Cycling your DC frequently

[ChrisA Edwards]

I've got a Jet 1.5HP 110v DC, that has been converted to two stage with an Oneida Super Dust Deputy XL and a 55 gallon drum beneath. All my ducting is 5" metal HVAC pipe, which are currently fed by 4" manual blast gates.

This has been working great for the past 5 years for my hobbyist use.

The only weak area is where the shavings drop out of the cyclone into the drum. If I'm planing 8"+ wide boards, 8'+ long, the 4" flex hose has no problem keeping up with the tool, (A3-31) but puts so many shavings, at the exit drop of the cyclone, that it occasionally clogs.

I usually have to walk over and shake my debris drum a little to clear this clog, not a huge deal and it's rare that I'm doing a lot of these size of boards.

For other operations, where I'm making sawdust rather than volumes of shavings, it works great.

My DC is triggered via an iVac switch, so cycles on an off as I use a power tool. This means I can sometimes cycle in 30+ times and hour.

I have 230V available, so if I was to replace this system with say a CV1800 or similar, can those units handle the cycling that my current system seems to handle with ease? If I were to update, I would most likely change all my existing ducting to 6".

Thanks.

[glenn bradley]

My 2HP Grizzly G0440 gets cycled frequently. Nothing like 30 times an hour but, several times an hour during milling operations. I've been doing this for about 12 years.

[Andrew More]

I've got a Grizzly G0443, cycle it several times per hour, no issues yet. I've only had it a year or two. I believe at one point Oneida was issuing some warnings about doing this, but somebody looked into it, and they were thinking more at the factory level, with 40 hour work weeks, over the course of several years, rather than the usual weekend warrior stuff.

[Frank Pratt]

Speaking generally, the bigger the motor, the fewer cycles/hour it can tolerate. But even at just 1 1/2 HP, 30/hour is probably more than is good for it. A 5 HP motor would not last long doing that. Something like a table saw motor will fare much better because the load has much less inertia. My 3 HP table saw comes up to speed very quickly, much less than a second, but the 5 HP blower takes a few seconds. It's the long start time that cooks a motor.

[George Yetka]

i have the cv1800 and have no issue with 5-6 times an hour manually. Mines on the factory remote so i never bothered with ivac and all my small hand tool stuff is on a festool vac with dust deputy.
The problem with alot of cycling would be if the motor didnt wind down before restarting. If you did move to a bigger unit I would recommend a small vac for handheld power tools.Cheaper to run/ faster to power up/quieter/if your venting outside you dont have to empty all your heat for a minute of sanding

I had the super dust deputy xl on my HF 2hp with the same joiner and would frequently have to remove the lid of the can and reach my arm up in to let the dust free. Didnt enjoy that but it beet climbing in the attic to empty bag.

[John K Jordan]

I use the 5hp ClearVue. I was told to try to cycle no more than 6 times an hour with a motor that size. I tend to leave the DC on and shut the blast gate when moving between tools or if I’m going to use it again in a little while. The motor pulls less current and runs cooler when the blast gates are closed.


i have the cv1800 and have no issue with 5-6 times an hour manually. Mines on the factory remote so i never bothered with ivac and all my small hand tool stuff is on a festool vac with dust deputy.
The problem with alot of cycling would be if the motor didnt wind down before restarting. If you did move to a bigger unit I would recommend a small vac for handheld power tools.Cheaper to run/ faster to power up/quieter/if your venting outside you dont have to empty all your heat for a minute of sanding

I had the super dust deputy xl on my HF 2hp with the same joiner and would frequently have to remove the lid of the can and reach my arm up in to let the dust free. Didnt enjoy that but it beet climbing in the attic to empty bag.

[ChrisA Edwards]

The motor pulls less current and runs cooler when the blast gates are closed.

That seems counter intuitive. When you cover the end of a vacuum hose, you hear the motor load up normally. I guess you need a certain amount of resistance to stop the motor spinning up too fast.


For my small tools, I use a Festool vacuum.

When I said 30 cycles an hour, that's probably excessive and the max that would happen, although turning my saw on and off, on average, every 2 minutes, doesn't seem over excessive. I guess when I'm in that mode, I'd just leave the DC running, something I do now when ripping a board and then jointing that freshly ripped edge. I just don't want to update and find myself restricted.

Also George, as you have the CV1800, how did you find the noise difference between you old HF and the CV1800? My Jet isn't super loud right now, but I could totally re-arrange my ducting runs to where I could put a Cv1800 in a somewhat sound proof closet.

