Create New Result Source for Federated Search using PowerShell

Add-PSSnapin microsoft.sharepoint.powershell -ErrorAction SilentlyContinue

#create a new result source at Search Service Application
$SearchServiceApplication = Get-SPEnterpriseSearchServiceApplication 
$FederationManager = New-Object Microsoft.Office.Server.Search.Administration.Query.FederationManager($SearchServiceApplication)

$SearchOwner = Get-SPEnterpriseSearchOwner -Level Ssa
$ResultSourceName ="Bing Search Result Source"

#For Site Level Result Source, Use:
#$SiteCollection = Get-SPSite $SiteUrl -ErrorAction SilentlyContinue
#$SearchOwner = Get-SPEnterpriseSearchOwner -Level SPSite -SPSite $SiteCollection

#Check if the Result Source is already exists
$ResultSource = $FederationManager.GetSourceByName($ResultSourceName,$SearchOwner)
if($ResultSource)
{
    $FederationManager.RemoveSource($ResultSource)
}

# create a new result source
$Query = "{SearchTerms}"

$ResultSource = $FederationManager.CreateSource($SearchOwner)
$ResultSource.Name = $ResultSourceName
$ResultSource.ConnectionUrlTemplate = "http://www.bing.com/search?q={searchTerms}&format=rss&Market=en-us"
$ResultSource.ProviderId = $FederationManager.ListProviders()['OpenSearch Provider'].Id
$ResultSource.CreateQueryTransform($queryProperties, $query)
$ResultSource.Commit()

Write-host Result Source: $ResultSourceName has been created successfully!