Don't worry about over voltage, 220/127 is pretty common. Most utilities run about 6% over voltage to allow for droop during high load and long delivery lines. Inverters will not suffer the same issue so it is will be fine. Also, high load single phase equipment is generally 208/240V so they are designed for a wide range of voltage. Bump your SIs to 220v and you won't have any issues.
On Thu, Jul 3, 2014 at 10:45 AM, William Miller <will...@millersolar.com> wrote: > Chris: > > > > 1. The house is at the end of a 200 foot feeder. The feeder is > generous, 300 MCM, but depending on the use at the house, there will be > some voltage drop. At 205 the drop is 1.44%, not bad. > > 2. Your idea of increasing the voltage at the source is intriguing. > Thank you for that. These are Sunny Island inverters and I assume they > have a voltage adjust. I presume if I adjust the 208 upwards I also adjust > the 120 as well. I would need to be careful to not adjust this too much. > > 3. There are 120 and 208 loads at the power house so I can’t get to > enthusiastic about overcoming voltage drop because I would over voltage at > the power house. > > > > Thanks! > > > > William > > > > > > > > [image: Gradient Cap_mini] > Lic 773985 > millersolar.com <http://www.millersolar.com/> > 805-438-5600 > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On > Behalf Of *Chris Mason > *Sent:* Thursday, July 03, 2014 3:31 AM > *To:* RE-wrenches > *Subject:* Re: [RE-wrenches] 208 volt off-grid well pump > > > > William, > > If your voltage at the pump is 205 voltage at no load, it is not a cable > issue, your source of power is at too low a voltage. Voltage drop is > proportional to current, no current, no voltage drop. > > Most 208V system are run at about 215v, to allow for some drop and to > facilitate 240v equipment. If there is a way to tweak your inverter output > voltage to 220v, you will save yourself some problems. > > The island of St. Maarten runs at 220v 3 phase (127V single phase) and > everyone used US made equipment, so it will not cause problems. > > If your pump was designed for single phase 240V, you can install a > buck/boost transformer, it is done all the time for exactly this reason. > The phase angle is not relevant when you are talking about two phases. > > > > On Thu, Jul 3, 2014 at 2:33 AM, William Miller <will...@millersolar.com> > wrote: > > Friends: > > > > About two months ago I inquired of this forum about complications that > might result from running a residence on a 208 volt 3 phase system. One > respondent indicated that motors might be affected. Sure enough the owner > is having problems with the well pump. It is tripping circuit breakers. > > > > I conferred with a pump specialist. The information I was given is that > the standard single phase pump is rated at 230 VAC and can operate at +/- > 10%. This means the voltage must be at least 207 VAC. > > > > The measured no load voltage at the pump is 205 and loaded is 200. The > leads to the pump are 10 AWG and this is too small for the well pump > (guessing it is 2 to 3 horsepower). Even after I upgrade the wire the best > I can do is 204-ish. > > > > Can I install a transformer to increase the voltage? Would the phase > angle at the secondary become 180°? > > > > Thanks in advance. > > > > William > > > > > > [image: Gradient Cap_mini] > Lic 773985 > millersolar.com <http://www.millersolar.com/> > 805-438-5600 > > > > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > > > > -- > > Chris Mason > > NABCEP Certified Solar PV Installer™ > > Solar Design Engineer > > Generac Generators Industrial technician > > > > www.cometsolar.com <http://www.cometenergysystems.com> > > 264.235.5670 > > 869.662.5670 > > Skype: netconcepts > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org > > > -- Chris Mason NABCEP Certified Solar PV Installer™ Solar Design Engineer Generac Generators Industrial technician www.cometsolar.com <http://www.cometenergysystems.com> 264.235.5670 869.662.5670 Skype: netconcepts
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