[RE-wrenches] RSD Troubleshooting Help

[rick at solshineenergy.com]

Wrenches,

I’m in need of some troubleshooting help on a newly installed system with rapid shutdown. System consists 2 SMA SB5.0-1 SP-US-41 (RSD version), RSD devices are APS RSD-S-PLC. Each SB is configured with two strings of 9. Modules are REC Alpha 360s. 

This system was fully functional for about 1 week before things went awry. Initial symptoms were that one of the two strings read 0V 0A on the display while the other read ~315V, 5A. The RSD devices output ~700mV each when in the off mode (a nice verification feature). I’m reading the correct voltage - 6.75V - on both strings when in off mode. Once the Sunny Boy comes on line I’m reading around 10V on the faulty string and the correct voltage - ~315V - on the other string. 

The above seems to indicate that each RSD is getting sufficient DC voltage from the module. Short of pulling each module and doing a visual check what else can I look at? How do you isolate a faulty RSD device?

And as luck would have it, everything is functional at the moment. 

Thanks,

rick brown
SolShine Energy Alternatives, LLC
Electrical & Solar Contracting Services
www.SolShineEnergy.com
Check, Virginia 24072
O: 540.235.3095
M: 540.808.9502

VA Class A Contractor Lic# 2705147660
VA Master Electrician Lic# 2710062762
VA Alternative Energy Systems Installer  
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