Generators and Motors
[Home] - [HELP] - [Forums] - [Articles] - [Photo Gallery] - [Groups] - [Chat] - [Classified Ads] - [Subscribe] - [Links] - [Books] - [Sponsors] - [Tools]

Go Back   SmokStak > SmokStak® Vintage Electrical Equipment > Generators & Motors General Discussion
Forgot Password? Join Us!

Notices

Generators & Motors General Discussion Antique Generators, Light Plants and Old Electric Motors: Questions and answers about restoring and showing old power generation systems.

Generators & Motors General Discussion

Auto transfer switch humming - maintenance?


Hi guys, My Kohler 104amp 240v auto transfer switch hums quite a bit on utility power. When powered...

this thread has 14 replies and has been viewed 1833 times

Reply
 
Thread Tools Display Modes
  #1  
Old 09-09-2011, 03:59 PM
Steve Jags Steve Jags is offline
Registered-II
 
Join Date: Nov 2006
Location: Stamford, CT
Posts: 106
Thanks: 9
Thanked 2 Times in 2 Posts
Default Auto transfer switch humming - maintenance?

Hi guys,
My Kohler 104amp 240v auto transfer switch hums quite a bit on utility power. When powered by the genset the hum goes away. This leads me to believe it’s the contacts for the main power. Do these need cleaning or some other type of maintenance? I imagine that they must collect dust and ferrous particles over time. Fortunately for me the main breaker is before the transfer switch so I can completely shut down the power to work on this. What is the best way to inspect/clean these?
Thanks,
Reply With Quote
Sponsored Links
  #2  
Old 09-09-2011, 05:58 PM
Tony Rye Tony Rye is offline
Subscriber
 
Join Date: Aug 2008
Location: Mobile, Alabama
Posts: 269
Thanks: 11
Thanked 49 Times in 47 Posts
Default Re: Auto transfer switch humming - maintenance?

don't know if yours is like some i have seen .the coil that SW. the con tack may be out of adj. if you have a service manual it will show you how to set them hope this helps
Reply With Quote
  #3  
Old 09-09-2011, 06:54 PM
Jack Hottel Jack Hottel is offline
Subscriber
 
Join Date: Oct 2005
Location: Haymarket, Virginia, USA
Posts: 681
Thanks: 182
Thanked 298 Times in 202 Posts
Default Re: Auto transfer switch humming - maintenance?

If it does not normally hum then it sounds like a coil is energised. Maybe the limit switches that disconnect the switch actuation coil after transfer are misadjusted and not opening when the transfer is complete. Shut off the power and go feeling for a warm coil. If you find one then investigate to see if it is energised when it should not be.
Good luck,
Jack Hottel
Reply With Quote
  #4  
Old 09-09-2011, 08:39 PM
Gunny Gunny is offline
Subscriber
 
Join Date: Feb 2005
Location: North Carolina
Posts: 3,112
Thanks: 743
Thanked 1,168 Times in 770 Posts
Default Re: Auto transfer switch humming - maintenance?

Probably, the 2 faces of the normal side holding coil are not mating due to dirt, dust or some other crud finding its way in there.


Power it down, disassemble the coil, clean it and while there, clean the contacts.
Reply With Quote
  #5  
Old 09-10-2011, 09:04 PM
Steve Jags Steve Jags is offline
Registered-II
 
Join Date: Nov 2006
Location: Stamford, CT
Posts: 106
Thanks: 9
Thanked 2 Times in 2 Posts
Default Re: Auto transfer switch humming - maintenance?

Quote:
Originally Posted by Gunny View Post
Probably, the 2 faces of the normal side holding coil are not mating due to dirt, dust or some other crud finding its way in there.


Power it down, disassemble the coil, clean it and while there, clean the contacts.
I'm sure this is my problem but I'll check for a warm coil anyway.

Gunny, how simple is it to disassemble this? unfortunately I do not have a manual.
Reply With Quote
  #6  
Old 09-10-2011, 09:27 PM
Power Power is offline
Registered-III
 
Join Date: Aug 2011
Location: Hightax, USA
Posts: 2,688
Thanks: 655
Thanked 1,320 Times in 876 Posts
Default Re: Auto transfer switch humming - maintenance?

No big deal - if you are mechanically bent. I make notes, label everything and take colored markers and run lines down pieces so I get everything back the same way. The long screw went in that hole - the spring is on top of the contacts with the small side up ---
Gunny is right on target (pun intended) most of time it is dirt on pole pieces.
Reply With Quote
  #7  
Old 09-11-2011, 07:54 AM
Gunny Gunny is offline
Subscriber
 
Join Date: Feb 2005
Location: North Carolina
Posts: 3,112
Thanks: 743
Thanked 1,168 Times in 770 Posts
Default Re: Auto transfer switch humming - maintenance?

I worked for Kohler for a while and still have some manuals in PDF format. Trouble is, not sure where I filed them. If I find the manual for your switch, I'll send it.

Kohler used a lot of ASCO switches, might take a look on their web site. They used their own model numbers and sometimes changed a few things. Look for visuals, if it looks like yours, it should be close enough to be of use.

Those things are pretty simple, no surprises, someone of average capabilities can tackle this without any problems.
Reply With Quote
  #8  
Old 09-11-2011, 09:07 AM
Elden DuRand's Avatar
Elden DuRand Elden DuRand is offline
Subscriber
 
Join Date: Nov 2004
Location: Port St. Joe, Florida USA
Posts: 5,658
Images: 6
Thanks: 7,141
Thanked 3,911 Times in 1,728 Posts
Default Re: Auto transfer switch humming - maintenance?

Quote:
Originally Posted by Power View Post
No big deal - if you are mechanically bent.
....................................snip.......... ...................
Power:

I can't help it! ....... Because I'm mechanically bent!

