eventlogbackup.ps1

#requires -version 3.0

#remote computers must be running PowerShell 3.0

$computers = "chi-dc01","chi-fp01","chi-dc04","chi-fp02"
$cred = Get-Credential globomantics\administrator
$eventlog = "Application"

invoke-command -ScriptBlock {
  $log = get-wmiobject win32_nteventlogfile -filter "logfilename = '$using:eventlog'"
  $file = "{0}_{1}_{2}.evtx" -f (get-date -f "yyyyMMdd"),$log.CSName,$log.FileName.Replace(" ","")

  #map a PSDrive with credentials
  New-PSDrive -name B -PSProvider Filesystem -Root \\chi-fp01\it -Credential $using:cred | Out-Null

  #backup path must be something Windows can see like a UNC
  $backup = join-path (get-psdrive B).root $file
  write-host "Backing up to $backup" -ForegroundColor cyan
  $r = $log | Invoke-WmiMethod -Name BackupEventlog -ArgumentList $backup
  if ($r.returnValue -eq 0) {
    Get-Item $backup
  }
  else {
   Throw "Backup failed with returnvalue $($r.returnvalue)"
  }

 } -ComputerName $computers