Set All VMs with a name as backup as being in maintenance mode for 20 minutes:
Get-VM backup* | Enable-OMMaintenance -MaintenanceTime 20 Name Health ResourceKind Description ---- ------ ------------ ----------- backup-089e13fd-7d7a-0 Grey VirtualMachine backup-d90e0b39-2618-0 Grey VirtualMachine backup-e48ca842-316a-0 Grey VirtualMachine backup-77da3713-919a-0 Grey VirtualMachine backup-c32f4da8-86c4-0 Grey VirtualMachine backup-c3fcb95c-cfe2-0 Grey VirtualMachine backup-4318bb1e-614a-0 Grey VirtualMachine