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#38283 - 05/19/04 10:23 PM Emergency Generator Not Shutting Off  
Frank Cinker  Offline
Member
Joined: Jul 2001
Posts: 311
Pennsylvania
What is the most common cause of an emergency generator not shutting off after normal power is restored? Could it be something hanging up in the transfer switch?


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#38284 - 05/19/04 10:27 PM Re: Emergency Generator Not Shutting Off  
Attic Rat  Offline
Member
Joined: Dec 2003
Posts: 524
Bergen Co.,N.J. USA
...Is there a latching relay??


.."if it ain't fixed,don't break it...call a Licensed Electrician"

#38285 - 05/19/04 10:29 PM Re: Emergency Generator Not Shutting Off  
Frank Cinker  Offline
Member
Joined: Jul 2001
Posts: 311
Pennsylvania
I'm not certain, please explain.


#38286 - 05/19/04 10:51 PM Re: Emergency Generator Not Shutting Off  
Ralpha494  Offline
Member
Joined: May 2004
Posts: 73
Pewaukee,WI,USA
Some have a time delay so you have to have power restored for a pre-determined time. It could also not be recognizing the return of normal power. Who knows? It might not be an automatic.


#38287 - 05/19/04 10:56 PM Re: Emergency Generator Not Shutting Off  
Frank Cinker  Offline
Member
Joined: Jul 2001
Posts: 311
Pennsylvania
I'm going back to it early tomorrow morning. I'm also going to check for stable utility power. I've just read if utility power is not stable it will not switch back.


#38288 - 05/19/04 10:58 PM Re: Emergency Generator Not Shutting Off  
fla sparkey  Offline
Member
Joined: Aug 2002
Posts: 47
Winter Haven, Florida USA
You don't say if this is a service call or a new install. I would get the manual out and be sure the clock is programmed correctly and the dip switches are set right. Check the wiring diagrams too.


#38289 - 05/19/04 11:23 PM Re: Emergency Generator Not Shutting Off  
George Corron  Offline
Member
Joined: May 2001
Posts: 717
Lorton, Va USA
You may also want to check your return to normal delays (could be extended, I prefer 5 minutes minimum) and your cool down cycle, I prefer 15 minutes on larger units of over 100 kw. I have seen factory defaults of 1/2 hour each meaning an hour for retransfer and cool down, IOW it may be shutting down, just taking one heck of a long time to do it, some customers don't understand these things and panic.


#38290 - 05/20/04 05:26 AM Re: Emergency Generator Not Shutting Off  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
We have had two very new (less than a year) Onan transfer switches cause generators to run when normal power was fin.

Both times a electronic board in the ATS went bad.

One Generator ran for 126 hours the other for TWO WEEKS! they where natural gas units so fuel was not an issue.


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#38291 - 05/20/04 07:40 AM Re: Emergency Generator Not Shutting Off  
Ron  Offline
Member
Joined: Mar 2002
Posts: 582
White Plains, NY
I also agree that it is probably a relay or control board.

Bob,
Were these nat. gas units life safety? Do they allow nat. gas units for life safety in your area?


Ron

#38292 - 05/20/04 07:54 AM Re: Emergency Generator Not Shutting Off  
electure  Offline


Member
Joined: Dec 2000
Posts: 4,260
Fullerton, CA USA
...Well, we had a customer who put his in "test", and left it on all weekend, then couldn't figure out why it didn't turn off [Linked Image]


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