How frequently do you start/stop your cyclone?

[Glen Blanchard]

I am unsure if this belongs here or in the 'Workshops' forum, but I'll post it here. Moderators - move this thread if you wish.

After I installed my Oneida (3 h.p.) cyclone, I was pursuing the manual and read that it should not be turned on too frequently - that it is better to just leave it running. I am just a hobbyist and had never given a second thought to starting or stopping my previous (non-cyclone) dust collectors. I would prefer to turn the unit off after I have completed a cut or some cuts, unless I will be moving to another machine immediately. However, this might mean that I turn it back on in 5 minutes or so. This could theoretically go on and on. Do I need to be concerned about affecting the life of the motor (I assume that is the reason for Oneida's recommendation)? For those with a cyclone, do you give any thought to turning it off and restarting or do you start it up and let it run until you know you will give it a long term break?

[Mike Schuch]

I go threw this all the time with my rotary phase converter. A motor draws many times its rated run current when starting. When is it more efficient to just leave the motor running? I have never worried about motor life though... not with a decent quality motor and home shop usage patterns.

[Cody Colston]

[QUOTE=Glen Blanchard;1628551]I am unsure if this belongs here or in the 'Workshops' forum, but I'll post it here. Moderators - move this thread if you wish.[QUOTE]

Oh, you can be sure they will. :D

I have an Oneida cyclone and while I try to limit the on/off cycles as much as practical, I certainly don't obsess over it. I think the recommendation is to try to keep the cycles below six per hour.

One of these days, I intend to build an addition to the shop primarily to house the cyclone and the air compressor. When I do, I'll probably let the cyclone run longer. With it inside the main shop and unenclosed, I can't tolerate the noise when it isn't needed for dust collection. I subconsciously tend to rush, too, when the cyclone is running.

[Jim Becker]

Glen, I try to avoid turning my Oneida cyclone on and off with great frequency, but don't feel guilty if I need to do that once in awhile. Most of the time, I'm working on an operation when it's just as convenient to leave it running...and it's in a closet, so noise isn't an issue, even less so if all the gates are closed.

[Kent Chasson]

Good timing for the question as I've been trying to understand this too. So far, my understanding is as follows and I would love to get a better understanding if this is incorrect.

It seems that DCs need a lot of torque to get that big impeller up to speed, a lot more torque than something like a 10" tablesaw blade. The start capacitor stores and delivers extra power to the motor to provide that torque and that capacitor disengages when the motor is mostly up to speed. The capacitor gets pretty hot during this process and multiple starts in quick succession may start to melt things. The question of how many starts in what period of time is the big question. The good news is that it's a capacitor problem (as in $15-$20) and not a $350 motor problem. Again, that is researched opinion, not fact.

[Bruce Wrenn]

Because my cyclone is controlled by a current sensor in the panel box, it cuts of and on each time a power tool on one of the tool circuits starts. I don't quite understand Onedia's reasoning, as all other power tools start and stop more than 6 times per hour. But the submersible pumps I install recommend no more than 6 start stop cycles per hour. Remember these motors are under water. How often does your air compressor start per hour?

[Dave MacArthur]

It could also have something to do with NEC motor ratings? When they engineer the machine, perhaps they base the extension cord and plugs and recommended wiring size etc. on it's use criteria. For example:
How much you have to over-engineer the ampacity of the wiring to a motor is based on it's "use" classification, there is continuous, periodic, and intermittent. I'm not sure of the start/stop cycle per hour criteria, but you have to look up the duty-cycle descriptions in table 430.22(E). You'd THINK that a motor rated for continuous duty like the Baldor, that you ran at something less than that like 15-30 minutes then off, you'd be able to use the normally calculate wire, or even less, but it's the exact opposite of what you'd think! You're not even allowed to engineer a continuous duty motor circuit wiring for "periodic" according to the NEC table above, it doesn't give the motor time to cool down from the current inrush of starting! So, for continuous duty motors run less than continuous, it's basically a 1.4 correction factor to NAMEPLATE current, not FLA.
So, for a 5HP baldor, depending on how you classify it's use:
continuous duty = 125% * 28A = 35A
intermittant or periodic duty = 140% * 19.5A = 27.3A
varying duty = 200% * 19.5A = 38A

Anyhoo, you can see that a company publishing a set number of maximum cycles/hour on/off may possibly come from meeting NEC motor circuit classifications they engineered to. All motors possible to run continuous must be calculated as such, but...it gets complicated, and I can see this being a factor in cord design etc.

[John Coloccia]

The explanation of what the starter caps do isn't quite right, but that's the reason. You beat up on the starter caps. My Clearvue starts up in just a few seconds. Others take longer. The longer a motor takes to get up to speed, the more it beats up on the caps.

If I'm running a bunch of power tool steps, I just leave it running. I already have my ear plugs and face-shield on, so I just move from machine to machine and do what I need to do. I try to bunch up my power tool use so it happens all at once. That has nothing to do with my cyclone...that's just how I like to work since the power tools are mostly used for stock preparation.

[Alan Bienlein]

I turn my cyclone on and I'll leave run atleast ten minutes even if I only make a quick cut. This works for me because I've found that if I turn it off right away I'm always needing to trim the piece I just cut or do another operation on another machine plus in the winter it helps to heat the shop.

