bestred1 Report post Posted October 29, 2022 Simple question to those of you that have an Automatic Transfer Switch in your coach: Do they hum continuously while powered? My coach is old school, no ATS. I've bought one but have yet to install it. Have had 2nd thoughts as I've read numerous posts here and in other forums I follow, regarding reliability. In some cases people have reported annoying noise. Mine will be installed almost directly below where I lay my head at night and I'm a lite sleeper. With weather being nice right now, I may install it next week so this is my last concern. Share this post Link to post Share on other sites
wildebill308 Report post Posted October 30, 2022 My ATS doesn't make any noise outher than a clunk when it switches. Mine defaults to the generator. Bill Share this post Link to post Share on other sites
rayin Report post Posted October 30, 2022 If a switch hums it is likely due to burned or ill-fitting contacts. Any contacts/mating conductors must have a clean solid contact to eliminate as much resistance as possible. That is why you see the caution on RVing forums not to switch power sources when high-amperage appliances are running. That higher current burns contacts. Share this post Link to post Share on other sites
jleamont Report post Posted October 31, 2022 I’ve seen that model in action, no humming. I have heard certain models can be pronounced while others are quiet. As mentioned a fatigued unit can also be a contributing factor. If mounted in the basement you should be good on the noises if any are observed. Share this post Link to post Share on other sites
rls7201 Report post Posted October 31, 2022 (edited) Transfer switches (relays) hum when the armature and the iron core don't make full contact when in the closed position. Has nothing to do with the contacts. As far as reliability, they offer little problem. My 95 Bounder still has the OEM auto transfer switch. Richard Edited October 31, 2022 by rls7201 Share this post Link to post Share on other sites
rayin Report post Posted October 31, 2022 OK, thanks for the edification. Share this post Link to post Share on other sites
bestred1 Report post Posted February 15, 2023 I installed it shortly after this post and no hum. Works great! Thanks for the feedback! Share this post Link to post Share on other sites
gatorcq Report post Posted February 25, 2023 What you want is a Transfer Switch that is controlled by DC coils Share this post Link to post Share on other sites
