Controlling the Hidden Beast

[McRabbet]

There has been considerable attention by woodworkers here and on other forums concerning Dust Collection. I recently purchased a ClearVue Cyclone (like at least five others here) and I've looked at how others have installed their units and the duct works to rid their shops from all that dangerous dust we produce. In my case, I'll be installing my 8-foot tall beast in a higher crawl space under my 800 SF shop and running 6" PVC ductwork under the floor like Alan in Little Washington. Alan and I share the challenge of controlling our cyclones from a floor away and need to know when the sawdust bin is full to avoid filling expensive filters with more than a trickle of very fine dust. Alan conceived and documented his bin sensor last year in two threads (this links to the second one and it has a link to the first). Mine is not much different, but uses some different components. Here is a schematic diagram, which I'll explain below the graphic.



Here's how it works. 230V power is fed to the 5 HP Leeson motor on the ClearVue through a Fasco H230B 2-pole contactor (common lead not shown), which is Normally Open (NO) in the Off position. 110V power is fed through a remote switch and through the Normally Closed (NC) contacts of a small "ice cube" relay (so named because of its shape and size). When the Remote transmitter closes the remote switch, power is sent to the 110V coil on the Contactor and the Blower Motor starts up and runs as long as coil is energized. OK so far or are you ?? Over to the right side of the diagram, you'll see Alan's small light and photo eye (about $13 at Lowe's) that are placed in the bottom end of the cyclone, just above the bin. When the light beam is blocked by sawdust and chip accumulation -- i.e., the bin is full -- the Red line is energized and it activates the coil in the Ice Cube relay, opening the NC contacts and sending the 110V power to an indicator bulb in my shop space above. And, because the 230V Contactor no longer is energized, 230V power does not get to the Blower Motor and it shuts down!! The switch by the candelabra is used when emptying the bin -- this keeps the photo eye dark and it keeps the blower from restarting prematurely (if I forget to toggle the remote control transmitter off, that is!)

I'm currently in discussions with Jim Murphy (Fernhollowman) and Alan Schaffter (Alan in Little Washington) about improvements in our control circuits beyond this design -- We are looking at options to have a Momentary Contact Switch at each power tool to turn the DC On or Off and delay timers to protect the big motors from overheating due to excessive On/Off cycles (spinning up a big impeller pulls heavy amperage and heat is generated and retained if done too often).

I've built a mock-up and will post pictures when I can -- I have shoulder surgery this next week and so I'm doing arm-chair work these days and for several weeks to come....

By the way -- this will work on about any dust collector with a bin -- you may need a brighter lamp for a big bag unit, but it is ideal for any cyclone. I can provide links for any of the parts for this -- aside from the remote switch which was about $25 at Ames Hardware, the other parts are less than $50, including a good enclosure.

[toolferone]

Okay, I really need to build this soon. My cyclone is in a closet off the back of my closet. I have over filled it several times. I will need to mount my eye down on the bin as I have about 4' of pipe from the bottom of the cyclone to the bin and I don't want the pipe filling up with sawdust before the eye catches it. Do you see any problems with that?

[Jim Murphy]

Originally Posted by McRabbet

By the way -- this will work on about any dust collector with a bin -- you may need a brighter lamp for a big bag unit, but it is ideal for any cyclone. I can provide links for any of the parts for this -- aside from the remote switch which was about $25 at Ames Hardware, the other parts are less than $50, including a good enclosure.

Rob,

As we progress, I suggest that since you have started giving part numbers, we make this easier for others by specifying the terminal connections the various relays need. I had to mind-meld with AlanILW to begin to understand the wiring diagram for the delay relay. It would be much easier for others if we said you can buy a SuperDuper Model XYZ delay relay from InternetElectronics (with url provided) for about $28 plus shipping. You then wire a 120v black lead to terminal 1, jumper it to terminal 2, and connect switch Z to terminals 5 and 6. That sort of thing. OR, on the schematic, provide terminal numbers at each component. OR, both.

After all, we're all here to help, right?

[McRabbet]

The only issue I can think of is false triggering from a heavy slug of sawdust if you are using a floor sweep. If your pipe up from the bin to the base of the cyclone was clear (even if is is clear flex duct), then you could see if there is a clear spiral of dust traveleing down to the bin as there is on a ClearVue. That way, you could place the sensor/light across a segment that remains "clearer" during normal use. Another option is to use a larger/brighter bulb, but I'll warn you that 20W - 40W - 60W chandelier candelabra bulbs don't last very long and they generate lots of heat -- and do not operate them any way except base down (doesn't apply to the 7W ones). Hope this helps.

