How often do you turn your DC on and off

[John Ziebron]

Malcolm started a thread about an A/C energy monitor which got me to thinking about turning some equipment on and off, mainly the DC. All of our power equipment have motors which, if I recall correctly, have a high startup current. When I work in my shop, like most of you I presume, we try to plan as much of the work at one time at a particular machine like a jointer or table saw and leave them running.

Then I started to realize that I turn my dist collector on and off a fair amount, even if it's only going to be a minute or two before I have to turn it on again. It's a 3 HP cyclone and it sits on the other side of an insulated wall so the noise isn't too bad. But it's just a habit I got into years ago with a smaller DC.

I was wondering if anyone has done even a basic analysis to determine if the DC were going to be off for some minimal time would it be better energy use wise to just leave it on. I know places like millworks and cabinet shops leave their's on for the whole shift but what about us hobbyists. I'd like to hear what others do.

[Rick Potter]

I turn on my 3HP gorilla when I need it and turn it off when done. Sometimes it is only on for a few minutes. Even so, I doubt I have ever turned it on more than the recommended 6 times per hour.

The longest times are during long drum sanding sessions when it may be on an hour or maybe two at a time.

It's about 6 years old, and my only problems are the crummy remote receiver that came with it.

[Bill Orbine]

I have all my machines tied to one central dust collector with automatic gates. Any machine powered up starts the dust collector and there is a programmable shut down time for dust collector after machine is shut off. I set the 5hp collector to shut off 1 minute after last machine is turned off. 1 minute is usually more than enough time when I'm hopping from machine to machine. I did not set that time so much for energy savings but rather reduce the strain of starting and stopping the dust collector so often when I'm on a run of series of different cuts.

[John K Jordan]

There was a thread about this not long ago, not about the energy use but the health of the motor. Apparently turning DC on too often in a short period of time can cause a large motor to overheat. I don't remember the numbers or the sources of these warnings but you might try a forum search or maybe someone will remember the details.

I personally leave mine running if I will use it again in a few minutes. (5hp ClearVue cyclone) Mine is in a sound insulated closet so most of the noise in the shop is from the air rushing though tool intakes so I close the blast gates until needed. This, BTW, reduces energy use since the motor doesn't have to work so hard to spin the impeller in a partial vacuum/reduced pressure. (I used an amp meter on mine to verify this.)

JKJ


Malcolm started a thread about an A/C energy monitor which got me to thinking about turning some equipment on and off, mainly the DC. All of our power equipment have motors which, if I recall correctly, have a high startup current. When I work in my shop, like most of you I presume, we try to plan as much of the work at one time at a particular machine like a jointer or table saw and leave them running.

Then I started to realize that I turn my dist collector on and off a fair amount, even if it's only going to be a minute or two before I have to turn it on again. It's a 3 HP cyclone and it sits on the other side of an insulated wall so the noise isn't too bad. But it's just a habit I got into years ago with a smaller DC.

I was wondering if anyone has done even a basic analysis to determine if the DC were going to be off for some minimal time would it be better energy use wise to just leave it on. I know places like millworks and cabinet shops leave their's on for the whole shift but what about us hobbyists. I'd like to hear what others do.

[Mike Cutler]

John

There are lots of studies done on this and it becomes somewhat situational. In other words, what work is the motor performing?
A table saw just spinning isn't going to have near the amperage draw as once it starts cutting, which is the same with most of the other wood working machines in your shop. The dust collector is one of the exceptions. It is always under some type of load due to the dynamics of the system.
Starting and stopping motors isn't so much an energy saving strategy, though it does accomplish that, it is more to extend the life of a motor in a given application. The more starts and stops on a motor, the shorter the life of the motor will be, all things being equal. The start up current on a motor is much higher than while it is running, but that inrush current is only there for a few seconds.
I tend to leave my dust collector running until I know I'm done with it. I don't start and stop it with each machine. Rarely though is it on than more than a 1/2 and hour at a time. Generally this is the time I'm running material through the Jointer and the planer. I think the longest I remember it running continuously was 4-5 hours when I was cutting parts for an ultralight airplane wing. The band saw was running that whole time also. That was fun.

