[RE-wrenches] phase issues with SB8000US

[Darryl Thayer]

It sure sounds like the surge is pushing the voltage around.  I susspect that the AC is causing voltage sag and the UPS is tripping off this low voltage.  I thought if the SB8000 used a neutral connection it was not supposed to get pushed off center.  The most puzzeling thing is why did it not do this before?  
Perhaps the UPS is just set to sensitive, it needs replacement?
1) Are the AC and the UPS pluged into the same outlet as before?  
2) Is it possible some breakers were moved to install the SB and at that time the AC got put on the same leg ac the UPS?  
3) Get a plug-in circuit tested and test the line impedence.  (this is a tester that puts small surges on the line and tells if the circuit impedence is sufficently low.) I think they go by the name circuit quality tester.
4) Look at the service connections, is there any discoloration? signs of heating?  
5) use your "Fox and Hound" to trace the outlets back to the service panel and identify the breakers and Legs of the AC and UPS 
6) Test the line voltage with the AC on and off to see if it is low.
7) Use you Max Min on your voltage meter to test the volt drop during start up.  

 I have seen things on standalone like this, but one would assume the grid would stabilize the voltage.  I have seen burned panels and lugs and meter socket burning due to line connections.     

If the UPS and the AC were on different legs, The AC load could drop the voltage but the UPS would not sense this being on the other leg.  Perhaps the SB is causing both legs to drop.  Ask SB if it is OK to disconnect the neutral, keep the ground.  
Darryl
--- On Tue, 8/31/10, Richard L Ratico <Richard.L.Ratico at VALLEY.NET> wrote:

> From: Richard L Ratico <Richard.L.Ratico at VALLEY.NET>
> Subject: Re: [RE-wrenches] phase issues with SB8000US
> To: re-wrenches at lists.re-wrenches.org
> Date: Tuesday, August 31, 2010, 6:44 AM
> 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
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