Working Van question....

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LocoKen

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Well, I'm not sure if I am putting this in the right place, but I don't know what section would be the right one. We should have an off-topic section in the forums for those "not quite sure" questions.

Anyway, here's my dilemma. A brand new conduit box was installed on my van and the rest of the fleet. There just isn't enough room inside the van to carry 10' lengths of conduit, so I talked my boss into getting them. Well, going down the road at about 45-60 mph we get a very loud hum. Has anyone figured out how to cut down on the noise or get rid of it completely? Sorry this is so generic of a question, but I figured since there are plenty of you out there that are in the industry, someone has got to have had this happen to them. Thanks in advance even if you don't have the answer to my problem. :)
 
I never get the hum from the conduit carrier, I get it from ladders.... And if that hum is generated the same way, heres the solution - roll up your window. :cool:

Anyway, I too had a wierd hum, but on my ladders, and it took a bit to find it. I'll tell you how I did, and maybe it will help you. It drove me crazy for a little while, then one day I was driving home and noticed the hum was gone... I reached up to see if the extention ladder was still there, or if I had forgotten to put it on the truck - it was there... But earlier in the day I had put a rag on the top of the runners so I wouldn't mar up the wall where I working. So as I am going down the freeway, I reeached up and pulled one off - and the hum came back a little. I pulled over for gas and coffee, and pulled the other one off, and the hum was back at full force. Then while driving again I tried something, I just knudged the ladder over a little so it wasn't quite perpindicular to the wind - the hum was gone.

I think it has something to do with turbulance across the squared edges of the ladder. You may be getting something simular with the conduit box. (My conduit carrier is 6" PVC pipe.) So anyway, I suggest you strap discarded stuffed animales to the conduit carrier until you figure out where the hum is coming from. When you do - epoxy that one in place.:rolleyes:
 
The hum from the ladder comes from the holes where the rungs penetrate the rails on an extension ladder.

To stop the hum, plug the first holes top and bottom in the front.

I don't know about the conduit box though.
Is it the diamond plate type or the open top type?
 
e57 said:
So as I am going down the freeway, I reeached up and pulled one off - and the hum came back a little. I pulled over for gas and coffee, and pulled the other one off...
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Yeah, right. LOL

You sure they didn't blow off as you were driving, Litterbug? :D

Just kidding. :)

I'd start with rubber inner-tubes on the rails, and see what that did.

Edit to add: Tim! That is one awesome avatar! :cool:
 
You guys are too funny! Well, as it seems, it may be the rack that was installed before the conduit box was installed that is making the noise. I can't be for sure, but I was talking to another electrician today, and he said he thought it was the rack making the noise as his did the same thing. (By the way, mine is the diamond plated rectangular box, not the round PVC one, or the openfaced one like you see on plumbers vans. Anyway, I'm going to try the "super-gluing" the stuffed animal to the parts idea and see if that works. If anything, I'll get some weird looks from the people passing by. LOL! Thanks for the serious and not-so-serious replies. Much appreciated!
 
stickboy1375 said:
Sorry to really get off topic, but how do you keep animated avatars animated? I can never get them to work?
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If the file size is bigger than 58k, then I think the forum software just uses the first image of the loop for the avatar.
 
I haven't done it, but I know a lot of guys who plug the holes in the ladder with expandable foam to stop the hum.

I just turn up the radio.
 
bradleyelectric said:
I get a hum so loud from my new van since I put the ladder rack on it the radio doesn't help. There are no ladders up there at the moment and it is the same.
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I've had the same problem. It's actually a very loud high pitched hum, once I get above 50 mph or so. I've solved the problem though, and you're not gonna believe how because it contradicts everything everyone else is saying. I keep a ladder up there now, all the time. Extension ladder, step ladder, it doesn't matter. No plugging holes or stuffing rags. The hum is gone and I can hear the radio again.
 
So how did you do it? Is it better than stuffed animals to create turbulance? Fins, spoilers?

Has anyone ever seen the rocket nose cone and fins on a conduit carrier?
 
The ladders are what generate the noise on mine.... The extention ladder specificaly, but if it is slightly asque - noise gone. (Same if Bugs and Daffy are stuck to it. ;) Without them I would surely lose my mind.) No problems with 8-12' A-frames.
 
I do believe you have a problem with harmonics. You need to change the strucal frame of the box, possibly a piece of all thread through the middle, or wedge soething in the box. Not in the way of conduit of course. Another idea may be a foam pad under the box, something on top of the box exerting downward pressure. Basicallly what you are trying to achieve is changing the length of the tuning fork, of course this could result in a worse hum. Expierment.
 
Mine was the ladder rack making the noise. AmericanVan sold me a spoiler that mounts under the first "rung" of a three rung rack. I have the AL powder coat white square tube, three section rack with the diamond plate box conduit carrier.
 
A buddy of mine had that same issue. I just got off the phone with him, asking how he solved it. His conduit carrier was bolted on the ladder racks, as I guess your's is. He unbolted the front and yanked it over a couple of inches and bolted it back down, effectively angling the whole box on the ladder racks a bit. The box is a little bit crooked now, but the hum is gone.
 
Jps1006 said:
Mine was the ladder rack making the noise. AmericanVan sold me a spoiler that mounts under the first "rung" of a three rung rack. I have the AL powder coat white square tube, three section rack with the diamond plate box conduit carrier.
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Exactly what I did and the noise is gone.
 
I moved the front rack up to where it is supposed to be (employees, someone had the front leg of the 3 section rack halfway between where it was supposed to be and the middle rack) and put an 8' up there. The noise is not as much, but still there. I'll throw an extention up there maybe tomorrow. I just noticed yesterday morning that there is already 3 dings in the top rear quarter of the passenger side. Noone knows how they got there. I don't think I'll ever buy another new van for employee use. This van was wrecked twice by 2 different technicians in low speed accidents before it had 7k miles on it. First a guy ran in the back of someone in stop and go traffic causing $2300. in damages to the front of the truck, than another guy backed into someone in a parking lot destoying the rear bumper.
 
Well, I did some experimenting with ladders and such and found that by putting an extension ladder on the opposite side of the rack took away "ALL" of the humming noise. And I have to tell you, I didn't notice it right away. We were traveling down the road to the second job of the day when I turned to my partner and said, "Hey, do you hear that?" He said, "What, I don't hear anything." I said, "Exactly! The hum is gone, and we didn't even realize it!" We were so used to hearing the hum that when it was gone, it caught us by surprise. Anyway, I'm not letting the Extension Ladder out of my sight now!
 
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