[David Giles]

When was the last time that someone complained about motor failure on a dust collector or cyclone? While infrequent motor cycling is good practice to extend motor life, it is not a real problem in the real world. I turn my DC on (and off) whenever I feel like it. If it would only break, I'd get a better one! No luck so far.

[glenn bradley]

I do not conciously leave my machine on or really pay attention. I do tend to turn it on, use the tblesaw for the planned cuts, turn it off. Turn it on, run my material through the planer, turn it off and so forth. Grizzly G0440, been doing this a couple of years, no issues.

[Jim O'Dell]

The Leeson motor my Clear Vue uses also had that warning. I do try to keep the on/offs to 4 or 5 per hour just in case. I'd leave it on, but it might be 30 minutes or more as I prep for the next cut(s). But it is funny you don't see the same warning for say table saw motors. Should be the same issue, though the start up issues aren't as great due to lower mass in the machine to get going. But what about compressors? Lots of stress there getting up to speed. I'm not going to lose sleep over the need to start and stop my CV. Jim.

[John Coloccia]

It has to do with the time, Jim. All the cap is doing is retarding the phase to one of the coils. If it didn't do this, there would be practically no net torque on the motor. Retarding the phase causes enough imbalance to get the motor going. Once the motor is up to speed, that cap switches out (the click you hear). Larger motors swinging large bits of metal take much longer to start up, and hence heat up the starter cap much more. Table saw motors spin up very quickly, putting practically no heat on the caps at all. Larger bandsaws excel at killing their caps because they tend to go on and off a lot, plus they take forever to spool up do to the heavy wheels.

[Rod Sheridan]

I guess it could have to do with poor quality starting capacitors, however the issue is generally one of winding and rotor bar heating.

A dust collector runs at full load continuously, unlike a table saw which runs at maybe 25% capacity maximum on a an averaged basis.

During accelleration the motor windings, and the rotor bars which are cast aluminum, are subjected to much higher heating inputs.

If the motor is cool (table saw motor with very little load) the motor can easilly dissipate this heat.

If the motor is at rated temperature, it can only accept so much additional heat before it's damaged, so you have a number of hot starts per hour permitted.

Note that your table saw motor also has this restriction, however you never run into it because the motor isn't hot.

Regards, Rod.

[Jim Eller]

See #13 in this tread, right from the Gorilla's mouth:
http://www.sawmillcreek.org/showthread.php?124443-how-long-do-you-run-your-dust-collector&highlight=

It may answer your question.

Jim

[mreza Salav]

I wonder how much in electricity you will be paying more over the long run in order to save the motor by keeping the motor
running instead of turning it off; depending on the use the cost might be a lot more than the cost of a new motor if you just use it
ignoring this suggestion and buying a new motor when (and if) it fails.

[Curt Harms]

I wonder how much in electricity you will be paying more over the long run in order to save the motor by keeping the motor
running instead of turning it off; depending on the use the cost might be a lot more than the cost of a new motor if you just use it
ignoring this suggestion and buying a new motor when (and if) it fails.

That is a consideration. A way to minimize power usage (and noise) is to keep all the blast gates closed. An electric motor doing less work-moving less air-uses less electricity.

[Larry Edgerton]

The noise drives me nuts. I shut mine off with a remote in my pocket as soon as the machine is turned off. Been over ten years, no problems, worn out three remotes though.....

[Sean Nagle]

The noise drives me nuts. I shut mine off with a remote in my pocket as soon as the machine is turned off. Been over ten years, no problems, worn out three remotes though.....

Don't people wear hearing protection? I wear earmuffs whenever using most any power tool in the shop. Exceptions are drill press, lathe and drill/driver.

[Scott T Smith]

I have an automatic transfer switch in my shop, which has several guages for amps, voltage, cycles, etc. It is very insightful to watch the amp guages when starting equipment.

Without question, of all of the single phase equipment in my shop the Oneida 3 hp Super Dust Gorilla pulled the second longest load - about 3 seconds of 40A + current during startup; after that it dropped down to a few amps.

The 30 hp rotary phase converter pulls the most current, but still only about 1 second - not as long as the Oneida.

All of the rest of my equipment tweaks the meter for less than on second.

This could have something to do with it.

[Leo Graywacz]

I guess it could have to do with poor quality starting capacitors, however the issue is generally one of winding and rotor bar heating.

A dust collector runs at full load continuously, unlike a table saw which runs at maybe 25% capacity maximum on a an averaged basis.

During accelleration the motor windings, and the rotor bars which are cast aluminum, are subjected to much higher heating inputs.

If the motor is cool (table saw motor with very little load) the motor can easilly dissipate this heat.

If the motor is at rated temperature, it can only accept so much additional heat before it's damaged, so you have a number of hot starts per hour permitted.

Note that your table saw motor also has this restriction, however you never run into it because the motor isn't hot.

Regards, Rod.

This is exactly correct.:cool:

[glenn bradley]

Just for grins I kept track today (I'm off work). I spent about 7 hours in the shop and powered on/off the Cyclone 19 times and the bagger 3 times. Doesn't really mean anything but, I was curious.

[Larry Edgerton]

Don't people wear hearing protection? I wear earmuffs whenever using most any power tool in the shop. Exceptions are drill press, lathe and drill/driver.

Congradulations!

I don't think his question has anything to do with ear protection, could be wrong....

[Sean Nagle]

Congradulations!

