# Stand-by generator-UPS set up/problem!



## Ljmcgregor (Apr 8, 2013)

The system set up is as follows:

Isolated b&b is powered solely by a UPS system (no mains power)
The UPS is charged by 3 wind turbines, a 60kva generator is on stand-by in auto mode to start up and charge the UPS, when the turbines are not running, and the UPS drops below a set voltage. 

The problem:

At the last service I switched off the main breaker and switched the gen from auto mode to off. After service I started the gen manually and closed the main breaker to check the load it was pulling. I switched the gen to off but it kept running at a lower frequency and voltage and only stopped when I switched off the main breaker. I did not do this again as I do not want to cause damage but I am unsure of what damage could be caused and do not understand what causes this. 
Is it due to a back feed from the UPS? 

Can anyone help me?


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## KRE (Nov 29, 2011)

The following is based upon an A/C genset.
Your ATS wiring is incorrect, and power from the turbines was motoring the gen set. Bulk of the time the line and load wiring is incorrectly reversed and that is the problem. I need to see a photo of your set up, then I can walk you threw the correct wiring. Or tell me what ATS you are using. Do not run the unit until it's wired correctly as if it goes in 120* out of phase you will, not maybe of if, you will destroy the coupling between the Engine and Alternator, fry the Alternator, or brake the engines crankshaft. If you have a turbo engine that fact might save you if the governor is set on the lazy side.

If you have a D/C gen-set feeding the UPS direct and no ATS, you have a diode or two bad.


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## Ljmcgregor (Apr 8, 2013)

The UPS and ATS are owned by the customer and were installed by a separate company and it was them who carried out all the installations and wiring, we just provided the gen. I believe my boss is getting in contact with the installer, I was just impatient to find a cause/solution. If I have it on the next service schedule I will try to get a photo of the transfer switch and panel. 

Cheers for the advice.


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## iowagold (Jan 22, 2020)

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