Ricoh should be able to connect you to technical support or an engineer. 3-Phase power is run only to certain zoning, i.e., industrial. If your able to get 3-phase your going to have to spend the money for additional electrical boxes and running the 3 phase lines through your shop.
I suggest contacting Ricoh and asking for a local sales rep. if you already don't have one. Equipment manufacturers are always willing to take you to other companies that are running the same machines that your interested in... you can gain a lot of honest insight about the machine after talking to a "real" end-user. When I previously purchase equipment with significant investment I always demand to see it operating in a production shop. This allows you to differentiate between the BS that a sales rep. will spew to sell the machine and what you can actually expect to get in a real world situation.
When using phase converters go digital, they are better. Also, its a must to get a voltage line conditioner and installing it between the phase converter and the machine. If you don't have a line conditioner your going to run into problems with print consistency. Highly recommend that you talk to a Ricoh engineer that is familiar with the particular machine your interested in and its setup requirements. In the past I've been able to get a conference call with engineer, sales rep. and an electrician... but this has been with Fujifilm... If you can do this, its your best bet.