[McRabbet]

OK -- here's a parts list for key components of my schematic and then the wiring details:

1) Allen Bradley 700-HA32A1 Relay: Try http://tinyurl.com/3y6yjd $5-11 + shipping
2) Allen Bradley 700-HN125 Base Socket:http://tinyurl.com/2qj9ro $3.89 + shipping
3) Fasco H230B 2-pole contactor: http://tinyurl.com/2gk4bm $10.18 plus shipping
4) Carlon HW2190 Remote Control: http://tinyurl.com/yu3o3e $24.99 + Tax (Cary Ace Hdwe)
5) Universal Photoeye CP688: http://tinyurl.com/373w5p $12.93 at Home Depot or Lowes (Item 70551 = $12.96) + tax
6) Candelabra Socket: http://tinyurl.com/2dqmwc $2.98 at Lowes (in drawers near fuses).
7) Control Enclosure: http://tinyurl.com/2fh7zg $11.18 at Lowes.

I've also bought Handy boxes for the bin sensor and candelabra, light socket for the shop light and miscellaneous bushings, wire nuts, lug connectors etc. I bought a 6-foot Green outdoor rated light duty power cord and cut off the receptacle end (preserving the male plug) to connect the remote control to the Controls Enclosure.

Drill 10-32 clearance holes in the controls enclosure to mount the H230B and Allen-Bradley Base socket inside the bottom of the enclosure. Drill appropriate holes for 1/2" Romex bushings in left, right and lower sides opposite connections on the two components to feed 5 wires into the enclosure. Then make connections on the Controls parts as numbered:

H230B: Step 1: #10 Romex Black and White wires with Yellow (#10) female spade disconnects slide onto male spade connectors on Contactor end -- repeat on opposite side for 230V line to blower motor. Use wire nut to connect bare common wire (keeping it clear of other connectors). Step 2: Run a single Black #14 wire (I stripped some out of #14 Romex) from pin 4 of the base socket to either coil connector on H230B. Step 3: Run a White #14 wire from pin 5 of Base Socket to the other coil connector of H230B.

700-HA32A1/Base Socket: Step 1: Run the cut end of the Green cord that plugs into the Remote outlet through a bushing into the Controls Enclosure (left side) after stripping 4" of jacket and 1/2" of jacket on the 3 wires. Step 2: Connect White wire to Pin 8 and Black wire to pin 1 of the Base Socket (I used open end screw connectors crimped to the wires). Step 3: Run a piece of #14 Romex wire from shop Indicator light through bushing on opposite side of enclosure, strip as above and connect Black wire to pin 3 and White wire to pin 6. Step 4: Run a piece of 3-wire #14 Romex from box with photoeye at cyclone to controls enclosure, strip each end as above and cut off the Black wire. Feed remainder through bushing and connect Red wire to pin 2 and White wire to pin 7. Step 5: Connect the ground wires in this paragraph together with a wire nut.

I used a second small extension cord to feed the 7-watt candelabra, again cutting off the receptacle end. Black or hot side connects through a bushing in the handy box to a small toggle switch (in the cover plate)and other side of switch is connected to the candelabra base Black lead. The same incoming Hot or Black lead from the power cord is also connected to the Black side of a #14 Romex line run to the photoeye handy box. White leads of incoming power line and candelabra are connected together to White Romex wire with a wire nut. At the photoeye handy box, the three White leads (photoeye, and two Romex wires) are wired-nutted together, Black from Candelabra wire connects to photoeye Black and Red from Photoeye connects to the Red wire in the #14 3-wire Romex going to Controls Enclosure (remember to cut off the black lead in this wire). And be sure to connect the ground wires to the handy boxes and to incoming ground wires.

That's it. Questions??

[Alan in Little Washington]

Somehow I missed this thread. Since the original thread got a little geeky and long, I have been corresponding with Jim and Rob via e-mail. They have done a great job with photo documentation, identifying parts, and drawing schematics.

One minor change to Rob's schematic I suggested is to put a (the) safety switch between the black are red sensor wires, bypassing the sensor. This will keep the Allen Bradley 700 relay energized and and ensure the blower won't turn on when emptying the dust bin. The switch adjacent to the candelabra light will turn off the light, but it might be possible for stray ambient light to (de)activate the sensor and allow the blower to run if the main switch/remote is inadvertently left on.

As you may know, my DC system does not use a remote- I figured that I would put it down and not be able to find it like scores of missing pencils or the occasional tool, but I can start my system from one of many button locations and turn it off from that or any other location. There are a number of methods to achieve this. In addition to my method you can use relatively inexpensive (pulse sequencing) relay that will allow you to fully control your DC from any location using only one momentary SPST push button at each location. One push of any button will turn the system on, while the next push of any button will turn the system off. When I get around to it I will post these schematics and parts lists.

I am also working on an inexpensive homebuilt electro-pneumatic automatic blast gate and will post pictures when I achieve a reliable version.

[Alan in Little Washington]

Originally Posted by McRabbet

The only issue I can think of is false triggering from a heavy slug of sawdust if you are using a floor sweep. If your pipe up from the bin to the base of the cyclone was clear (even if is is clear flex duct), then you could see if there is a clear spiral of dust traveleing down to the bin as there is on a ClearVue. That way, you could place the sensor/light across a segment that remains "clearer" during normal use. Another option is to use a larger/brighter bulb, but I'll warn you that 20W - 40W - 60W chandelier candelabra bulbs don't last very long and they generate lots of heat -- and do not operate them any way except base down (doesn't apply to the 7W ones). Hope this helps.

