The way you portrayed this guy left me with the impression that he wasn't very Hungry as a contractor.
Maybe it is me put I'd like a detailed plan of action or at the very least a check list before I started anything. What you intend to do is a lot of work, as such it would be best if attempts to minimize looses ends are made. On the other hand maybe I'm imagining bigger plants than you really have.I am switching from 240VAC 3-phase high leg delta to 208VAC 3-phase wye. Right now we have our machine transformer taps set to lower the incoming voltage being fed to the machine controls to around 200~210V since the 240V is to high. So by changing to 208V we will have to switch our taps around but it should cause no problems. If one or two machines arent happy on the lower voltage i could easily install a buck boost tx for that particular machine. I dont expect to have any issues but murphys law im sure will come into play.
Yes you could get some additional looses due to power varying with the square of current in resistive circuits. However you are only going from 240 to 208 volts AC so the change in current draw and thus looses in wiring shouldn't be that noticeable. It isn't like you are dropping from a 480 or 600 volt system.I guess the reason i thought the utility bill might change a little is from running lower voltage which in my mind means you need more amp draw to make the same amount of watts at the motors. More amp draw means slightly higher temps and less efficiency doesnt it? Maybe its a small enough amount to not really matter.
If you have any machinery with large AC heating loads you need to consider the possibility that those machines might have issues. Again in the power in the circuit varies with the square of the voltage in this case. So a small drop in voltage can impact things like mold machines, curing ovens or anything expecting to turn electrical power into heat.
I ran into a situation once where over the holidays some maintenance was done on some facility equipment which apparently resulted in changes to transformer taps. The manufacturing people came back to work and called in a problem on a solvent reduction oven "that wouldn't heat up". The machine obviously wouldn't reach set point but nothing obvious was wrong. The nominal voltage to the machine was slightly low, apparently the result of a couple of volts change in the line voltage. Obviously a machine that was running at the limits of its capability as it could not make set point due to a modest drop in line voltage.
In any event the point is sometimes unexpected problems show up.
Even if it doesn't solve your problem I'd have to believe that you are better off in the long run. At least from the maintenance standpoint I've found wild leg systems to be a pain in the you know what.Rcaffin - That is the main reason i have chosen to switch our power supply. Im hoping there is a problem with the current transformers and putting new transformers in place will eliminate that possibility. I could have just had them replaced with the same high leg delta setup that we have now but
1st we have no need for the high leg,
2nd its not likely but is possible the high leg is causing problems,
3rd unless i could prove that the current transformers are faulty i doubt the city would replace them just to see what happens.
So why not. If this doesnt solve anything at least i know the transformers arent the problem and i need to look elsewhere.