ok hooked up power and the transfer switch makes a humming sound is that normal ? or is it bad ? or maybe need to clean contacts ?
i dont known anything about these help thanks john
:D :What tune is it humming?
Sounds like it is doing its job.
John
Maybe it doesn't know the words ???...Cable
Contactor-based transfer switches will hum when energized. There is basically an electromagnet inside, so you'll hear a 60hz hum.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
Sean is right again!
TOM
Click here to hear 60hz hum (http://upload.wikimedia.org/wikipedia/commons/a/ab/Mains_hum_60_Hz.ogg)
or copy/paste http://upload.wikimedia.org/wikipedia/commons/a/ab/Mains_hum_60_Hz.ogg into your browser.
Brian S.
hi tryed to open link would not work . ok when i plug in the shore line you hear a loud hum the switch came from the monaco factory
so it is for rv use. in the morning i can get the name & model # thanks john
I have had Tinnitus for 40 years so i hear a 60 hz hum or buzz all of the time.
John,
Is Costa Rica power grid 60 or 50 cycle? What cycle is transfer switch rated for? Jack
hi jack costa rica is 60 same as usa transfer switch is from usa what might be a proublum is most wireing in costa rica is 2 wire
not 3 wire like usa we do you copper ground poles mine is 6 ft under ground at first i used a 110 v cord to test outlets i think
i will plug it in to my 30 amp welder cable as that is 3 wire and see if it makes any difference but from what i see heer they do
hum ? thanks john
Perhaps I was not clear: The hum is normal. Unless you have symptoms of other problems with the ATS I would not worry about it.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)
If the hum is very loud, it may be loose laminations in the relay coil. Not much you can do except to be sure everything is tight within the box, especially the relay mounting. It's not dangerous, just a bit annoying sometimes.
ok thanks everyone i went and undid everything checked cleaned & tightend it all great the hum is normal so all is ok
thanks john
I disagree on hum being normal. First bus I used an ATS device (50A) to feed the AC distribution panel. Started to hum upon connection to shore power. Opened input breaker and reclosed hum stopped. As the hum became prevalent every time ATS was energized from shore power I did some thinking and poking. Replaced the contactor/coil assembly on one leg. The cause of the hum was a loose lamination in the core.
Yes a coil maybe energized to close the contactor but a loud hum is unsat. I worked in a big power plant for many years. Noises were tracked to the source and repaired.
These ATS units are in all the high end units and tolerance for loud noise is very low.
Can you make the noise stop by pressing on the coil? Does the noise stop if you apply pressure to the assembly internals? Obviously use a non conductive tool to do this check.
Thank God its not rocket science but only bus stuff that we can eventually fumble our way through.
Bill
Quote from: Bill B /bus on July 30, 2010, 08:52:54 AM
I disagree on hum being normal. ...
That depends on the loudness.
All 120vac contactors hum. Good engineering and manufacturing can make the hum as quiet as you'd like, even as to be inaudible to most people with normal hearing. However, the contactors typically used for RV ATS applications are not this quiet. These are reversing three-phase motor starters, so the design goals at the contactor manufacturer do not include "inaudible."
The ATS manufacturer can quiet these down a bit further by using vibration-isolating mounts for the contactors, non-metallic enclosures, and the like. But here again, most manufacturers do none of these things.
Without knowing how loud John's hum is, it's impossible to say whether he might have a coil with loose laminations. Moreover, even a barely audible hum can be amplified by the environment, for example by mounting the device to a resonant surface.
Quote... I worked in a big power plant for many years. Noises were tracked to the source and repaired.
I would submit that any hum that could be heard in a power plant would be very loud indeed. I have to assume that is not what we are discussing here; my impression is that this is the first time John has ever used such a contactor, and in such a case even the normal amount of 60hz hum can be unsettling. I would guess that if he removed his ATS and mounted it in a power plant, no one would hear it there.
QuoteThese ATS units are in all the high end units and tolerance for loud noise is very low.
Without knowing what make and model switch he has, it's hard to say it is "high end." RV transfer switches are commodity items, and many of them are made with inexpensive contactors. I include in that the two most popular brands, Iota and Progressive. The inexpensive contactors have a great degree of variability in manufacturing tolerances, and I've seen units that were barely audible and ones that would rattle your teeth out from the same batch. I've also seen units where the two contactors in the same enclosure had different sound levels. I don't think you'd have much success sending one back because the hum was too loud. High-end RV manufacturers sometimes use more expensive switches; more often they take care to mount the ATS where it will not be heard, such as next to the (also humming) inverter.
QuoteCan you make the noise stop by pressing on the coil? Does the noise stop if you apply pressure to the assembly internals? Obviously use a non conductive tool to do this check.
Only a few large ATS contactors have coils you could even access while they were operating to press on them. At best you might be able to press on the contact carrier. 50-amp and larger contactors often have fully enclosed coils.
One way to help resolve the question, though, would be this:
John, does the switch hum at the same volume whichever side you connect to power, or does one input hum louder than the other?
Also, can you tell us the make and model of the ATS? I can see if I can find out what contactors they are using.
-Sean
http://OurOdyssey.BlogSpot.com (http://ourodyssey.blogspot.com)