[Malcolm McLeod]

That seems counter intuitive. When you cover the end of a vacuum hose, you hear the motor load up normally. ....

What you hear is the motor unloading. The air flow across the fan stalls and since the motor is accelerating much less air mass, there is less work > less current > less heat > etc..

[ChrisA Edwards]

What you hear is the motor unloading. The air flow across the fan stalls and since the motor is accelerating much less air mass, there is less work > less current > less heat > etc..
Thanks, that makes sense.

[Frank Pratt]

The problem with alot of cycling would be if the motor didnt wind down before restarting.

Actually, if you're just going to be starting it up right away, it's better to do so before it runs down to a stop. Waiting for it to stop just means the start phase will be that much longer.

[Ken Parris]

Chris as you have said it makes sense and John and Malcolm are both correct. I managed an engineering department for several years. We manufactured industrial plants that had dust collectors (baghouses) that had exhaust fans with radial blades up to 72" diameter. The big ones required twin 300 hp motors. They pulled so much power coming up to speed that we started the first up in steps and when it came up to speed started the second one. This dimmed the lights in nearby homes. We put the plants in running stops sometimes, but didn't want to stop the fans because of having to repeat the starting again. So we closed the dampers, the hp dropped, and the amperage dropped. Also when starting up the fans the dampers were closed to reduce the starting load. You would help your dust collector motor a little if you started it with the gates closed, although probably not enough to worry about it.

[Bill Dufour]

10-12 starts per hour is a good rule of thumb for longer motor life. Many air compressors are continuous run for this reason.
Bil lD

[John K Jordan]

10-12 starts per hour is a good rule of thumb for longer motor life. Many air compressors are continuous run for this reason.
Bil lD

Are you referring to all motors? I thought the recommendations depended on the motor, hp, load, and application.

[Justin Rapp]

Is there a way to bypass that switch so you can leave the DC running if you are doing a lot of continues work that requires cycling of the woodworking tool? I know their is 'noise pollution' but that i what earplugs are for.

[ChrisA Edwards]

Is there a way to bypass that switch so you can leave the DC running if you are doing a lot of continues work that requires cycling of the woodworking tool? I know their is 'noise pollution' but that i what earplugs are for.

Yes, I can either start up my DC using the auto switch, DC powers on as the tool starts and powers off about 10 seconds after the tool power is turned off, or set the DC to manual on/off and, as you suggest, and leave it running while I complete several cuts or other operations that may require some tool adjustment.

So yes, I could work around the limitation of not having the DC run quite so sporadically.

[Bill Dufour]

Are you referring to all motors? I thought the recommendations depended on the motor, hp, load, and application.


I am referring to general use ac motors under 3hp or so with moderate starting loads.
Bill D

[John K Jordan]

Are you referring to all motors? I thought the recommendations depended on the motor, hp, load, and application.


I am referring to general use ac motors under 3hp or so with moderate starting loads.
Bill D


That makes sense. Both my DC and air compressor are 5hp. I've monitored the startup currents and they were significant.

I think the advice to start a large cyclone with all blast gates closed is good. I didn't think of that. The compressor has an unloader for startup.

JKJ

[David L Morse]

That makes sense. Both my DC and air compressor are 5hp. I've monitored the startup currents and they were significant.

I think the advice to start a large cyclone with all blast gates closed is good. I didn't think of that. The compressor has an unloader for startup.

JKJ

The inertia of the impeller has the largest impact on the total energy required for starting. Until I actually tested it I didn't think that closing gates would have much effect. Last December I got a new ammeter that let me look at current draw over time and one of the first things I played with was my DC.

https://sawmillcreek.org/attachment.php?attachmentid=428088&d=1584372906

That's the equivalent of 67A for 2.8s with no airflow and 67A for 3.3s at maximum flow. That's about 18% more heating of the motor for each start cycle comparing maximum to zero flow.

[Malcolm McLeod]

Yes, I can either start up my DC using the auto switch, DC powers on as the tool starts and powers off about 10 seconds after the tool power is turned off, or set the DC to manual on/off and, as you suggest, and leave it running while I complete several cuts or other operations that may require some tool adjustment.

So yes, I could work around the limitation of not having the DC run quite so sporadically.

The 10 sec delay you reference is called an "off-delay timer", and in the iVac / iGauge family of products - to my knowledge - is a fixed interval, just to clear ducts. It would be a fairly simple matter to supplement this time with an adjustable off-delay timer (Grainger, Allied Electronics, etc :: $20-$40-ish). The output signal from your existing interface device would drive the input of the new timer, then use the timer output to drive your DC run signal. You could then set the timer to slightly longer than setup times, say 5-minutes, allowing machine change-overs to be done with the DC still running. The DC would still shut-off for any extended idle time - - say for a nap:).

[Charles P. Wright]

iVac has a MRT (minimum run-time) switch suitable for larger DCs. Typically combined with their contactor (though you can use anyone's contactor, they have everything in a convenient box). For my Oneida V-3000 I have connected the contactor to my system with a 3 minute delay. I could go for 10 minutes to meet the manual's 6 times per hour recommendation. If I have a few more starts/stops than 6 occasionally I won't get worried for my hobby use. This setting covers the table saw starting/stopping quickly not having the system start for just a minute at a time.

[Malcolm McLeod]

... in the iVac / iGauge family of products - to my knowledge - is a fixed interval, ...


iVac has a MRT (minimum run-time) switch suitable for larger DCs. Typically combined with their contactor (though you can use anyone's contactor, they have everything in a convenient box). For my Oneida V-3000 I have connected the contactor to my system with a 3 minute delay. I could go for 10 minutes to meet the manual's 6 times per hour recommendation. If I have a few more starts/stops than 6 occasionally I won't get worried for my hobby use. This setting covers the table saw starting/stopping quickly not having the system start for just a minute at a time.

My bad. I was thinking of the i-Socket. So, adding the additional timer module to the iVac may be frivolous. Unnecessary too.:(

[Tom Stenzel]

The inertia of the impeller has the largest impact on the total energy required for starting. Until I actually tested it I didn't think that closing gates would have much effect. Last December I got a new ammeter that let me look at current draw over time and one of the first things I played with was my DC.

https://sawmillcreek.org/attachment.php?attachmentid=428088&d=1584372906

That's the equivalent of 67A for 2.8s with no airflow and 67A for 3.3s at maximum flow. That's about 18% more heating of the motor for each start cycle comparing maximum to zero flow.

Dave you nailed it.

At work we had the scrubber fans were a bit bigger as they ran on 4160 VAC. But the same principles applied as the fan start was interlocked with the inlet damper being closed. If the damper was open meant there was no start. Also only two successive starts were allowed. After that it couldn't be started for some time period enforced by the motor controls. I forget how long but it seemed an hour or more.

The motor's cooling fan isn't moving an appreciable amount of air until it spins up. If the motor is soon stopped the heat in the windings from the inrush current won't dissipate. Subsequent starts can overheat the windings. The rotor will get hot too but it can take a whole lot more abuse than the windings. The store of heat in the rotor helps keep the windings hot longer than you would expect. It's best to keep it running or limit the number of starts.

-Tom

[Mark Bolton]

If your cycling your DC that often why not just leave it running? Your saving zero on electric with the repeated starts and your losing your shirt on motor wear and tear.

Starting and stopping a table saw is no comparison to spinning up a heavy impeller especially if you leave any gates open and its moving air on start.

Ive know a couple guys to put all their tooling on DC start switches and in a day when they are going to the miter saw 100 times they will smell the typical roached motor smell in their shop.

There are days I without a doubt crowd the oneida 6x/hr cycle time on two 5HP cyclones in the shop but for the most part when they are fired up and the shop is working (even if Im alone) they are just left on. Same with table saw. If I have a ton of cutting to do even walking half way across the shop to check fits the table saw just stays running. Motor, electricity, cycling switchgear and contactors, not worth it to beat the heck out of the tool 100 times a day as opposed to 5.

As youve already understood.. when you hear your shop vac or dust collector whip up (high pitch) when you block the hose, close a gate, thats not the motor under load, its the motor under no load. No different than if you were pulling a heavy load up a hill in your truck and shove the clutch in.... the motor would whip up free wheeling under no load. Opening the entrance pipe to your DC wide open will give you the lowest sound because its moving the most air it can and working the hardest.

Dump the on/off switches and just let it run.

[Frank Pratt]

This thread has brought out the fact that auto start/stop systems for dust collection are ill conceived & just not a good idea. If you want to go high tech & automatic with the DC, a system the automatically opens & closes blast gates while not controlling the blower is far better.

[Mark Bolton]

This thread has brought out the fact that auto start/stop systems for dust collection are ill conceived & just not a good idea.

I think too many people get hemmed up in the "cool factor". I could never imagine cycling up any DC even a shop vac 40-50 times a day. If Im sanding, the vac stays running. I wouldnt mind an auto-off time delay feature (talked about in the thread) but even that would be useless because I know when Im done sanding a job? And I shut the vac off? To have the vac shut off 3 seconds after I set the sander down to grab the next part? Yeek.

