Electrical Buzz in panel

ajelinek · 06-25-2012, 06:59 AM

When we have any one of the lights turned on in our 3912LEV, the electrical panel has a terrible buzzing noise - it's not just a soft hum, it's very noticeable. We've had the camper now for a little over a year and it seems like it's getting worse. Happens both on battery OR auxilliary power. Can get it in for service in a week or so, but if it's a quick fix I can just do it myself.

There is also a terrible grinding noise in the electrical box when the furnace kicks on - seems like a bearing going out in the cooling fan in the box, but not sure. Any experiences in these areas?

Festus2 · 06-25-2012, 07:35 AM

It's not uncommon to hear a "quiet" hum coming from your converter when you turn on the lights; however, you shouldn't be hearing a loud buzz.

If your converter is a WFCO, you might try phoning their warranty service number at :
1-877-294-8997

Johnnyfry · 06-25-2012, 07:41 AM

This does not portend well, electrical panels are not designed to make any noises. Start by taking the cover off the panel and observing where the noise is emanating from.

Some possibilities:
AC-DC converter. These devices usually have a fan which activates with increasing load. They make a low hum. Fan could be clogged with dust or have a bad bearing
Faulty AC circuit breaker. These devices could hum or buzz if it is internally faulty.
Loose connection. If any of the screws holding wires on the breakers comes loose it could buzz under load.

Direct current does not usually make any sounds under these conditions, by aux power do you mean a generator?

Any of the above conditions can cause overheating and a fire. Track down the cause as soon as possible!

As far as the furnace goes: The fans are typically noisy but a grinding sound could mean the fan has dirt or debris in the blades or bad bearings.

Hope this helps.

John

ajelinek · 06-25-2012, 07:57 AM

Sorry, by auxiliary I actually meant Direct current. We rarely use the generator but I'll try that tonight and see if the same buzz exists.

For the furnace, the noise isn't in the furnace itself, it's in the electrical box. When the furnace kicks in, the fan in the electrical box comes on and that's what's making the sound. I guess we'll just open up the box and see what's going on. My service guy is ordering a new fan just in case - can't get it in until 2 days before a 2 week trip!

We'll get into the box tonight and see what we can find. Thanks for the suggestions!

SAABDOCTOR · 06-25-2012, 08:22 AM

Sounds like your on the right track wit the fan. just make sure your shore power is disconected. be fore you go pokin in there

good luck

patagoniadave · 02-01-2014, 08:25 AM

Quote:

Originally Posted by ajelinek

When we have any one of the lights turned on in our 3912LEV, the electrical panel has a terrible buzzing noise - it's not just a soft hum, it's very noticeable. We've had the camper now for a little over a year and it seems like it's getting worse. Happens both on battery OR auxilliary power. Can get it in for service in a week or so, but if it's a quick fix I can just do it myself.

There is also a terrible grinding noise in the electrical box when the furnace kicks on - seems like a bearing going out in the cooling fan in the box, but not sure. Any experiences in these areas?

Were you able to determine what it is? I stayed in my rig for the first time last night, and there was a loud noise coming out of the box all night whenever under load.

I was just about to come post a question, but decided to use the search function first. ;-)

Thank you

Festus2 · 02-01-2014, 08:33 AM

Whenever you turn the lights on or the converter is "working", you will hear the sound of the fan running. This is normal as the converter is simply "keeping itself cool" to prevent over-heating.
In our unit, the noise is more of a hum than anything - not loud or annoying. It's there but in the background and; after a while, hardly noticeable.

As mentioned above, turn off the power BEFORE you go poking around the converter. If you are not familiar with electrical circuits perhaps you should leave this to someone who knows what they are doing.

patagoniadave · 02-01-2014, 10:11 AM

Quote:

Originally Posted by Festus2

Whenever you turn the lights on or the converter is "working", you will hear the sound of the fan running. This is normal as the converter is simply "keeping itself cool" to prevent over-heating.
In our unit, the noise is more of a hum than anything - not loud or annoying. It's there but in the background and; after a while, hardly noticeable.

As mentioned above, turn off the power BEFORE you go poking around the converter. If you are not familiar with electrical circuits perhaps you should leave this to someone who knows what they are doing.

The noise was incredibly loud last night, I could hear it through the closed doors. Strangely, I shut down all of the power this morning, including the fridge, then powered back on. The loud noise stopped, and reverted to the muted hum, even when I cranked it all back on. I pulled the panel cover off to verify, and it is coming from the fan on the converter. I am going to blow it out with compressed air like I would for the computer, and if the loud noise comes back, I may see if I can replace the fan?

Thanks to all

**hankpage** · 02-01-2014, 11:08 AM

Quote:

Originally Posted by patagoniadave

The noise was incredibly loud last night, I could hear it through the closed doors. Strangely, I shut down all of the power this morning, including the fridge, then powered back on. The loud noise stopped, and reverted to the muted hum, even when I cranked it all back on. I pulled the panel cover off to verify, and it is coming from the fan on the converter. I am going to blow it out with compressed air like I would for the computer, and if the loud noise comes back, I may see if I can replace the fan?

Thanks to all

On an '04 trailer that dust is what I would suspect first but if any doubt replace the fan so the converter does not overheat. As mentioned be sure to disconnect shore power.

patagoniadave · 02-01-2014, 12:20 PM

Quote:

Originally Posted by hankpage

On an '04 trailer that dust is what I would suspect first but if any doubt replace the fan so the converter does not overheat. As mentioned be sure to disconnect shore power.

Yeah, blowing it out is about all I am willing to do on my own. I'll have an electrician come look at it, but it seems to have quieted down. Maybe the answer to my air condition problem is hidden in there as well.