After a year using my dust sensor, I have had maybe two false shutdowns using a 7W bulb- once when vacuuming up a pile of MDF dust, the other when a bulb burned out. The dust is just moving too fast and is spread out no longer in a "slug". Also, the cyclonic flow actually continues down into the dust bin and keeps the sensor clean. A future upgrade might be if a suitable LED can be found to replace the candelabra light.

[Alan in Little Washington]

Originally Posted by toolferone

Okay, I really need to build this soon. My cyclone is in a closet off the back of my closet. I have over filled it several times. I will need to mount my eye down on the bin as I have about 4' of pipe from the bottom of the cyclone to the bin and I don't want the pipe filling up with sawdust before the eye catches it. Do you see any problems with that?

Tom- sorry I am slow posting to this, but the sensor should really be mounted just above the bin where the cyclonic air flow will keep it clean. I believe previous attempts at optical dust sensors failed because they tried to put the sensor in the bin and/or did not use a supplemental light source. The dust is carrying a lot of static charge and will stick to and obscure the sensor and bulb, long before the bin is full.

Filling up the tube a little is no problem if there is a few inches of duct extending into the bin. In operation the dust will fill the bin until it reaches the duct extension, then, unlike water, will fill the extension only. The extension gives you free space at the top of the bin where the dust in the duct can drain. This also makes it easier to carry and empty the bin. Here is the sketch of this concept from my thread from last year.

[junquecol]

Alan, why not use a SSAC current sensor in the panel box to control the DC. When a machine turns on, DC comes on. By adding a delay on off timer, DC can be made to run after machine shut down. This allows for clearing the pipes. You only need to run one leg of a 220 circuit through the sensor. It can handle about (6) #12 wires through the coil. A sensor that is controlled by the blast gates opening/ closing, means that the gates will have to be operated before and after each cut. The only remote in my shop is for the hanging air cleaner.

[McRabbet]

Bruce, I considered using current sensor circuitry for mine as well -- there was a very good version published in Woodwork magazine a year or so ago. I've found that I try to leave my DC on (since it is under my shop, the noise is not troublesome) so that as I move from process to process, I only need to adjust a blast gate here or there. I keep my remote control transmitter pinned to my shop apron on an old Orvis "zinger", so it is always handy. If I do need to shut it down, I can at any time. I'm also concerned with motor overheating in cases where the blower has been cycled on and off too frequently and it hasn't had time to cool off a bit. Lets face it, a 15" impeller made of 3/16" steel has some weight that the motor has to spin up quickly and that generate heat.

I have revised my Controls Circuit schematic incorporating a suggestion that Alan made -- I added a toggle switch near the photo eye to insure that the relay coil remains energized when I'm emptying the bin after an automatic shut off. If the remote was left closed and light gets to the photo eye, it would re-start prematurely. This version also shows the pin connections on the small control relay. I've made a mock-up of the circuitry on a piece of plywood and it all works fine.

[junquecol]

I think this over heating from frequent starts thing is a crock. Any respectable manufacturer will design his fan / motor assembly for cycling. Think about how many times a saw, or air compressor starts per hour. In over five years of operation, my Cincinnatti Fan unit hasn't complained one bit. If it did over heat, the thermal over load would shut it down.

[ptt49er]

Originally Posted by Alan in Little Washington

A future upgrade might be if a suitable LED can be found to replace the candelabra light.

You're LED idea has my brain working...

You could use one of your old cell phone chargers that puts out a steady 12V DC to power a cluster of small LED's.

It wouldn't be too difficult to wire them up....

ANOTHER project for me to try, I'll let ya know how it goes

[Jim Murphy]

Originally Posted by junquecol

I think this over heating from frequent starts thing is a crock. Any respectable manufacturer will design his fan / motor assembly for cycling. Think about how many times a saw, or air compressor starts per hour. In over five years of operation, my Cincinnatti Fan unit hasn't complained one bit. If it did over heat, the thermal over load would shut it down.

Go here: http://www.ralphpill.com/calculators.shtml

Scroll down midway and find a table based on NEMA std. 10-MG which allow calculation of the MAX starts/hour for larger motors. Both NEMA and the individual motor mfrs. provide a MAX starts per hour. The 5HP Leeson in the CV system is rated at 6 starts per hour. As installed, the only motor I cannot access and remove singlehandedly is the DC motor. Why tempt fate?

[PurpleThumb]

Good Luck on the Pyranees neccessitated surgery if I don't talk to you before. I'm through the "pain" to the "sore "part of mine.
Thanks for the diagram and the sharing of info by you, Alan, and so many others. This truly is a GREAT site.

[Joe Scharle]

I trust that when you guys get this design finalized that you'll put in into a download area. When I finally get around to setting a DC up, I'll probably not be able to find this thread.
Good work & thx,
Joe