Apparently hearing loss can adversely affect spelling as well :)

[Phil Thien]

For a little bit of extra safety margin (if you're power cycling a lot), you could make sure all your blast gates are closed when powering-up. This will make it easier/faster for the motor to spin the blower up.

[Dick Thomas]

To expand a bit on Rod's comments, the amonut of heat generated during startup depends heavily upon the load the motor carries during startup: Your tablesaw has very little load, since it's simply rotating the blade, not (hopefully) trying to take a full depth cut in oak. On the other hand, unless you have closed all air inlets/blast gates/dampers, etc., the blower in your DC or cyclone is open to pull full air capacity, i.e., full working load, as it comes up to speed. This put the blower motor under much more stress than the saw motor, requiring less frequent start cycles.

As an extreme example of this effect, years ago I ran a plant where we used a large spray dryer. The main blower was either 200 or 250HP/2300VAC. Capacity 30,000cfm @ 30+ " H2O: To start the blower, we had to completely close all air dampers, let it come up to speed under zero airflow, then slowly open dampers to load. It ran all week after starting.

[Ole Anderson]

After reading the recommendation from Oneida to limit the DC to 6 starts per hour, I went the extra mile and sound insulated the closet, now I am at only 70 dBa at 10 feet so letting it run while I think about and set up my next operation is more tolerable and ear protection isn't needed, except for my noisey machines.

[Kevin L. Pauba]

Phil, the idea of closing all blast gates during start up is interesting. I wonder if it would be worthwhile to add a "master gate" on the inlet to the cyclone (possibly operated automatically) that would be closed on start-up and reopened when the blower is up to speed?

[David Hostetler]

FWIW, I generally don't get more than about 2 hours / day to spend in the shop. When I am able to get in there, I start the DC prior to working with any connectable tools. I will leave it running as long as I am cutting, shaping, sanding /etc... I swap hose from bench top tool to bench top tool, so any loose sawdust or junk on the tool gets sucked up by the running DC during the switching phase...

I have been known to stop the DC, take measurements, do more layout work etc... then restart the DC... That is mostly to reduce the noise getting into the house... I need to get my wiring done in the shop so that I can keep the shop door fully closed (for now I am pulling power for the DC via heavy gauge extension cord into the laundry room, off of the dedicated washing machine circuit... what a pain!)

[Rick Moyer]

Phil, the idea of closing all blast gates during start up is interesting. I wonder if it would be worthwhile to add a "master gate" on the inlet to the cyclone (possibly operated automatically) that would be closed on start-up and reopened when the blower is up to speed?

I usually turn mine on/off when I turn on/off a given tool I'm using, so sometimes frequently, sometimes not so much if I'm not jumping from machine to machine (in which case I'd let it on then anyway). I usually have my blast gates closed, open the one for the tool I'll be using, and THEN turn on the DC. It sounds like I could turn on the DC BEFORE opening the corresponding blast gate. Would this be better?

[Phil Thien]

I usually turn mine on/off when I turn on/off a given tool I'm using, so sometimes frequently, sometimes not so much if I'm not jumping from machine to machine (in which case I'd let it on then anyway). I usually have my blast gates closed, open the one for the tool I'll be using, and THEN turn on the DC. It sounds like I could turn on the DC BEFORE opening the corresponding blast gate. Would this be better?

It will theoretically put less of a load on the motor.

And I suppose someone could make a master gate that automatically opened after the DC was up to speed. Don't know if it would be worthwhile, as it is just as easy to start the DC and then lean over and open the gate.

Someone should measure how much current their cyclone pulls at startup with a 4" gate open vs. a 6" gate open vs. no gates open.

[Ole Anderson]

Someone should measure how much current their cyclone pulls at startup with a 4" gate open vs. a 6" gate open vs. no gates open.

Yes it would be interesting to see the results. I suspect one of the reasons for the high start load on the DC is just trying to spin up the mass of the heavy fan wheel. Ever notice how long it takes to come to a stop?

[Phil Thien]

Yes it would be interesting to see the results. I suspect one of the reasons for the high start load on the DC is just trying to spin up the mass of the heavy fan wheel. Ever notice how long it takes to come to a stop?

I suspect you're correct.

[greg wood]

Someone else alluded to this. Has anyone actually had an issue or know of anyone who has?
In a production environment where you were turning it on and off say a dozen times an hour, hour after hour, 8 - 16 hours a day, 5 or 6 days a week, etc., I could see how this might be an issue. But my question would be for most of us, if we did exceed the 6 times an hour say 5 times a year, is there really a need for concern?

[Aaron Rowland]

The don't stop/start your motor thing started a long time ago due to problems with the Asia made motors burning out. Early motors were terrible ,loose winding and not even dipped after winding. They also used Class A insulation which is the lowest temp wire insulation used. Any over temp and good bye motor.

That's pretty well fixed now. The quality of Taiwan stuff is amazing compared to only 5 years ago. I think they are sweating the China made stuff. China is doing to them what Taiwan did to our manufacturing. Competition is good for us!

The other thing is some suppliers use under sized motors so as to cut price. That poor motor works so hard it over heats and it's to small to get rid of excess heat. I have a Euro made big band saw. Huge cast iron wheels. Little tiny 2 HP motor for what should of been a 3 HP. The motor blew out about 2 weeks ago and a Italy replacement is $700.00. Not a happy camper here. I am working on using an American Baldor 3HP. End of problem. The failure in this case was not frequent on/off but being undersized. RIP.

