Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 01-11-2016, 10:31 AM   #1
Senior Member
Join Date: Feb 2013
Location: Sedona, AZ
Posts: 609
Hum from automatic transfer switch

Our automatic transfer switch is in a basement just below where DW sleeps. She hears a low hum or buzz from it, maybe all the time, maybe only some campgrounds, not sure. It bothers her. First, is this sound normal? Even if normal, any ideas for quieting it/muffling it?

Shell Bleiweiss
2014 1/2 Thor Challenger 37KT
Sedona, AZ
sbleiweiss is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 01-11-2016, 11:05 AM   #2
Senior Member
Podivin's Avatar

Join Date: Dec 2015
Posts: 397
If it's mounted directly to some hard surface in the basement, try mounting it so that there is rubber between the switch and whatever it's mounted to. Perhaps some rubber grommets that you can put the mounting screws/bolts through.
Or to test that theory, next time you're stopped remove it from its mount and just place it on something soft inside the basement. If DW can't hear it after that then you know changing the mount type (or location) will get you where you need to be.
My guess is that sound is traveling through the coach itself into you DW's pillow.

Podivin is offline   Reply With Quote
Old 01-11-2016, 11:23 AM   #3
Senior Member
falconman's Avatar

Join Date: Apr 2008
Location: On the Road
Posts: 625
If the humming has developed recently it could be a sign of dirt, moisture, or pitting of the contacts. After turning off all the power, including any inverter, you can remove the cover and clean the contacts with some electronic cleaner followed by compressed air. Take this opportunity to ensure that all wire connections are tight. If it continues you can try to isolate it from any hard surface as mentioned but it may need replacing if it bothers you to much. If you replace it as I had to do, make sure you get one with DC relays, much quieter than AC ones.
Dan & Arlene
2005 Monaco Dynasty Diamond IV
Chasing the good weather
falconman is offline   Reply With Quote
Old 01-11-2016, 12:57 PM   #4
Senior Member
530ktm's Avatar
Join Date: Dec 2014
Location: SoCal
Posts: 1,188
Mine hums, I believe that is rather normal also.
2014 Itasca Sunova 33C towing a Jeep TJ Wrangler
530ktm is offline   Reply With Quote
Old 01-11-2016, 01:06 PM   #5
Senior Member
Dr4Film's Avatar

Monaco Owners Club
Join Date: Oct 2009
Location: Varies Depending on The Weather
Posts: 7,542
Some ATS's use 120 VAC coils to switch the contacts which will hum. Others use 12 VDC coils to switch the contacts and those do not hum.

A couple of examples are two of the ESCO transfer switches.

The ESCO model ES50M-65N uses the 120 VAC coils whereas the ESCO model LPT50BRD uses 12 VDC coils.

If this is a new condition that just recently started then do as a previous poster suggested and clean up the ATS.

Dr4Film ----- Richard
2002 Monaco Windsor PBT 40Ft. (R HOME) - 30Ft. 2006 Pace Trailer (R JUNK). Trailer Has 06 VUE (R TOWD) 04 Victory Alen Ness Edition (R RYDE). Full-Timer for 14 Yr's BUT now a Part-Timer. Cummins ISC-350 With Banks Power Pack and Upgraded PRXB PacBrake.
Winter Home in Flagler Beach FL - Now Staying in Dansville NY for the Summer.
Dr4Film is offline   Reply With Quote
Old 01-11-2016, 01:17 PM   #6
Senior Member
mel s's Avatar
Join Date: Mar 2010
Posts: 8,546
Originally Posted by sbleiweiss View Post
Our automatic transfer switch is in a basement just below where DW sleeps. She hears a low hum or buzz from it, maybe all the time, maybe only some campgrounds, not sure. It bothers her. First, is this sound normal? Even if normal, any ideas for quieting it/muffling it?
Are you sure it is the transfer switch?

My inverter/charger, (which is next to my transfer switch in a basement compartment under the bedroom), always 'hums" when my coach is connected to shore power and/or when the generator is running.... and when it's producing 120VAC...but my transfer switch never has.
'96 Safari
mel s is offline   Reply With Quote
Old 01-11-2016, 01:29 PM   #7
Senior Member
Join Date: Nov 2005
Posts: 2,809
All good inputs here--AC driven contactors in x-fer switches tend to hum more as they get older, so go with DC next time. New hum/louder hum could be a sign that x-fer will fail sooner rather than later. The charge function on most inverters will cause a hum--not much you can do about that......

Old Scout
2003 40' MDTS
Garden Ridge, Texas
Old Scout is online now   Reply With Quote

transfer switch

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Thor Motor Coach recall - transfer switch PatricksPC Thor Industries Owner's Forum 5 11-10-2015 06:50 PM
Automatic transfer switch WDW Class A Motorhome Discussions 5 10-05-2015 11:34 AM
Automatic Transfer Switch? Shake Thor Industries Owner's Forum 23 06-27-2015 05:31 AM
Generator Transfer Switch? jb60 Class A Motorhome Discussions 36 10-28-2014 10:23 AM
Transfer Switch Problem rjmmonty Newmar Owner's Forum 7 03-23-2014 10:38 PM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 06:11 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.