[RE-wrenches] 208 volt off-grid well pump

[Chris Mason]

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 <william at 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
>
>
>
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-- 
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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