[BC] AC Voltage Drop

[Phil Alexander]

The big problem with open delta is a sometimes high harmonic content.
(Depends on loads on primary side as well as secondary, and VAR
correction on line plus regulator setting etc.)

The bottom line is that although the manufacturer of that shiny new
5 kW box may demand you connect it to a wye or closed delta source,
the cost of conversion is at your expense unless you can measure
a problem. In this case you would need to show a harmonic content
above 1% THD frequently on at least one phase. Otherwise the utility
can rightly say their drop to you meets all standards of good practice,
and BTW here's a bushel of sand you can go pound until you bring them
evidence they are wrong. 

BEFORE YOU START MEASURING WITH A METER INTENDED FOR AUDIO, THERE ARE 
TWO PROBLEMS. First, it is a good way to fry your distortion analyzer 
unless you know EXACTLY what you are doing. Second, your test setup,
especially the means of voltage reduction, must not introduce 
distortion.

Phil Alexander, CSRE, AMD

-----Original Message-----
>From: Chris Gebhardt <chris at virtbiz.com>
>
>Well here is one reason why you may not want to play it that way.  Who 
>pays for it?   If the utility is having a problem delivering the voltage 
>that you're currently subscribed to, then they will pay to repair it. 
>In the course of the repair, you can tell them that while they're at it, 
>go ahead and drop a 208-Y instead of the 240-Delta.   If it turns out 
>that after an investigation the power they are supplying is fine, but 
>you still want to change over, then you'll likely pay for it.