>>> http://signup.wispa.org/ >>>> -------------------------------------------------------------------------------- >>>> >>>> WISPA Wireless List: [email protected] >>>> >>>> Subscribe/Unsubscribe: >>>> http://lists.wispa.org/mailman/listinfo/wireless >>>> >>>> Archives: http://lists.wispa.org/pipermail/wireless/ >>>> >>>> >>> -------------------------------------------------------------------------------- >>> WISPA Wants You! 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