Thank you

**JRTJH** · 02-01-2014, 07:06 PM

I'm not sure what type of converter you have in a 2004 RV. Back in the 90's, converters were pretty much nothing more than a big, heavy duty stepdown transformer with a bridge rectifier stuck on the output. Most of them weighed in excess of 30 lbs and when the transformer would get a workout, it would overheat and start buzzing. That's why most of them, back then, were installed in the front compartment of fifth wheels or in a back corner or underneath most travel trailers. Our Holiday Rambler had a Progressive Dynamics 60 amp converter mounted under the trailer in the "enclosed heated basement" which was the same as today's coroplast basement, but was covered with roll aluminum sheeting.

The converter started going out, we were a bazillion miles from home, it was night and we were watching TV. The converter, under the trailer was buzzing so loud that we couldn't hear the TV and it was louder than the non-ducted A/C which was right over our heads.

You might want to check the type of converter you have, the buzzing you hear may be the transformer starting to go out.

patagoniadave · 02-02-2014, 09:04 AM

Quote:

Originally Posted by JRTJH

You might want to check the type of converter you have, the buzzing you hear may be the transformer starting to go out.

The thing that the fan was making noise on is fairly small, located under my electrical panel. About the same size and shape as a car stereo amplifier. I am assuming this is the converter? If the heavy buzzing starts again I will pull off the panel and see if I can located the rough area of the sound.

**JRTJH** · 02-02-2014, 10:16 AM

Yes, that is your converter. If it's a "small thing behind the circuit breaker panel, it's not the old style I was talking about. The "old" Progressive Dynamics heavy units were at least the size of a 12pack of Bud Lite. What you have is the newer style, probably a WFCO. It still has a transformer with an added fan, so it's probably the fan blades dirty (think computer cooling fan) causing it to wobble.

patagoniadave · 02-03-2014, 06:06 PM

This is a totally spur of the moment, unresearched question, but are all outlets set to run through the converter, or are some only wired to shore power?

**JRTJH** · 02-03-2014, 06:54 PM

NONE of the outlets run through the converter. The converter's only purpose is to "convert" 120VAC to 12VDC. It provides "simulated" battery power when connected to shore power and charges the battery when 120VAC is available.

None of the circuit breakers or 12 volt fuses are "connected through" the converter. The circuit breakers are "connected" to the AC distribution panel and powered by the shore power cord. The 12 volt fuses are "connected through" the converter and they are the 12 volt distribution panel.

There is a circuit breaker to protect the converter, but neither that circuit breaker or any others "run through" the converter. Its sole function is 12 VDC and circuit breakers are 120VDC. They are two different "animals".

patagoniadave · 02-03-2014, 07:12 PM

Quote:

Originally Posted by JRTJH

NONE of the outlets run through the converter. The converter's only purpose is to "convert" 120VAC to 12VDC. It provides "simulated" battery power when connected to shore power and charges the battery when 120VAC is available.

None of the circuit breakers or 12 volt fuses are "connected through" the converter. The circuit breakers are "connected" to the AC distribution panel and powered by the shore power cord. The 12 volt fuses are "connected through" the converter and they are the 12 volt distribution panel.

There is a circuit breaker to protect the converter, but neither that circuit breaker or any others "run through" the converter. Its sole function is 12 VDC and circuit breakers are 120VDC. They are two different "animals".

Yes, I think Louie fixed me via pm, palm slap has been applied. I made a bad assumption the night that the converter was running so loudly, that since the only thing plugged in and running that night was an electric heater, that the outlet was somehow routed through the converter. I then realized that the fridge was running, and not hooked up to propane, and I think that it is routed through the converter? If not, I have no idea what was putting the load on the converter that night.

Thanks for putting up with my inane questions!

**JRTJH** · 02-03-2014, 07:32 PM

The "normal" load on the converter when it is plugged into shore power is the charger circuit in the converter (as much as 9 or 10 amps), the discrete loads like the CO detector, radio memory circuits, thermostat power, refrigerator control circuits, cabin lights. Depending on the battery condition, you could have a significant load on the converter. The refrigerator 12 volt power only controls the electronics. The reefer heater circuit is 120 volts and does not affect the converter load.

Other than lights you might have had on, the battery charger (in the converter) would have been the "big load" if the batteries had not been charged for a few days and you had run the slides in and out a couple of times and usedd the landing gear to hitch/disconnect the trailer from the tow vehicle.

patagoniadave · 02-03-2014, 07:36 PM

Quote:

Originally Posted by JRTJH

The "normal" load on the converter when it is plugged into shore power is the charger circuit in the converter (as much as 9 or 10 amps), the discrete loads like the CO detector, radio memory circuits, thermostat power, refrigerator control circuits, cabin lights. Depending on the battery condition, you could have a significant load on the converter. The refrigerator 12 volt power only controls the electronics. The reefer heater circuit is 120 volts and does not affect the converter load.

Other than lights you might have had on, the battery charger (in the converter) would have been the "big load" if the batteries had not been charged for a few days and you had run the slides in and out a couple of times and usedd the landing gear to hitch/disconnect the trailer from the tow vehicle.

Ok, I am going to go with battery charger then. We had been unplugged for a while waiting for the electrician to verify that the pole was wired properly, so it was probably pretty low. I do not think any lights were on, but maybe I left an exterior on.

abneynormal · 02-08-2014, 06:26 PM

the power converter in my 3912 started making a high pitched buzz to squeal before it went out. if you turn the outside spots on that sucker will scream and some times the lights would flash. its a wfco 75 amp I believe. note if it does go out you can still live in it with a battery charger hooked up temporarly. I know. be sure to put it on 2 amps.

You may also like: