Recently one of the farms I work with got some additional servers joined to the farm. Rather than provisioning another WFE, we were expanding some of the back-end capacity. The Search Admin was running on a WFE, and we wanted to move search off to some dedicated servers. Here is the PowerShell script for moving Search Admin:
$SSA = Get-SPEnterpriseSearchServiceApplication "Current Search Service App"
$SA = Get-SPEnterpriseSearchAdministrationComponent -SearchApplication $SSA
$SA | Set-SPEnterpriseSearchAdministrationComponent -SearchServiceInstance NewServerName –Force
After moving the Search Admin you’ll want to kick start the crawlers with the following:
And as easy as that you can move search admin off to a new server!