Exhaust (dust collector) overheating

[sarah beck]

About a month ago I got this King Canada 3/4 HP dust collector to use as my laser exhaust. http://www.kingcanada.com/Products.htm?CD=19&ID=12000 It is a lot more powerful (and unfortunately also way noisier) than the one that came with my system. I built a little doghouse for it outside and there is about a 6 foot run of 4" flex hose between the laser and the wall vent that the doghouse is attached to. The dust collector is attached to the other side of that vent. It worked really well, no fumes inside at all, but just in the last week it has started overheating after running for about 1/2 an hour. I didn't put any filters on it anywhere, so I am wondering if that is what is causing it to overheat...too much dust in there? I did try giving it a good blast of air with my compressor hose, into the vents on the dust collector but I didn't open up the motor or switch housing as it is hard to get at and I'll basically have to take apart the doghouse to get in there. I should have done a hinged roof...didn't think of that until now! I suppose it could also be not enough ventilation into the doghouse, but it is a cool day today and it wasn't a problem for the first few weeks that I used it, which is why I am wondering about dust. The blast of air didn't work because it just overheated again.

I have read a lot of the exhaust threads in this forum, but I couldn't find much about installing a filter that wasn't a big charcoal filtration system to remove fumes before venting. I live in a rural area with no neighbours, so I am not as concerned about the fumes going outside. (Although I know I shouldn't be venting "badness" out into the environment and I'll probably install a filtration system for that eventually!)
So, does it sound like it is dust in the motor that is causing the overheating? Should I put a filter in? And, if so, any suggestions on where I should put it within the system and what kind of filter? How do I install it?

Thanks!! Hopefully one day I'll be in the position to answer questions, but for now I'm still on the asking end.

[David Somers]

Sarah,

I don't have that brand of dust collector blower. I use one I got from Lowes ages ago, and I use it on my big wood lathe. Lots of dust through it and more all the time and for hours at a time. No issues.

Is it possible you have an obstruction elsewhere in the hose between the blower and the laser? Focus on anywhere there is a joint first. Something might have caught in the joint and blocked it there. Then if nothing presents itself check the rest of the line.

[Gary Hair]

I have had my $95.00 Harbor Freight setup for almost 8 years and it runs for 10 hours some days and at least 4-5 every day - never been cleaned and works like a charm. That said, I'll probably have to buy a new one in the next few days since I just tempted the universe... Blockage usually isn't a problem for dust collectors as the less air flow the less you tax the motor. Check this out by opening and closing a blast gate and you'll find the motor runs faster when the gate is completely closed - completely counter-intuitive, but true. I'm betting you have a bad motor, bearing, or fan, or something wrong with it besides a bit of dust - especially since it's only a month old.

[sarah beck]

Ok, I have an email into the company..we'll see what they suggest. I googled "dust collectors overheating" and came up with "dust in the motor" as a possible solution. I did just check in the hose, but there isn't anything there. It doesn't really suck up the bits that fall out when I'm cutting anyway, so I don't think there is anything large stuck anywhere. Thanks for your answers... I wish we had a Harbour Freight up here in Canada.

[Kev Williams]

The problem is lack of ventilation. The motor uses ambient air for cooling, not the pumped air. In your case the ambient air is what's in the box. Some of the air will vent out, much of it will continue to get warmer since the motor is heating it up. It will work okay for awhile, but the blower is going to leak dust into the box, where it's trapped with nowhere to go but thru the motor's vents. The crud builds up on the motor, and the air vents slowly grow smaller, until there's not enough air flow to cool the motor.

I'll bet a buck that's your problem...

[sarah beck]

That does sound like it could be the problem. I guess I should take the motor housing off and give it a good cleaning before I give up on this machine. I'll also try increasing the ventilation in the box. Thanks for that reply, it does make a lot of sense. I wish I didn't have to put it outside, (and therefore inside the doghouse where ventilation becomes an issue) but it is SO LOUD I couldn't stand having it in my work area. It is still really loud even on the other side of the wall, but it helps a bit. I think it would need to be half way to Newfoundland before the sound got any less bothersome!

Sure Kev, I can afford a dollar...:)

[Robert Walters]

You could cut an opening or two in the doghouse and install a couple of these:
http://www.homedepot.com/p/Construction-Metals-Inc-6-in-x-14-in-Steel-Foundation-Vent-TW146/202092771

or

http://www.homedepot.com/p/Speedi-Products-6-in-White-Round-Soffit-Vent-SM-RSV-6/202907302
(These might be better at keeping rain out)


One low to let in fresh air, and one high to exhaust heat.
Maybe on opposite sides of the doghouse to get a cross flow going.

It'll be a little louder, but better than burning out the motor.

[John Bion]

Hi Sarah,
As others have said, ventilation for the motor is important. You don't say what you've been cutting; many woods and especially MDF clog up a fans inlet mesh cover and also the internal fins etc, these require occasional stripping and cleaning off, sometimes with some floor polish stripper and a pressure washer (obviously with the electrics well away). Definitely improve ventilation so that the fans cooling mechanism can blow cool, clean air over itself.
Kind regards,
John

[sarah beck]

Thanks again for the suggestions. I think I have come up with a solution to the ventilation problem. My shop is up on concrete footings and there's about 5 feet of vertical space under the building beneath the floor where the laser is. I put the fan underneath the building where it won't get rained on, instead of having it in the doghouse. I can't believe I didn't think of it sooner! When I installed the doghouse I was just thinking about minimising the distance between the laser and the dust collector.

I did a test cut to see if there was still enough suction from the dust collector, because there is an extra five feet of duct and two more bends in the pipe with this new setup, but it seems fine, no fumes. Hopefully this will work, but I guess I may still need to clean out the dust that has gotten into the motor. I'll see if it still overheats with the new setup before I take it apart. I'm not sure quite how to clean it, but I guess it will be apparent when I take the motor housing off? And guess what? It is much quieter. So, hopefully problem solved!