Well the computers in the same warehouse run at 110V from a line pulled out of the same 3 phase/208v panel, how is that any less complicated than make a 240v sub panel or just run a straight 240v line from the same 3P/208V panel ??
It is easy to get 120V from 208V 3 Phase. The potential between any two phases is 208V. The potential between any phase and the ground is 120V. Notice there is no 240V in the diagram.
Most premises either have 120V/208V 3 phase or 120V/240V single phase service (service = the connection to the power grid). The later is more common in residential and light business units. It is rare (although I guess not impossible) for a premise to have both types of service.
If you have 3 phase service then your options are 120V or 208V. Power supplies are more efficient at higher voltage so there is no reason to use 208V.
There is no good way to get 240V single phase from 208V 3 phase. I didn't say it was impossible but there is no benefit. Any tiny (<1%) efficiency by supplying the power supplies with 240V vs 208V will be eaten up by the efficiency losses in converting to 240V to begin with plus the cost associated with the install.
If the premises has 208 3 phase service then use 208V. It really is that simple.So once you accept you will be running at 208V it just comes down to how will you make the connection.
If you have enough 208V single phase outlets then simply plug the devices into the outlets directly and save the cost of the PDUs.
If you have some but not enough 208V single phase outlet then get enough 208V single phase PDUs to "share" one outlet with multiple devices.
If you only have 208V three phase outlets* then have an electrician install a sub panel to separate the 208V 3 phase branch into three 208V single phase drops with outlets.
* You can also get a PDU designed for 208V 3 phase but they are very expensive. Unless you are absolutely sure it is necessary I would just have electrician install the needed single phase outlets.
If you are going to only have one device per outlet there is no need for any PDU. Just use a power cord with the appropriate connectors and connect the device directly to the outlet.
I thought you needed a special cord to plug a 240 volt system to a regular 110volt device. If thats the case why did this guy go thru so much trouble to just to switch his system to 240?? I was told by an eletrician that cord for 110v are not the same for 240v. Im from South America and we use the same type of cord for 110v and 240v seems like here in America things are a bit different or at least thats what the 3 electricians talked to for the job said IDK.
The PDU isn't changing the voltage from 240 to 120. A PDU is just a fancy powerstrip. 120V in = 120V out, 208V in = 208V out*, 240V in = 240V out. Most computer electronics have a universal switching power supplies which can accept an input of anything from 110V to 240V. If you are using a 240V circuit you are powering the devices at 240V regardless of if you use a PDU or not. There is a different outlet for 120V and 208V/240V but that has nothing to do with a PDU.
* The one exception (kinda) is 208V 3 phase PDU. No computing equipment runs on 3 phase power so a 208V 3 phase PDU separates the three phase input into three single phase outputs. The voltage isn't changing though just the going from three phase to single phase.
A PDU is a power strip. Would you buy a power strip with 12 outlets and then connect one lamp to it? Why not just plug the lamp into the wall outlet the power strip is plugged into.