[Jeff Clode]

This was an excellent and very informative thread...thanks to all who contributed
Jeff

[Travis Conner]

I didn't know it was harmfull to the motor. I just thought frequent startups meant you go through more capacitors? Lots of things startup and turn off frequently. I mean air compressors, table saws it's not really safe to leave them running. I've left the bandsaw on a few times cause I knew I was going to come back a minute later.

[John K Jordan]

Are you referring to all motors? I thought the recommendations depended on the motor, hp, load, and application.


I didn't know it was harmfull to the motor. I just thought frequent startups meant you go through more capacitors? Lots of things startup and turn off frequently. I mean air compressors, table saws it's not really safe to leave them running. I've left the bandsaw on a few times cause I knew I was going to come back a minute later.

If I'm processing green wood into turning blanks for a couple of hours I leave both the bandsaw and the cyclone on the entire time, sometimes just closing the blast gate until needed.

JKJ

[Mark Bolton]

I mean air compressors, table saws it's not really safe to leave them running. I've left the bandsaw on a few times cause I knew I was going to come back a minute later.

Personal preference but Im not sure what the safety issue is if your TS is running for 5 hours straight while your standing there shoving parts through or its sitting there idling while your walking away checking fits? Im not talking about leaving a saw whipping for an hour and half while you go have lunch or talk of the phone. Im talking about making a cut, walking to the bench, check the fit, walk back, cut again, and so on. Or breaking down sheets and stacking parts on a cart, moving them across he shop, get another sheet, wash rinse repeat. Stopping and starting the saw for that is a waste of electricity (miniscule), wear, and time, in my opinion and is no more dangerous, moreso less, than it running with an operator. Bandsaw may be debatable in a busy shop in that its pretty easy to no see a traveling band blade but would still not be a problem in most cases for me.

The motor issue is the difference between whipping up a 10 or 12 inch saw blade and a 24" diameter heavy cast DC impeller. Hobby shop, or small full time shop like mine are far different than a large plant but the principle is the same which is why in large plants you see large motors just idling.

[ChrisA Edwards]

So after starting this thread, I followed the advice here from many of the excellent posts.

Earlier last week, I planed about 400 bd/ft of 6/4 rough sawn on the two flat side down to 29mm. I crept up on the final thickness, making about 4 passes through the planer slowly removing the rough sawn marks and imperfections from each side.

I also put a straight edge on each board using another home made jig and my table saw. https://www.youtube.com/watch?v=zlypo69JsdA

For this process I had the A3-31 and my DC running constantly for about two hours, bluetooth headphones with some music of choice was a must. Yes the picture says November, I've been procrastinating.

https://i1094.photobucket.com/albums/i452/cedwards874/Woodworking/Shutters/FirstWoodPickup_zps3eu5y4re.jpg

This week it was time to start making the Shutter frames, both inner and outer and the picture below is about 100 pieces that make up those. This was about 6 hours elapsed over a couple of days.

https://i1094.photobucket.com/albums/i452/cedwards874/Woodworking/Shutters/ShutterFramesCut2_zpsyfbjupvy.jpg

(There's a pile of scrap off cuts in the center, the good stuff is all labeled and stacked)

So trying to minimize starts of the 4 tools that would be used, Sawstop Tablesaw, Hammer A3-31 JP, Dewalt DW780 Miter saw and my Jet DC, I batched stuff up in piles for each process.

First was to cut all the boards to approximate final length on the miter saw, most were in the 2000mm length. The DC was running constantly for this connected to my home made miter saw dust collection box.https://www.youtube.com/watch?v=Fh1QVE_yHf4

Next up was dimensioning the wood to width. This was a process of using my JP, in jointing mode, and the tablesaw. For this, the DC was also on constantly and likewise the J/P was running all the time. The saw was powered off when I needed to make a 'close to the blade' fence adjustment.

Worked great, but now I'm seriously thinking about a cabinet or sound baffle around the DC. It's not super loud, but gets annoying after long periods, even with headphones on.

This pile of wood will hopefully look like these in the not so distant future.
https://i1094.photobucket.com/albums/i452/cedwards874/Woodworking/Shutters/MasterBedroonFinished_zps72zksgpd.jpg

[Mark Bolton]

Thats a beautiful stack of material in the truck... I am always impressed by vendors with nice packs like that. Even better looking end result. Nicely done.