Specifications

d‐1

888‐2628‐300 WARNING:Disconnectprimarypowerpriortoservicing.

Maxiva ULX Series

November 11, 2013

Appendix-d

Lightning Protection Recommendation

d.1 Introduction

Whatcanbedonewitha2millionvoltpulsepushing220,000ampsofcurrentintoyourtransmittingplant?Likethe

500poundgorillaitdoeswhateveritwantsto.Thereisnotmuchthatcanbedonetoprotectagainstamajordirect

lightningstrike.Thisiscalleda

significantimpulselightningstroke.Itusuallylastslessthan 100microsecondsandis

mostdestructivetoelectronicequipmentbecauseitcontainshugeamountsofhighfrequencyenergy.

Herearesomeexamplesofthisdamage:

• Melted ball and horn gaps.

• Ground straps burned loose.

• H.V. rectifier stacks shorted.

• Massive arc marks in the output circuit of AM transmitters.

• Ball lightning traveling into building on outer conductor of transmission line.

Figured‐1isamapoftheUnitedStatesthatshowsthenumberoflightningdaysexpectedinanyyear,with

Colorado,NewMexico,andFloridaleadingthelist.

Figured‐2showstheincidentstotallstructures.Atrig geredeventisonethathappensbecausethetowerwas

present.Withoutthetowerthestrikewouldnothaveoccurred.

Figure d-1 Map Showing Lightning Days Per Year