Hi Bill -
Thanks, this is helpful info. Do you know how to calculate or approximate how we would keep the unbalanced voltage to less than 3%? I guess I need to check out ANSI/C84.1-2011 but I thought maybe there are some ballpark rules of thumb. Thanks, August *August Goers* Luminalt Energy Corporation o: 415.641.4000 m: 415.559.1525 *From:* [email protected] [mailto: [email protected]] *On Behalf Of *Bill Brooks *Sent:* Friday, October 18, 2013 9:27 AM *To:* 'RE-wrenches' *Subject:* Re: [RE-wrenches] smaller 3-phase commercial inverters Marco, Besides the good responses you have already received, 20-30kW, 480V machines are really targeting larger installations that would be on facilities with 480V. I would generally not build a system with 480V inverters on a 208V service. For large systems, there are large inverters running at 208V, for small systems there are plenty of single-phase units that would work just fine. Incidentally, read the new NEC 705.100 in the 2014 code. It clarifies that utilities should not be disallowing single-phase units on a 3-phase service. The typical utility concerns do not understand how the equipment works. *(A) Single Phase. *Single-phase inverters for hybrid systems and ac modules in interactive hybrid systems shall be connected to three-phase power systems in order to limit unbalanced voltages to not more than 3 percent. Informational Note: For utility-interactive single-phase inverters, unbalanced voltages can be minimized by the same methods that are used for single-phase loads on a three- phase power system. See ANSI/C84.1-2011, *Electric Power Systems* *and Equipment — Voltage Ratings (60 Hertz)*. This is a huge change from the way it was previously written. You can thank me next time I see you with a beer. This was my proposal. Bill. *From:* [email protected] [ mailto:[email protected]<[email protected]>] *On Behalf Of *Marco Mangelsdorf *Sent:* Thursday, October 17, 2013 9:31 PM *To:* 'RE-wrenches' *Subject:* [RE-wrenches] smaller 3-phase commercial inverters Yeah, lots more choices out there in the 10+ to 30 kW range….but pretty much all of the larger capacity models only come at 480V. Anyone know why? We have way more 120/208V applications here in Hawaii than 277/480. marco Chris Mason wrote: >SMA just came out with their Sunny Tripower line for the US. Yes those are interesting. But they are only for 480 Wye, not 240 Delta..... Is the Fronius 11.4-3 the only 3-phase inverter that can work with 240 3-phase with a hi-leg (stinger)?
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