So can you turn a motor on/off many times an hour? Yet and no. If its a junker or under sized NO. If It's an American Baldor or Leeson of the right size YES with a slight modification.

How do you know if it's the right size? If it comes up to speed in 1-2 seconds max your OK. Any longer then that and it's undersized. Working way to hard. Aluminum impellers take a huge start load off the motor. Only Penn State and Oneida use Aluminum. They cost more. Uh, maybe. They also allow a smaller motor to be used and right back to over load if not careful. A cost cutting cheat so watch out. Clear Vue uses steel impellers but a huge 5 HP motor and American made. Up to speed fast.

Starting with the gates open or close makes no difference. At low speed before the starting cap drops out there is no air load open or closed. Takes a while for air to start flowing and building pressure. So it's the impeller inertia that's causes the load and slow stop.

The Mod I mentioned is placing a resistor across the start capacitor. That bleeds off the charge and prevents the contact points from arcing during rapid cycling. That creates a lot of grief to the Cap and motor. Grainier sells the resistor kit for about $12 with 10 resistors Part # 2Mew1 or 2mew2.. Good deal if you have 10 motors. Not so good if you have only one motor. The resistor is a 15K, 2Watt, bought most anywhere for $1-2. I use a 240V industrial light bulb instead of the resistor. My motors are out side and the bulb tells me whats going on. They are lit when the motor is running, act as a brake when turned turned off, and bleeds the resistor down when the motor relay kicks in during cost down. Fun to watch as it cycles though the various cycles. For longer life of the bulb I use a diode in one leg. Never replace a bulb since I made that change. I bang the beast on /off at will with Auto gates . As a hobby guy working on one piece at a time I may turn the cyclone on/off 20 times or more an hour. Zero problems with caps or motor over a very long time.

[Leo Graywacz]

Steel impellers are not fire code rated, they can spark and start a fire.

[Aaron Rowland]

Steel impellers are not fire code rated, they can spark and start a fire.

I'm not a bit up to date on Pro shops. For hobby use or pro wth less then 5 employees the rules used to be different. I know of no fires or explosions in hobby duct work including the infamous PVC static electric. That has been 100% debunked for a long period of time. The claim is made" well maybe it could happen." True and Hxxx might freeze over also. Now we even have all plastic cyclones, even by the company that promotes PVC will ignite or explode. What gives on that? Hobby DC blowers with the blower in front of the bag all use steel impellers. They have to, Al will not stand up to chunks of wood.

If you get into real life codes for big shops they sometimes require fire suppression nozzles and inside the shop dust bags are a big no no . Man, can you imagine if big brother decides to regulate us?


Something to think about for the guys who wear belts and suspenders. US Bureau of Standards of Mines reports " the impact of al. with rusty steel creates a thermite reactionand thus the possible ignition hazzards. Special care when Aluminum alloys are used in the present of steel." www.Rokdok.com/ucmsrc/factsheet.pdf Not sure that is a good address but you can Google for a source.

So even al is dangerous. We are all going to die! Yikes.

[Dave MacArthur]

Ok, Aaron gets the award for most interesting post of the night with his light-bulb resistor diode auto-gate di-lithium crystal hodge-podge! I understand just enough of what he's saying to be interested and scared all at the same time, but man do I want to putz around his shop and see what all he's got rigged up in there!

[Norman Hitt]

The don't stop/start your motor thing started a long time ago due to problems with the Asia made motors burning out. Early motors were terrible ,loose winding and not even dipped after winding. They also used Class A insulation which is the lowest temp wire insulation used. Any over temp and good bye motor.
That's pretty well fixed now. The quality of Taiwan stuff is amazing compared to only 5 years ago. I think they are sweating the China made stuff.

The Mod I mentioned is placing a resistor across the start capacitor. That bleeds off the charge and prevents the contact points from arcing during rapid cycling. That creates a lot of grief to the Cap and motor. Grainier sells the resistor kit for about $12 with 10 resistors Part # 2Mew1 or 2mew2.. Good deal if you have 10 motors. Not so good if you have only one motor. The resistor is a 15K, 2Watt, bought most anywhere for $1-2. I use a 240V industrial light bulb instead of the resistor. My motors are out side and the bulb tells me whats going on. They are lit when the motor is running, act as a brake when turned turned off, and bleeds the resistor down when the motor relay kicks in during cost down. Fun to watch as it cycles though the various cycles. For longer life of the bulb I use a diode in one leg. Never replace a bulb since I made that change. I bang the beast on /off at will with Auto gates . As a hobby guy working on one piece at a time I may turn the cyclone on/off 20 times or more an hour. Zero problems with caps or motor over a very long time.

Aaron, are you saying that you wire a 15k ohm resistor, (or equivalent light bulb and diode "directly across" the contacts of the Start Capacitor? Does the ohm size of the resistor need to change with the size (ie; hp) of the motor or is that 15k number good for any size motor? (I would guess the size would only change the discharge time)? Are you using a diode to restrict the flow? What size/part # is the diode, and if it is wired directly across the contacts and not to ground, I suppose it does not matter which way it is oriented, correct? What is the size/number/brand and where did you get the 240V light bulb, OR, how do you determine what size light bulb meets the 15k ohm requirement. I'm interested for a couple of possible applications.

