OK, I should have been more specific. What would be a reasonable unit for a repeater site that may have only a couple thousand dollars worth of equipment inside?
Chuck WB2EDV ----- Original Message ----- From: "Jeff DePolo" <j...@broadsci.com> To: <Repeater-Builder@yahoogroups.com> Sent: Tuesday, June 08, 2010 4:22 PM Subject: RE: [Repeater-Builder] MOVs for power supply primary > > 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
