# ATS testing



## slydeman (Mar 11, 2013)

We do monthly generator and ATS testing at our facility for 30 minutes. Every 3 years our engineers require us to run them for 4 hours under building load. Since in most older switches, the timers top out at 30 minutes, this requires us to drop power to the ATS to extend the test.

My standard procedure was to initiate the test from the ATS and then drop power. I got some feedback from another wireman that was assisting me on these tests that he was just dropping power to better simulate an outage. I stated that I disagreed with this because this would bypass safety features that are programmed in to some of them such as presignal timers for elevator capture or others.

Any feedback on this from anyone with generator experience?


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## Bbsound (Dec 16, 2011)

Killing the normal feed is the only way to test the voltage sensing electronics in the ATS. 
if you are worried about elevators, have people call them to a floor and hold them to start the test.


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## BBQ (Nov 16, 2010)

I have seen things test fine and then not work properly during a real outage. 

The only way I would test is by dropping power ahead of the ATS.


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## 64pvolvo1800 (Jan 29, 2013)

slydeman said:


> We do monthly generator and ATS testing at our facility for 30 minutes. Every 3 years our engineers require us to run them for 4 hours under building load. Since in most older switches, the timers top out at 30 minutes, this requires us to drop power to the ATS to extend the test.
> 
> My standard procedure was to initiate the test from the ATS and then drop power. I got some feedback from another wireman that was assisting me on these tests that he was just dropping power to better simulate an outage. I stated that I disagreed with this because this would bypass safety features that are programmed in to some of them such as presignal timers for elevator capture or others.
> 
> Any feedback on this from anyone with generator experience?


The Proof is in the Pudding! 
Most ATS's did not have a std presignal. Post your model/serial and we can tell you exactly what you have. I personally believe the only true test is an outage. Pull the main. 
You also have the option, depending on the ATS, of installing a maintained position test switch to keep the unit on line. Do NOT do this without research however. In most instances you need to use a remote test input instead of swapping the switch. In the case of a generator failure while exercising, you do want a retransfer. Unless the ATS is constructed/programmed to ignore the test switch during this condition, you could set yourself up to sit in the dark until you get back to the ATS. 

Asco makes a very good product and everything they made in the last 10-15 years practically has these options, ie 300 series.


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## Southeast Power (Jan 18, 2009)

Unless you do a full utility fail test, you are just exercising. 

If that's all you want, you are good to go.


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## wildleg (Apr 12, 2009)

if you want something to work when you need it, you need to test it under the real field conditions (I agree with what everyone above said). kill the utility power and know it's going to work. Do you want people stuck in the elevators under real conditions ? Knowing that all the systems are functioning correctly is the whole point.


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## 64pvolvo1800 (Jan 29, 2013)

One additional note toconsider: 
Most of the problems associated with testing involve tripped breakers on REtransfer. Depending on the ATS type, the contorl may have an in-phase monitor or an open programmed transition which stops between sources for a couple seconds. If it is old and has neither option, then any heavily inductive loads such as elevators, transformers, chillers, and motors at all, have a much higher probability of tripping branch breakers during retransfer. 

Ever have this happen?


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