[John K Jordan]

...I think the longest I remember it running continuously was 4-5 hours when I was cutting parts for an ultralight airplane wing. The band saw was running that whole time also. That was fun.

Not on the topic, but do you have pictures of the ultralight wing (and plane) somewhere, perhaps in a thread here?

[Mike Cutler]

John
Sadly, no. Everything left my house as "parts". Kind of like a giant RC model kit.
I don't fly but a friend does/did? and was making his own ultralight. He had a cut list from the plans, and we started out with four, 22' long, sitka spruce beams, maybe 4"x8"? and started making the parts. It was pretty cool, we had to bring the band saw into the garage and run the boards through a side door and then out the front of the garage. I like doing stuff like this.

[Jim Becker]

I do not turn my cyclone on and off with any frequency and often keep it running as I move from tool to tool and just change blast gates. And with the CNC in the shop now, my cyclone runs almost all day some days with only a few times being shut down. That's using less energy this year with the MiniSpilt in my shop than just the resistance heater did one year prior without the CNC in play. And since my cyclone is in a sound reduced closet, keeping it running isn't really an issue with sound level. The music over-powers it quite nicely. :) :D

[Bill Dufour]

I believe compressor duty motors are designed for more starts per hour then standard motors. Of course most of them do not have a nameplate horsepower rating. So Sears can lie about how much horsepower you have.
Bil l.

[Lee Schierer]

My DC turns on automatically each time I start my TS. For other shop tools such as the planer, I have to manually move the plugh for the DC to a live outlet, set up the duct work and then start the planer.

As far as the efficiency question. The start up current is a very short duration spike so it shouldn't take very long for it running continuously to equal the start up surge. It is likely that running it for just a few seconds would use as much as the start up spike.

[Tom Bain]

I tend to leave mine running, unless I know I won’t be at/using a machine within the next 15 minutes. The DC also tends to help circulate the heat in the shop which is a nice two-fer when leaving it running.

[Mick Simon]

My DC is in the garage next to my shop, so ambient noise is pretty low. I tend to leave it running if I know I'll be doing any machine operations within a half hour or so. Otherwise I turn it off.

[Art Mann]

I tend to leave mine running if I am actively machining wood. Since I don't have an air filter, I figure it might help a little to clean the air in the shop.

[Bill Space]

My dust collector is connected to start when I manually open a blast gate.

I must move slower than most of you guys. I close the gate after doing what I need to do at that tool and the dust collector motor shuts down.

When I get to the next tool, and open the blast gate when I am about to start that tool, the dust collector starts again.

As a homeowner, power factor issues are no concern. My slow moves between each machine makes leaving the DC running a waste of energy.

Oh! To be young and fast again like you guys! Guys that can leave the dust collector running because you move so fast! :D

I would gladly leave my DC running all day if I could return to those days...

[Curt Harms]

My DC turns on automatically each time I start my TS. For other shop tools such as the planer, I have to manually move the plugh for the DC to a live outlet, set up the duct work and then start the planer.

As far as the efficiency question. The start up current is a very short duration spike so it shouldn't take very long for it running continuously to equal the start up surge. It is likely that running it for just a few seconds would use as much as the start up spike.

I think the biggest issue with frequent starts on induction motors is heat rather than electricity use. There's quite a bit of heat created in a short time on start and the motor doesn't run long enough and isn't off long enough for the heat to dissipate. Lower quality motors have lower quality insulation in the windings so they're more of an issue. At least that's my understanding.

[Martin Wasner]

As a homeowner, power factor issues are no concern.

Our main dust collector is a 20hp unit with a 36" impeller. You can hear the meter scream when it starts. Not really, but when you throw an amperage meter on it, it's pulling over 100 amps of 480 briefly.

There's four of us in the shop, the general rule is to take a quick poll by looking around and see if anyone else looks like they need it, or if they'll need it soon. There's no reason to shut it down if it's just going to be cranked up again I a few minutes. Some days it doesn't hardly get turned on, others it runs almost all day continuously.

The router has it's own 7.5hp cyclone. That kills me. There's no point in shutting it down between sheets, but it stinks leaving it on when unloading, cleaning the table and loading another sheet. It's doing what it needs to only half the time.