Sorry for the Basic electronics Questions, but it's been 48 years since I got out of Electronics school in the AF and when I finished that tour and got out, I SWORE that I was going to forget everything I knew about Electronics except how to turn off and on the TV and a light switch and just concentrate on being a Pilot.:rolleyes: I think I accomplished that quite well about 40 years ago.:D

[Aaron Rowland]

Aaron, are you saying that you wire a 15k ohm resistor, (or equivalent light bulb and diode "directly across" the contacts of the Start Capacitor? Does the ohm size of the resistor need to change with the size (ie; hp) of the motor or is that 15k number good for any size motor? (I would guess the size would only change the discharge time)? Are you using a diode to restrict the flow? What size/part # is the diode, and if it is wired directly across the contacts and not to ground, I suppose it does not matter which way it is oriented, correct? What is the size/number/brand and where did you get the 240V light bulb, OR, how do you determine what size light bulb meets the 15k ohm requirement. I'm interested for a couple of possible applications.

Sorry for the Basic electronics Questions, but it's been 48 years since I got out of Electronics school in the AF and when I finished that tour and got out, I SWORE that I was going to forget everything I knew about Electronics except how to turn off and on the TV and a light switch and just concentrate on being a Pilot.:rolleyes: I think I accomplished that quite well about 40 years ago.:D
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I understand the difficulties. We are taught very little in schools about anything technical. A shame because we live in an increasingly technical world. What really irks me is companies run by sheet metal guys who have no clue on anything related to electric. Yet most listen when the sheet metal guy whose motivation is to sell more steel ductwork will say anything to increase sales will claim PVC and static electricity will kill you or at a minimum burn your shop down. Even writers in mags and books copy this bad info and publish it. The name for this is called" verification by repetition". Rod Cole, a PhD mathematician wrote an involved paper on static and why there was no danger at all. Totally ignored and he gave up and quit posting. His facts were dead on and indisputable. I notice you fly. Me too as a hobby. Baloney in this field will truly get one killed and there is very little of it as it thins the herd.

I suggest you Goggle Grainger 2MEW-2 and verify my comments on bleeders. The 15K is a nominal figure. you can use anything from 10K to 20 on any size motor. It's the cap size not the motor size that determines the R value. The 2 watt is minimum and 3 watt is better if you use a 10K resistor. It goes directly across the cap's terminals Your right the R determines the discharge time. Know nothing about electric stuff? It truly can kill you. If you don't understand the light bulb trick don't use it. Please find a friend who does to help you. I get very worried about posting anything on Electric power that might hurt some one. The new caps fail because the best chemical for insulation was taken off the market. It was replaced by veggie oil and has a short life. I keep spare caps on hand all all times, especially for the furnace fans. The most common reason motors won't start. Nothing like popping a cap during a snow storm on Friday night and no heat.

[Dan Hintz]

Posted in the other linked thread from the Oneida rep:

Turning the motor on and off sends the locked rotor inrush across the contacts of the centrifugal switch, doing so multiple times in a short period of time will eventually cause the switch to fail.
To me, this screams arcing contacts that eventually weld themselves together... a very common problem with relays at higher voltages.

Although I cannot dispute it, I fail to see how a bleeder resistor extends the life of the cap. Bleeders are typically used when it is desired to remove the charge on a cap for safety reasons, such as large power supply input caps, high-voltage CRT flybacks, etc. once the items has been shut down or disengaged from the circuit. I'm not a power guy (barely made a 'C' in power class during my BSEE days), but I see no immediate purpose for the cap to be discharged between power cycles... unless the cap charge is the cause of the arcing. An "unbled" cap will have a longer life than an empty cap if power is applied to it. I'm just not seeing the benefit yet...

[Dan Friedrichs]

The Mod I mentioned is placing a resistor across the start capacitor. That bleeds off the charge and prevents the contact points from arcing during rapid cycling. That creates a lot of grief to the Cap and motor.

Absolutely untrue. The small amount of energy stored in a starter cap is not large enough to cause "grief" to anything. For reference, 100uF is the typical size of a starter cap in a motor. The MAXIMUM energy it could possibly ever have stored is about 1 Joule, or roughly enough to light a 100watt light bulb for 0.01 seconds.


They are lit when the motor is running, act as a brake when turned turned off,

Again, absolute hogwash. How does the bulb brake the motor? While it is possible, it would require extensive modification to the motor and a bunch of switches.



and bleeds the resistor down when the motor relay kicks in during cost down.

What is a "motor relay"?

You cannot "bleed" a resistor.


As a hobby guy working on one piece at a time I may turn the cyclone on/off 20 times or more an hour. Zero problems with caps or motor over a very long time.

Electrolytic capacitors will dry out and go bad over time. You'll be replacing them eventually, no matter what.

Cycling the motor that often is bad for the starter winding (as I explained in the other thread on this topic that you started).

As an EE, let me proclaim in no uncertain terms that all of this is completely bogus.

[Aaron Rowland]

Aaron, are you saying that you wire a 15k ohm resistor, (or equivalent light bulb and diode "directly across" the contacts of the Start Capacitor? Does the ohm size of the resistor need to change with the size (ie; hp) of the motor or is that 15k number good for any size motor? (I would guess the size would only change the discharge time)? Are you using a diode to restrict the flow? What size/part # is the diode, and if it is wired directly across the contacts and not to ground, I suppose it does not matter which way it is oriented, correct? What is the size/number/brand and where did you get the 240V light bulb, OR, how do you determine what size light bulb meets the 15k ohm requirement. I'm interested for a couple of possible applications.