Also, if the relay is humming, maybe it forgot the words.

I will now go back underneath my rock.......

Take care - Elden
http://www.oldengine.org/members/durand
__________________
Take care - Elden
http://www.eldensengines.com
Reply With Quote
The Following 2 Users Say Thank You to Elden DuRand:
  #9  
Old 09-11-2011, 09:30 AM
Billy J Shafer's Avatar
Billy J Shafer Billy J Shafer is offline
Subscriber
 
Join Date: Nov 2004
Location: Centerville, Texas
Posts: 10,882
Thanks: 4,793
Thanked 7,995 Times in 3,830 Posts
Default Re: Auto transfer switch humming - maintenance?

Most Kohlers I worked on were ASCOs. Simple to work on.



I have been bent for a long time.
Reply With Quote
  #10  
Old 09-11-2011, 10:27 AM
Arkie Arkie is offline
Registered-III
 
Join Date: Sep 2009
Location: Oklahoma USA
Posts: 911
Thanks: 2
Thanked 202 Times in 188 Posts
Default Re: Auto transfer switch humming - maintenance?

Quote:
Originally Posted by Gunny View Post
Probably, the 2 faces of the normal side holding coil are not mating due to dirt, dust or some other crud finding its way in there.


Power it down, disassemble the coil, clean it and while there, clean the contacts.
The laminated armature in the center of the coil usually gets rust or dust on the laminations. Sometimes you can give it a shot of air when not energized, and this will correct or make worse or change the sound, then if no good try a shot of contact cleaner (make sure it's non-flammable contact cleaner around the arm then operate by hand few times and if still noisy, the armature (moving part) will need removed and thourghly cleaned and it's mating surface. Usually it's straight forward once you start because it's the same procedure required for replacing a bad normal or emergency coil.
When you have it apart if the laminations on the moving armature are starting to rust, clean the armature good, then use a non-dirt attracting type cleaner and rust inhibitor., so as to prevent a quick comeback of the surface rusting.

Just a small nat's bristle or small grain under the armature of sand will cause what you describe.
Reply With Quote
  #11  
Old 09-13-2011, 04:34 AM
F. Moore F. Moore is offline
Registered-I
 
Join Date: Oct 2006
Location: Farmville,NC
Posts: 64
Thanks: 13
Thanked 3 Times in 3 Posts
Default Re: Auto transfer switch humming - maintenance?

I agree, it's probaly crud inside the contactor. I did a start-up on an Onan/Cummins and it hummed a bunch on generator power but not on Utility power. The contractor that installed it drilled through the top of the ATS cabinet and the shavings fell inside the switch. When the contactor energized it would not allow it to fully engage the flat surface of the lamination and had an inductance hum. Non-warrantable failure, end user got stuck with the bill.
Reply With Quote
  #12  
Old 09-13-2011, 07:49 AM
Arkie Arkie is offline
Registered-III
 
Join Date: Sep 2009
Location: Oklahoma USA
Posts: 911
Thanks: 2
Thanked 202 Times in 188 Posts
Default Re: Auto transfer switch humming - maintenance?

Quote:
Originally Posted by F. Moore View Post
I agree, it's probaly crud inside the contactor. I did a start-up on an Onan/Cummins and it hummed a bunch on generator power but not on Utility power. The contractor that installed it drilled through the top of the ATS cabinet and the shavings fell inside the switch. When the contactor energized it would not allow it to fully engage the flat surface of the lamination and had an inductance hum. Non-warrantable failure, end user got stuck with the bill.
The flat surfaces of the contactor is USUALLY where the Carpenter Bee sound (wood bee) is being generated. But the foreign objects (dust, smiggens, and nat bristles, rust, dirty enviroment) may be down inside and not upon top preventing full engaugement.
Reply With Quote
  #13  
Old 09-13-2011, 08:22 AM
Steve Jags Steve Jags is offline
Registered-II
 
Join Date: Nov 2006
Location: Stamford, CT
Posts: 106
Thanks: 9
Thanked 2 Times in 2 Posts
Default Re: Auto transfer switch humming - maintenance?

Hopefully this weekend I'll be able to take a closer look.
Reply With Quote
  #14  
Old 09-13-2011, 10:35 AM
BergmanJ BergmanJ is offline
Registered-II
 
Join Date: Apr 2005
Location: Duluth, Minnesota USA
Posts: 361
Thanks: 259
Thanked 165 Times in 111 Posts
Default Re: Auto transfer switch humming - maintenance?

"I have been bent for a long time." OUCH!!!!
Reply With Quote
  #15  
Old 09-13-2011, 04:04 PM
Arkie Arkie is offline
Registered-III
 
Join Date: Sep 2009
Location: Oklahoma USA
Posts: 911
Thanks: 2
Thanked 202 Times in 188 Posts
Default Re: Auto transfer switch humming - maintenance?

Quote:
Originally Posted by BergmanJ View Post
"I have been bent for a long time." OUCH!!!!
Huh!!!!!!!!!!!!
Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Transfer Switch? Cruiser Onan Generators 4 03-10-2011 10:14 PM
Help: Suggestions where Fleetwood put my AC 'auto' transfer relay? StealthTaffer Onan Generators 0 01-08-2011 08:05 PM
Transfer Switch don-mar Onan Generators 8 01-25-2010 08:09 PM
DJC transfer switch? DieselCJ Onan Generators 8 07-04-2009 12:16 PM
Transfer switch milmaint Onan Generators 6 01-15-2009 12:16 AM


All times are GMT -4. The time now is 06:42 AM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark
A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2014 by Harry Matthews
P.O. Box 5612 - Sarasota, FL 34277