[Chris Parks]

Leaving it on and having blast gates open is useful for cleaning the air of the floating small micron sized dust particles. I installed a Cleavue in a Mens Shed and it runs all day and is never turned off, turning the machines on opens & closes the blast gates as needed. They have one blast gate open permanently I believe.

[Bruce Wrenn]

I have a sensor in the power panel that controls DC. Any outlet, whose leads pass the sensor, cuts DC on. After machine is turned off, DC runs for 10 seconds to clear pipes. At each location, I have two 110's and a single 220 outlets. The left 110 outlet. is connected thru sensor, along with the 220 outlet

[Ed Pollock]

I turn my 3hp Oneida on and off as needed. Sometimes that means more than 6 times in an hour but usually not. If I know I am jumping right into another cut, I will leave it on. I like to have the TV or Radio on in the shop so I tend to turn it off so that I can hear it between operations. Sometimes it will be on as little as a minute or two, sometimes it will be on for an hour.


If that leads to premature failure 10 years from now, instead of 15 years from now.... I guess I can live with that.

[Jim Kirkpatrick]

I've had a Grizzly G1029 2 hp (220v) dust collector since 1990. It's 28 years old. I turn it off and on as needed, I've never thought about the 6 times/ hr. rule. I turn it on and off sometimes just for 1 cut. It's seen thousands upon thousands of hours and still running strong. The only thing I've had to do maintenance-wise is tighten the impeller blades twice. Perhaps the smaller motor doesn't have the same heat issues as others have mentioned. I'm going to be upgrading to a 3hp cyclone presently so perhaps I'll have to think about this in the future.

[Frank Pratt]

The bigger the motor, the more important it is to observe the start/hr. specification. A 5 HP motor will be damaged more easily than a 1 HP motor.

[Terry Wawro]

OK, I'll fess up. I turn my dust collector on and off all the time. I have a remote in my shop apron so it makes it easy. My dust collector is not in a separate sound proof room. It makes a lot of noise so I don't leave it on any longer than I have to. Will it shorten the life? Probably.

[Rod Sheridan]

I tend to leave mine running if I am actively machining wood. Since I don't have an air filter, I figure it might help a little to clean the air in the shop.

This is what I do, I leave the cyclone running, unless it's more than 15 to 30 minutes between machine uses.

My cyclone uses 10 to 20 cents per hour in electricity depending upon the time of day, so energy costs aren't an issue, clean air is.

regards, Rod.

[Martin Wasner]

My cyclone uses 10 to 20 cents per hour in electricity depending upon the time of day, so energy costs aren't an issue, clean air is.


At four cents a minute, your attitude adjusts quickly.

[Rod Sheridan]

At four cents a minute, your attitude adjusts quickly.

That's true, however I have no revenue to offset the costs.

I understand you run a business Martin.

Where I work we spend about $1,500 per day on electricity, it's not an issue as we have the revenue to pay for it, obviously we monitor our energy usage however we wouldn't shut equipment off to start it up again in 15 minutes.

Most motors where I work are only shut off once per month for inspection and annual maintenance. The other equipment is only shut down for annual maintenance.......Rod.

[Bill Carey]

OK, I'll fess up. I turn my dust collector on and off all the time. I have a remote in my shop apron so it makes it easy. My dust collector is not in a separate sound proof room. It makes a lot of noise so I don't leave it on any longer than I have to. Will it shorten the life? Probably.

2nd to that . Remote on the apron and I need to move the hose from machine to machine. So on and off it goes.

[Ben Rivel]

3HP V-3000 here and once its up and running I only shut it off if I know Im not going to be making a cut for another 20-30 minutes or more. I try to plan all my cuts before the dust collector even comes on to minimize switching it on and off. Hasnt been an issue so far and noise isnt a problem for me as my hearing protection has bluetooth connected speakers in them so I just keep jammin right though it all :)

[Russell Yokley]

I turn mine on and work from station to station leaving it on. If there is ever a choice to turn it off for a minute for setup at another station I tend to choose leave it on. It helps that my Motor/cyclone are in a hall outside of my shop but inside my basement.