Sorry for the Basic electronics Questions, but it's been 48 years since I got out of Electronics school in the AF and when I finished that tour and got out, I SWORE that I was going to forget everything I knew about Electronics except how to turn off and on the TV and a light switch and just concentrate on being a Pilot.:rolleyes: I think I accomplished that quite well about 40 years ago.:D

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I didn't mean to mislead you. No, the light does not go across the cap. Its a different circuit. Having the bleed resistor across the cap does not hurt with the light bulb circuit but I don't use it because it's redundant. Grainger is a good company and doesn't promote scams as other claim here. An old saying is" never argue with a fool: onlookers may not be able to tell the difference". That's very good advice and that's the last of this from me on the bleeder circuit. Just one of many very controversial things I've done in my shop because it's fun. It's only a hobby you know.

[Ole Anderson]

Dan, thank you.

[Myk Rian]

A friend of mine called Oneida when his 3hp cyclone wouldn't start. He was told to not stop/start it too much, but leave it running.
The motor heats up and trips the thermal overload.

[Leo Graywacz]

If you have access to 3 phase power you don't have to worry about any of those things. I have a 36" fan that I start and stop all day that is 3 phase, never a problem. However, my DC is still 1 phase and I do respect Odeida's 6 starts per hour. Usually when I start it I will let it run for 10 minutes or so before I shut it down. If I use a tool requiring DC then it is already running for me.

[Ole Anderson]

If you have access to 3 phase power you don't have to worry about any of those things.

Maybe in a home workshop environment. But some of the same issues apply to 3 phase power, when designing larger well pumps, booster stations and sanitary lift stations, which are usually 3 phase, the number of starts per hour is always a design consideration.

[Greg Portland]

I know of no fires or explosions in hobby duct work including the infamous PVC static electric. That has been 100% debunked for a long period of time.Sparks can occur due to metal-on-metal strikes and cause a fire. Sources of metal could include a blade, metal in wood, cabinet material, impeller material, etc., etc. A spark sitting in a pile of wood shavings (your dust bin) can cause a fire, wouldn't you agree? Other sources of super-heated material would be a poorly adjusted saw (friction burning). Metal dust bins are recommended for these reasons.

You are 100% correct about wood+PVC dust explosions; I also agree that a spark will NOT cause a dust explosion in a home environment.

[Richard Wagner]

It seems to me that if there are thermal overload protectors the potential for a problem is taken care of. As long as you can turn it on, the thermal overloads have not tripped (ie, it has not over heated). If you have to wait for the overload protector to reset itself, you need to turn it on/off less frequently.

[Rich Aldrich]

3 phase power does not make the motor immune to limited starts and stops. Temperature and starting load is the issue. At the paper mill where I work, we have several 350 hp compressors with a limit of 3 starts per hour to keep from thermally destroying the motors. Heat is the issue. It destroys the insulation in the motor.

[Phil Thien]

3 phase power does not make the motor immune to limited starts and stops. Temperature and starting load is the issue. At the paper mill where I work, we have several 350 hp compressors with a limit of 3 starts per hour to keep from thermally destroying the motors. Heat is the issue. It destroys the insulation in the motor.

First, you do realize that the 350-HP is a scam, right? Just like those 6-HP shop vacs. You cannot connect a 350-HP motor to a 110-V circuit.

I'm just kidding, of course.

The real reason I'm writing this is to ask what huge air compressors are used for in a paper mill? And if you have any idea what kind of CFM/PSI #'s those things can generate? Just kinda curious.

[Chris Fournier]

I try to be reasonably efficient about my movements and processes in my shop but I turn on my DC when I need it - period. It's simple economics to me, motor servicing is far cheaper than changing my actions in my shop, unnecessarily batching processes, waiting for the hour to be up etc. so that my motor doesn't crap out. If I spend shop time babying my DC motor that is costed out at my shop rate - ouch over time!

I have a new cyclone in my shop now and it has a high quality Baldor three hp motor that drives an aluminum impeller. This is a far higher quality set up compared to my old offshore Delta DC which had a "1 hp" motor driving a steel impeller. I turned the Delta unit on and off as I pleased for well over 7 years and it never complained. I also worked in a larger shop setting where the DC was turned on and off as required and that motor was well over 20 years old before it had to be rebuilt.

I honestly think that most all of this concern is largely a non-issue brought about by reading the fine print as real world experience has not involved dead motors stacked up like cord wood.

[Tom Stenzel]

First, you do realize that the 350-HP is a scam, right? Just like those 6-HP shop vacs. You cannot connect a 350-HP motor to a 110-V circuit.

I'm just kidding, of course.

The real reason I'm writing this is to ask what huge air compressors are used for in a paper mill? And if you have any idea what kind of CFM/PSI #'s those things can generate? Just kinda curious.

In a manufacturing industrial plant a 350 hp air compressor is fairly routine. Where I work we have four 300 hp compressors to supply plant air.

Those are dwarfed by our 7000 hp main air compressor for the oxygen separation facility. 13.2 kV, induction start synchronous run. IIRC we're allowed two successive start attempts but if that fails we're out of business for at least an hour. Even with ear muffs/plugs I've lost a good chunk of hearing in that building.

