Back in the 70's I worked as an Engr for a broadcast AM/FM station. One day after a bad storm the night before, there was a message that during the storm, the evening DJ had seen some flashes in the control room from one of the equipment racks.
Each of our 19 inch racks had power coming in at the bottom to conduit running up the rack with 4x outlet boxes at several points up the back side of the rack to the top. The chief Engr had us wire up MOV's to 110V AC plugs and stick an MOV into one of the outlets at each box leaving the other three for equipment to plug into. Looking at the rack, all of the equipment in the rack was working fine except a pilot light of one unit. Opening up the back, the outlet box at the bottom had two prongs sticking out where the MOV had been the rest of the AC plug and MOV were gone. The next box up the MOV was black instead of red but intact and the AC plug was fine. The MOV at the top of the rack looked completely normal. The only other damage in the control room was a black arc mark between the bail of an HP freq counter and the rack it was sitting on top of. Seeing what had happened to those MOV's and seeing that all the equipment in the rack still worked fine made me a believer in using MOV's. John Lock kf0m at arrl.net > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] Behalf Of Eric Lemmon > Sent: Thursday, September 27, 2007 10:21 PM > To: Repeater-Builder@yahoogroups.com > Subject: RE: [Repeater-Builder] AC Line Conditioner > > > Don, > > Thanks to some advertising hype being spread by manufacturers of > so-called "surge suppressors", one might think that some kind of > a surge suppressor is a "must-have" accessory. Not! A > properly-designed electrical distribution system does not need > such pathetically inadequate gimmicks. As a power engineer for > Boeing, I see many instances of our IT people being pressured to > install surge suppressors where they are completely unnecessary. > > It is the responsibility of the utility to provide an AC power > source that is appropriately protected with fuses and surge > arrestors at the distribution level- usually 12kV or 22kV. Once > inside the radio shack, each station should have a > properly-grounded 120 VAC feed, along with appropriate protection > of the antenna feedline. The highest priority should be to > ensure that every conductor that enters each radio equipment > cabinet has the *SAME* ground reference for protection. > > If you are converting the incoming AC to nominal 14 VDC floating > on a battery, you should be okay. > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: Repeater-Builder@yahoogroups.com > [mailto:[EMAIL PROTECTED] On Behalf Of Don KA9QJG > Sent: Wednesday, September 26, 2007 11:55 PM > To: Repeater-Builder@yahoogroups.com > Subject: [Repeater-Builder] AC Line Conditioner > > > I Would like some input on What some are using for a AC Line > Conditioner not a UPS , For a Repeater site that may not have > the Cleanest AC Coming in . I do have a 50 Amp Astron with the > Battery Backup on a Battery. I know that should Clean most things > up, But I am a little concerned about what’s coming in. on the > AC, I also have Great grounding and a Poly Phaser on the Antenna Side. > > > > Thanks Don > > KA9QJG > > > > > > > > Yahoo! Groups Links > > > >
