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#38283 - 05/19/04 07:23 PM Emergency Generator Not Shutting Off
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: 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 07:27 PM Re: Emergency Generator Not Shutting Off
Attic Rat Offline
Member

Registered: 12/14/03
Posts: 530
Loc: Bergen Co.,N.J. USA
...Is there a latching relay??
_________________________
.."if it ain't fixed,don't break it...call a Licensed Electrician"

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#38285 - 05/19/04 07:29 PM Re: Emergency Generator Not Shutting Off
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: Pennsylvania
I'm not certain, please explain.

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#38286 - 05/19/04 07:51 PM Re: Emergency Generator Not Shutting Off
Ralpha494 Offline
Member

Registered: 05/19/04
Posts: 71
Loc: 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.

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#38287 - 05/19/04 07:56 PM Re: Emergency Generator Not Shutting Off
Frank Cinker Offline
Member

Registered: 07/29/01
Posts: 317
Loc: 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.

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#38288 - 05/19/04 07:58 PM Re: Emergency Generator Not Shutting Off
fla sparkey Offline
Member

Registered: 08/03/02
Posts: 46
Loc: 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.

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#38289 - 05/19/04 08:23 PM Re: Emergency Generator Not Shutting Off
George Corron Offline
Member

Registered: 05/16/01
Posts: 728
Loc: 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.

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#38290 - 05/20/04 02:26 AM Re: Emergency Generator Not Shutting Off
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: 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

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#38291 - 05/20/04 04:40 AM Re: Emergency Generator Not Shutting Off
Ron Offline
Member

Registered: 03/13/02
Posts: 577
Loc: 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

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

Member

Registered: 12/24/00
Posts: 4226
Loc: 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

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