The oxygen plant service engineers that I deal with routinely work on equipment that dwarfs ours, 30,000 hp and up electric motors.

-Tom Stenzel

[Aaron Rowland]

Baldor pretty much answered the question on my" Bleeder Resistor" thread post # 106. Ken went to the trouble of Emailing them and got an answer on Bleeders. So you can thank Ken for this verified answer.

Depends on the crowd but my philosophy is KISS or things should be as simple as possible, but no simpler. Looks like I talked down to the readers and I took some heavy hits for that. But I'll still keep it simple. No way am I going to publish the math with Coulomb and Gaussian theory and 4 pages long to prove a point.

So I'll again paraphrase Baldor and if some don't like it have at it. Baldor states that the determining factor for the number of starts is the start cap. Baldor allows 60 seconds of charge time per hour. So if it takes 2 seconds to reach 75% of the RPM that means 30 starts per hour. If it takes 3 seconds that means 20 starts per hour etc. But wait you say-- The cap recharges while the motor is spinning down and acting as a generator. But how long is that and how big is the charge? And there it goes again.

In one or more of my posts I alluded to the circuit I added to solve this problem on my cyclone. Baldor recommends a type of circuit to totally remove the run cap and the series wind during coast down and that's what I did but with my own twist. However just stick with the simple bleed resistor. Anything over the bleeder is a bit much for this site and I'm not going to go there. For most folks its not needed and the same can be said for the bleeder. If you have a shudder problem this simple resistor may fix it. If it does not then its time to go to the next step.

You can take this whole thing to the 3rd level and add another cap that charges every other time for faster starts. I have 7 different work stations and auto gates. So I restart every time I use a work station. That can mean 30 starts per hour or even more. That's zero problem for my motors and is fine with Baldor. If the supplier says 6 use 6. They have something wrong in the size of the motor or the price of the motor they use( in my opinion only.) If you don't spin up in 2-3 seconds I don't like it at all. Some motors weigh 100 lbs , others with the same HP may way only 50 lbs. Doesn't take a rocket scientist to spot the problem here.

After this bit, now I know how Giordano Bruno felt. Hey, I'm looking for a phone number on the net in Atlanta but all I get is a message that says not found. What gives?

[Ken Fitzgerald]

Aaron,

Sorry, but you severely misquoted the statement from Baldor.

Baldor says in some cases, a bleeder "MAY" mitigate the shudder experienced IF a residual charge exists on the start capacitor as it is reconnected to the start motor winding. A 3 pole contact to remove the start winding (nothing said about any series winding) completely from the circuit when power is removed will totally eliminate the problem.

[Chris Fournier]

Again back to real world usage and experience I have been at this game for about 20 years and have owned about 3 dozen motors of this size and I have yet to repair a single unit. I understand that not all applications are as arduous as a cyclone but many are.

I would definitley pigeon hole this entire bleeder resistor modification as "tweaking". Tweaking is an enthusiasts refinement of their gear which for the most part doesn't practically change anything but is very tidy in theory and is for the most part an engaging project for someone with the aptitude to undertake the work. Pride of accomplishment usually trumps any practical achievement. And of course there's nothing wrong with that outcome but I don't think that the tweak should be presented as a "must do" to the masses - think "elective surgery"!

[Ken Fitzgerald]

Chris,

If you read the reply I got from Baldor the engineer indicates that due to the potentially many different types mechanical loads, you can't predict if the suggested bleeder resistor will help or even be needed.

I agree with your statement it's something to consider IF you need it. I can honestly say on my Oneida DC, I haven't heard a shudder....remember I went deaf 8 months ago....but before that the 3 HP Baldor motor on it.....I don't remember hearing a shudder.

I may, however, consider trying a bleeder on my jointer.

[Chris Fournier]

Chris,

If you read the reply I got from Baldor the engineer indicates that due to the potentially many different types mechanical loads, you can't predict if the suggested bleeder resistor will help or even be needed.

I agree with your statement it's something to consider IF you need it. I can honestly say on my Oneida DC, I haven't heard a shudder....remember I went deaf 8 months ago....but before that the 3 HP Baldor motor on it.....I don't remember hearing a shudder.

I may, however, consider trying a bleeder on my jointer.

No I'm with you Ken regarding the "may be needed". My Oneida DC does not shudder either. The only machine that I've had that shuddered on slow down was an 8" Tiawanese jointer. I realise that drivetrains may mask this shudder in other machines.

Your point about the jointer is exactly what I was alluding to. We have plenty of other motors that have to spin up comparable or even greater loads than the cyclone and it's aluminum impeller. I realise that mass and overall diameter come into play but having actually picked up an Oneida impeller I can tell you that it isn't all that heavy. I have one shaper cutter that is a real beast and a four knife 16" cutter block in your jointer planer is no lilght weight either - I am not tempted to put bleeder resistors on either of these two machines but I am not an electronics tweaker either.

[Ken Fitzgerald]

Chris...I've worked in electronics since 1969....if I try it on my jointer it would be more out of curiosity.

[Chris Fournier]

Chris...I've worked in electronics since 1969....if I try it on my jointer it would be more out of curiosity.

That is tweakng defined! I shudder (pun intended) to imagine the thread if your experiment produces positive results!

