In order to set the PowerShellMaxConcurrency value we need to to edit the default Throttling policy on the server.
To edit the value we first need to find the name of the default Policy by running the following cmdlet:
Get-ThrottlingPolicy |fl
Once you run the cmdlet find the Policy name under Name: and copy it.
To set the value run the following cmdlet:
Set-ThrottlingPolicy -PowerShellMaxConcurrency 1000
The cmdlet will ask for the policy name:
Set-ThrottlingPolicy at command pipeline position 1
Supply values for the following parameters:
Identity: DefaultThrottlingPolicy_3d63448b-f3de-4822-9fd1-2148vv9e0ac9
All done.