Share DC Idea, 1st Post

[Jim Volk]

Ok ok, deep breath. 1st post jitters. I thought I might start this out by sharing an idea about dust collection. Cannot take credit for this idea. That belongs to LOML's uncle. I thought it was quite an ingenious idea. One of those potential bad events with dust collections units would be burning up the motor by overloading it. This I suppose can come from many ways but if we were to run our units very long without a blast gate. Poof! Not something I would look forward to. Well, this reduces if not eliminates that problem. It's a safety vent built into the duck work. It amounts to a little bit of 1/4" Lexan, some aluminum flat stock, a couple of hinges, treaded rod and 2 light springs. You can adjust the tension on the springs so the lexan flaps open up only when all the gates are closed. I don't have much time with it yet but it seems to work. I have not checked the motor load but wifes uncle did on his and he claims it works. That was enough for me. So, there you go. Whats everyone think?

[Ken Fitzgerald]

Jim.....I could be wrong but......I was under the impression that with all the gates closed...there is no air movement and therefore the motor is drawing the least amount of load current. If, however, all the gates are open, the most amount of air is moving and the motor is drawing the most amount of current....?

I'll find out ...I have a clamp on amp meter and I've just about got my DC installed.

[Jim O'Dell]

Jim, welcome to the Creek. Sorry, but I have to agree with Ken. I've checked it on mine. Most amps are drawn with all gates open. The motor is doing the most work then. It is backward to the normal thinking, that's why I tested it myself to prove others right or wrong.
Now I have heard of this type of device being used to increase the flow when say a 4" hose is being used that ties in to a 6" horizontal main run to keep the FPM up in the horizontal run so the debris doesn't fall out of the air stream in the pipe because of lack of air movement. That would have some merit. Your version looks very nice, and I'd like to see some more views and or drawings on how it is constructed. THANKS! Jim.

[Jim Volk]

Huh? wouldn't you know it. My first test drive at a post and I'm all wet with my idea. That can make one a little red in the face! I really don't have any drawings. There all in my head. Probably a good place for them. If your interested though, I'll try to get some better pictures, but basically I cut a circle that fit roughly close to the ID of the T. Then I split it into 3 pieces by cutting a strip out of the middle. Attached hinges to both sides and attached the threaded rod to the center of the strip. Bent some aluminum around the outside of the T and attached it there. I think you get the idea.

[Jason Morgan]

I thought that what Jm Volk was saying was the problem. If you run the impeller with no load, say in a sealed box, then it can overload the motor. In essence, the motor needs some load to function properly. If you get to a point where the motor has NO load (turning in dead air say) then you can get into a runaway situation. The max load would be when all the blast gates are open, but that would be when it would draw and work at its max. A good motor should run at it's running current draw for a long time.

I'm not exactly sure why, but I think Jim Volk is right.
EDIT: Nope...did some research...those guys are right. Min current draw is at no load condition...max current draw is at max load ie no ductwork or all gates open.

[Norman Pyles]

I don't know either way, but welcome to the creek, Jim.:)

[Ken Fitzgerald]

Jim,

I didn't mean to offend you. I had the same line of thought as you but someone posted that it wasn't that way. I've got a clamp on ammeter. Though not from Missouri, I 'm going to find out for myself in the next couple of weeks. I have one more run of 6" pipe to run and I'll have mine completely installed.

[Jim Volk]

Ken,

No offense taken. I'm actually glad to get the feedback. If it doen't work in the way I thought then I'd like to know.

[Jason Beam]

Jim,

I didn't mean to offend you. I had the same line of thought as you but someone posted that it wasn't that way. I've got a clamp on ammeter. Though not from Missouri, I 'm going to find out for myself in the next couple of weeks. I have one more run of 6" pipe to run and I'll have mine completely installed.


Yup, that's the right thought, Ken. Now if it's a squirrel cage, that may work differently, but these centrifugal impellers don't have any problem being trapped completely. They like it, in fact. Hardly draw any current.

As for your clamp-on ammeter - I'm sure you know this already (i sure didn't!), but they don't work at all just hookin' em around the cord of the machine. Turns out you gotta clamp it around ONE of them or they cancel each other out and keep readin' 0! :eek: Or so the instruction manual says. I have yet to get mine to work :rolleyes:

[Ken Fitzgerald]

Jason,

I have this brand new clamp on ammeter attachment for my multi-meter. I was really concerned about offending Jim.....I have 2 of the 3 duct circuits installed.....so I thought...I"ll just run out there and find out what the current is with 1 effective blast gate open and then I'll open the other two. I can comfirm you can't just wrap it around the cord going to the motor:o! The it dawned on me....out of phase......no magnetic resultant field..........Saturday I'll pull the cover off the box and get around a wire.:o

[Jim Dunn]

As for your clamp-on ammeter - I'm sure you know this already (i sure didn't!), but they don't work at all just hookin' em around the cord of the machine. Turns out you gotta clamp it around ONE of them or they cancel each other out and keep readin' 0! :eek: Or so the instruction manual says. I have yet to get mine to work :rolleyes:

That is right. You have to hook it around just one lead of the motor or you won't get any reading at all.

I don't have an answer as to the ampere draw of a motor under no load as relates to dust collection equipment. I do know that impeller type pumps must work under a load or they draw to many amp's.

[Don Abele]

Ken, for my clamp-on I made up an extension cord 12" long that I carefully stripped the outer jacket off of and separated the individual lines. This way I can clamp around only one line for testing. I have one for 240 and one for 120. Cost about $20 to make them and took like 15 minutes. When I test 240 motors, I do test both hots, just to make sure there is no difference.

Be well,

Doc