Converting one chassis configuration to another chassis configuration is not recommended as it may required multiple parts changes and you may face some fitment issues. To install a mid bay you may need to change the heatsink and air shroud. You can refer below link for the same [URL] you also need to ensure you are having a supported configuration. Connecting mid bay without rear bay is not supported. You can refer below link for supported backplane configuration.  [URL] To check power required for the config you can use "Enterprise Infrastructure Planning Tool" tool Link for same mentioned below.  [URL]#/ 
Hi Guys,   Quick question. we have a Dell PowerEdge R740xd with a setup of 12x 3.5inch HDD drives on the front bay, we want to add a midbay that will run 4x 2.5inch SSD drives.  My question is the server at the moment has 2x 1100W PSUs installed will these 2 PSUs be enough to run the added midbay as well
Dell PowerEgde R740xd Power supply