Note,
The enthusiasm about getting 3-phase to the shop is appreciated. However, please understand that this topic has been discussed at length by us stakeholders in the shop, and Josh Recave (our electrician).
That said, here is where the 3-phase situation stands, and where it is going:
We currently have three major machine tools which run on three-phase power- our horizontal mill, the large vertical mill, and the large lathe. Power to these machines is supplied by a diesel 3-phase 480V generator. We have a transformer to step it down to a lower voltage for the one machine that requires 220/208. While the generator has served us well for many years, it is very noisy, and it's capacity is already taxed when by our large mill.
In January, we will be taking delivery of a new "wheel" lathe to replace the New Haven. This new machine will be underserved by the existing generator. In addition to a new largest load, I have three other machines which I need to add to the 3-phase circuit: a new small lathe, a pedestal grinder that we've had kicking around, and the radial arm drill. The increased machine count and growing activity around #11 on the horizon, there is a much higher likelyhood of multiple simultaneous users, further taxing the capacity of the existing generator. Long story short, we need more 3-phase power, and we'd like it to be quieter.
That leaves two reasonable options- having CMP run 3-phase from their substation to the shop, or getting a shop sized phase converter. Before my time, CMP quoted a 3-phase supply, and due to poles needing to be changed and upgraded to hold the necessary hardware, it was a 5 figure quote. I don't know the exact number, as that discussion predates my involvement with the museum. As Bob put it, it wasn't affordable then, and isn't the cheapest option now. Individual phase converters for each machine might be cheaper to roll out over time, but the cumulative floor space losses, and number of machines which already need 3-phase make this a really unprofessional solution, and steer us towards a single phase converter large enough to meet the needs of the entire shop. A large phase converter is a reasonable and readily available option. Depending on the capacity and where it is placed (heated or unheated space), the cost will be up to $5K if new, less if used. We can get by with the generator we have for the time being, but hope to make a switch within a year. Josh is an active member of our planning for this upgrade, as he has the experience and credentials to tell us what we can/can't do, and where we can/can't put it. The machine tool voltage requirements and our existing transformer mean that very little will need to be done to switch over to a 220/240V supply. I stress that we are working very closely with a licensed electrician for both planning and execution, and his experience has been a tremendous asset to the museum over many years.
Hope this clarifies things.
