Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Sven and Kristi on December 21, 2016, 02:04:59 pm

Title: ATS hum
Post by: Sven and Kristi on December 21, 2016, 02:04:59 pm
I've tried insulating the sound from the ATS under the bed with limited success and am considering re-locating it and the surge protector to the utility bay to that area  where the cord and hose is normally stowed.  After studying the electrical diagram, it doesn't look like it would take an electrical genius.  Has anyone done this?
Title: Re: ATS hum
Post by: Pamela & Mike on December 21, 2016, 02:37:30 pm
Sven,

The A/C coils do cause some humming because that is just there nature. Was told by an old timer that worked on my crew that the hum was caused because the electric molecules are square when they leave the generator, as they travel down the round wire the corners get knocked off and thus you have a hum.  Now back on task.  If you go with a new style ATS with a D/C coil that should stop your hum and will work just fine as there are others that have swapped to a D/C system and are pleased. You can also change out to a manual switch which several have done with great success.  Doing it this way you don't have as big of a job of moving wiring.

Will your plan work? Yes, your big thing is going to be pulling wire and finding a place to mount your ATS that is out of the way but still accessible.

Pamela & Mike

Title: Re: ATS hum
Post by: Mike Leary (RIP) on December 21, 2016, 02:55:36 pm
  You can also change out to a manual switch which several have done with great success.
Not only the hum, but we've been parked next to some coaches where, for some reason, the gen set fired in the middle of the night!
Should we lose power, big deal, the Dometic switches to propane, that's all I care about, I hate warm beer!  ^.^d
Title: Re: ATS hum
Post by: Chuck & Jeannie on December 21, 2016, 03:28:51 pm
You're not the only ones that have been bugged by the hum...it is a common complaint.

30 amp transfer switch HUMMING! (http://www.foreforums.com/index.php?topic=28806.msg241381#msg241381)
Title: Re: ATS hum
Post by: Jim Frerichs on December 21, 2016, 04:39:46 pm
The best solution to a humming transfer box under the bed is to replace the trasfer switch with one that uses DC relays . The old ones were used AC powered relays and they do hum as they get older.

Jim
Title: Re: ATS hum
Post by: John Duld on December 21, 2016, 07:01:53 pm
Make sure all the connections are tight.
Not much else except change the switch.
Title: Re: ATS hum
Post by: rbark on December 21, 2016, 07:32:39 pm
And that the contacts are clean and make solid contact.
Title: Re: ATS hum
Post by: Carol & Scott on December 21, 2016, 08:11:50 pm
We have had a couple of different under bed ATSs that have hummed.  Some louder than others.  Last week powered down and removed the contacts and sprayed with computer air can both contacts.  There was quite a bit of residue/dust particles that were blown out.  This helped for a while.  Now the hum comes and goes.  Have thought about going to a marine type switch as well as the DC type.  I would be most interested in the DC type to keep the Automatic function.  That being said, when we installed our Magnum 2812 I was told that we could eliminate the ATS under the bed if we increased the size of one wire from the Inverter/converter to the breaker box.  Haven't done that either.  :D
Title: Re: ATS hum
Post by: FourTravelers on December 21, 2016, 08:13:17 pm
You could just try changing the contactor in the ATS, sounds as if the "shading coils" are loose or broken. These are the small rings around the laminated iron core of the contactor and are used to minimize the vibration of an AC contactor by reducing eddy currents in the iron core.
Title: Re: ATS hum
Post by: Sven and Kristi on December 21, 2016, 08:15:56 pm
Sven,

The A/C coils do cause some humming because that is just there nature. Was told by an old timer that worked on my crew that the hum was caused because the electric molecules are square when they leave the generator, as they travel down the round wire the corners get knocked off and thus you have a hum.  Now back on task.  If you go with a new style ATS with a D/C coil that should stop your hum and will work just fine as there are others that have swapped to a D/C system and are pleased. You can also change out to a manual switch which several have done with great success.  Doing it this way you don't have as big of a job of moving wiring.

Will your plan work? Yes, your big thing is going to be pulling wire and finding a place to mount your ATS that is out of the way but still accessible.

Pamela & Mike


I would have to look into how much a new style ATC would cost.  As far as the wiring is concerned, it is already there.  The end that is now attached to the incoming side of the ATC would go to the breaker panel and I would attach the relocated ATC to the other end, which is presently at the shore power connection.  The only additional wiring would be from the shore connection to the relocated surge protector (still connected to  the ATC) which would be next to the utility bay.  I need to know if my reasoning is faulty.
Title: Re: ATS hum
Post by: TulsaTrent on December 21, 2016, 11:23:07 pm
when we installed our Magnum 2812 I was told that we could eliminate the ATS under the bed if we increased the size of one wire from the Inverter/converter to the breaker box.
Scott,
 
I'm very interested. If you could find your notes, I would like to make that change. Which of my two ATS boxes do I remove?
 
I am going to install my EMS and one less box in that location would make it a bit easier!
 
Thanks,
 
Trent
Title: Re: ATS hum
Post by: Carol & Scott on December 22, 2016, 09:31:43 am
Trent -

Just sent  you a copy of some emails exchanged between Magnum and me a couple of years ago.

Title: Re: ATS hum
Post by: TulsaTrent on December 22, 2016, 11:08:51 am
Scott,
 
I was talking to them yesterday on a different issue.
 
Instead of holding, I chose the option to get a call back; that happened within 15 minutes. Second time I have talked to their Tech Support; they seem very knowledgeable about their products.
 
Thanks for the information,

Trent