Probably the ones I've had the most luck with are the Islatrol series from Control Concepts. I think they have been bought out by Emerson or Liebert or one of the other companies that have power divisions. Anyway, they call these "active tracking filters". They not only are TVSS's but also filter noise, low-amplitude spikes, etc. Right now I'm typing from a mountaintop site (broadcast) that we re-built a few years ago. We put in an Islator I-2100 (120/240V single-phase). The old equipment shelter which had been here since 1990 had the same model unit. In the 15+ years we've been managing and maintaining the site, we've had zero surge-related failures, and this site sticks out like a sore thumb as far as lightning goes. In the last few years I've used the same series of arrestors for new site builds at a dozen sites or so and have had no power-related problems.
Others that make comparable-quality products include Joslyn, Transtector, and Innovative Technologies. There is one big difference (to me anyway) between TVSS's, that being whether they are the series or parallel type. Series type takes the utility service (or transfer switch output if there's a generator too) as its input, and provides a protected output to feed the panel(s). Parallel type is typically connected to a breaker in the panel, which puts it in parallel with all of the loads. I much prefer series. Parallel type can be less effective because a) there will always be some inductance and resistance in the wiring between the panel and the protector, b) if the TVSS conducts, there's a good chance it will trip the breaker in the panel, resulting in no protection until the breaker is reset, and c) they are much less effective as a noise filter. The upside to parallel type is they can easily be added at any time just by popping breakers in the panel and feeding the arrestor. Series, on the other hand, are in-line with the service conductors, so if you want to add one (or repair one), you have to take the service down. Series tends to also be more expensive, especially for three-phase and unlike parallel type, the price goes up as the current rating goes up for obvious reasons. A good 200A single-phase arrestor of the ilk I'm talking about starts at about $1000 and goes up quite a ways from there. I think these single-phase I-2100's were in the $2000 range. I recently spec'ed a 120/208 3-phase Transtector (parallel type) for another site where I'm much less concerned about power-wise, and that was about $1800. No cheap, but where you're protecting equipment in the 6 and 7 figure range, it's a no-brainer. If you're repeater is a Micor mobile and an Astron, it might be hard to justify... :-) --- Jeff > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:repeater-buil...@yahoogroups.com] On Behalf Of Chuck Kelsey > Sent: Tuesday, June 08, 2010 11:34 AM > To: Repeater-Builder@yahoogroups.com > Subject: Re: [Repeater-Builder] MOVs for power supply primary > > > > Jeff - > > Could you suggest some makes and models and maybe explain why > they are > superior to others? > > Chuck > WB2EDV > > ----- Original Message ----- > > > Good surge arrestors/TVSS's are expensive, and like most > things in life, > > you > > get what you pay for. If your site has a good surge arrestor at the > > service > > entrance, you really shouldn't need anything extra. > > > > --- Jeff WN3A > > > > >