Nik, It's been a few years since I've seen this... I have seen several cases of plug-in UPS and "surge protector" power-strips that were incompatible with the inverter. The symptoms were "tripping" and "singing". These were straight up incompatible and would "trip" or "sing" any time the inverter was running at any power level over about 1000 watts. There weren't any unrelated loads associated with the issues. Changing to any other model solved the problem. If these are plug-in models, I suggest taking a replacement with you and seeing if that trips under the same conditions.
Beyond that: You say their UPS systems are "tripping". Some background diagnostic info: Is the PV tied into the same distribution panel that the UPS and air handler are? How many UPS units are there? 120V or 240V? Is/are this/these local to each workstation or is/are this/these backing up one or more distribution circuits? How many of them are "tripping"? If these are local units, are the "tripping" units all on the same circuit or phase out of the distribution panel? What do you mean "tripping"? (i.e. Local UPS "beeps" and picks up the workstation or ?) How long does the "trip" last? (i.e. Just until the air handler motor is up to speed or ?) I'm guessing that these are workstation units. If the inverter is not dropping out, I suspect it is fine. If it's not an "incompatible" UPS issue, the air handler may be the source of the problem. Could be a failing capacitor or the motor might be dragging & spiking the neutral. They may have a bad breaker or bus on the air handler circuit, or a problem in the neutral. Neutral issues can be caused by a host of things. These things can be on the load circuit or in the feeder/bus. Undersized, loose connections, shared with other circuits.... I would make sure the air handler has a dedicated neutral. Another thing to look at is the relationship of the UPS circuit(s) to each other and the air handler circuit. If multiple UPS units are on the same circuit and these are on the same phase as the air handler, switch one or the other to the other phase and try it. If there happen to be two circuits feeding the UPS units, and these circuits share a neutral, tell the electrical engineer in charge that they need dedicated neutrals. If there are multiple 120V circuits sharing a neutral AND they happen to be on the same phase, switch one breaker to the opposite phase and then pull a dedicated neutral and charge them for it. An EE will argue that it's totally fine to share neutrals, but trust me, it's not. (The cheap-ass practice of sharing neutrals for multiple 120V circuits is complete BS. In circuits with inductive loads that don't have good filtering, this creates harmonic distortion.) Good luck and let us know what you find out. Matt Lafferty -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Richard L Ratico Sent: Tuesday, August 31, 2010 4:45 AM To: [email protected] Subject: Re: [RE-wrenches] phase issues with SB8000US Hi Nik, Some questions: Is this a 3 phase service? Details on the UPS; brand, kVA, age? Breaker sizes for the circuit(s) supplying the UPS and fan? Details on the air conditioning system and fan. Are they powered through the UPS? Dick Ratico Solarwind Electric --- You wrote: Wrenchers, We installed our first SunnyBoy 8000 this month. The customer (happens to be electrical engineer) is complaining that their computer UPS systems are tripping whenever the air conditioner (with 120V fan) comes on. This didn't happen before commissioning the solar system and it doesn't happen when the inverter is disconnected. So, of course, they suspect the inverter is the culprit. The theory being that the inverter itself is going out of phase when one of the legs is loaded down momentarily. So far, SMA tech support is not agreeing. They are blaming the problem on the unbalanced loads and/or the UPS systems. Their latest solution is to move the UPS systems to the other leg. Not surprisingly, the customer is not impressed with this game of Kick the Can Down the Road. The inverter does not drop the grid, nor display any error codes when this happens. This is a 200A, 240V service. The 120V fan draws about 10A continuously, 40A surge. Anybody else with similar experiences? Suggestions? Thanks Nik -- Nicholas Ponzio NABCEP Certified Solar PV Installer Building Energy 1570 South Brownell Road Williston, VT 05495 t: 802-859-3384 x15 f: 802-658-3982 c: 802-365-1973 http://www.BuildingEnergyVT.com _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org --- end of quote --- _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