[Dan Hintz]

Aaron,

Not only are you failing to make strong points, I don't think you'll make many strong friends with some of those comments...

[Phil Thien]

Aaron, your description of your shop sounds really impressive. Do you have any pics or links to movies with the light bulbs "doing their thing?"

Also, you mentioned you have some patents on this stuff. Can you provide some #'s so I can read up on your work a little more?

[Aaron Rowland]

Hi Phil, I've read about your separator. Nice work and I cannot think of a better way for a newbie to enter wood working. After one learns hands on how air works it will be a lot eaiser to move up the ladder with out a lot of mistakes. You really helped the community out by developing this idea. Thanks

To your questions and funny you should ask. I'm new at this exposure and posting thing. I talked it over with several wooding friends on how to publicize my shop. Very negative responses. Some put their own sites up and ran into a lot of problems. Hackers being the least of them. Takes a lot of time etc. The question was why would I want do this. The best answer I had was to show what a good dust collection system could do and how to do it. Wood workers don't even know how to test for CFM. The rest-, I didn't have a good answer to that and still don't. So I asked about just posting on some of the wood working sites. Again was told to forget it and while every one had a slightly difference story the consensus was site traffic was a 1/3 what it used to be and any thing you post that might be considered unheard of you will take a beating. I might add some are laughing at me now after reading this site. I still can't believe a simple resistor could generate so much heat. A hundred so posts and what was accomplished? Not much. A bit bemused by all this and even called a troll. First time that ever happened.

So right now I'm reconstructing my thoughts. I will not release pictures of my shop for several reasons, the first is patent protection. I've had ideas ripped of in the past by a simple picture. It won't happen again. A mag who had heard of my shop dust control approached me for an article . The contract placed every thing in their corner and none in mine so I could not own what they photographed and had no control on what they said. The payment was pitiful on top of it but that's not important at my stage in life.

Phil, the light bulb thing is not a topic for this site or any other after the resistor thing. No thanks.

Patents, I have a few but only in the field of the Electronic Business I owned which was not wood working or consumer based.. I still get royalties but that is about over. A bit of advice on patents. They are worthless for most unless you have a business using them. NIH prevents you from selling them. If a larger company then yours wants your work they simply make a small change and take it for free. Patent attorneys are very well paid and live well. One of my sons does that. To sue expect to pay huge sums of money and you will loose 95% of the time. The patent office almost never admits they made a mistake so it takes a civil court to fix that. Search for Jerome Lemelson if you want to see corruption at it's worse in patents.

Try to license a patent is difficult at best. Dr.Steve Gass who invented SawStop found that out the hard way. Google www.inc.com/steve (http://www.inc.com/steve) gass. I don't have the right address but google should find this. The article is " He Took on the whole power-tool industry". Terrific insight into the business world. Steve now says he wishes he never had thought up the idea. Made a lot more money with no head aches as a patent attorney. So sorry I can't help. Best regards ,

[Dan Hintz]

Aaron,

How did you file these patents? I find none under your name...

[David Weaver]

Steve now says he wishes he never had thought up the idea.

Yeah, right.

He could stop any time. Could've stopped any time along the way, too. Behavior isn't consistent with that self-pity comment.

[Phil Thien]

Aaron,

How did you file these patents? I find none under your name...

Dan, did you try "Aaron the Troll?"

[Doug Palmer]

Glen,

I am an Electrical Engineer and have been involved in heavy industry for just shy of 30 years. When you start a motor the inrush is typically 6 to 8 times full load current. The motor is trying to get to it's speed as quickly as possible. Naturally this generates heat in the motor. On a single phase motor the capacitor also experiences an increase in heat. What is wrong with heat? If allowed to get too hot it will melt the varnish that the windings are coated with and cause the current to short circuit instead of flow throught the coils. It is typically recommended not to start motors more than 4-6 times per hour. Motors typically have a cooling fan blade attached to the outboard shaft of the motor, so once it is running it cools itself off. Now why would a dust collector be any different than a saw or other equipment. Because the fan has to turn a fan wheel, which is much heavier than a saw blade. Also the saw blade is usually connected through a belt pulley system which can transfer torque while a fan wheel is often direct coupled. However, the main reason is because the air that we are moving is very heavy and requires a lot of energy to get moving. Thus the motor has to work much harder to start.

None of this is all that important to the end user. The important thing to remember is don't get your motor too hot. If you have access to the motor, put your hand on the frame. If you can hold your hand on it, then you are in no danger of damaging your equipment. If it is uncomfortable after only a few seconds of holding your hand on it, you need to let it cool for a while by either continuing to run or keeping it shut off. If the motor burns your hand (not literally with a blister, but makes you pull your hand back). Then the motor is overheating and you run the risk of potentially damaging the motor. Note that this is not intended to be an exact science, but rather a guideline to help you determine how often is too often. I have my own cyclone that I built from scratch and I turn my fan off after finishing a task. If I am going straight from one task to another, I will leave it run, but I usually have a little set up time between tasks for measuring and rechecking. I wouldn't hesitate to start my 5 hp motor 4 times an hour, but would hesitate to do it 8 times. It cost too much money for electricity to just leave it run when not using it.

I have tried to keep this in simple lay terms without trying to teach how to design a motor. I hope you find something useful in the thread.

[Alan Schaffter]

How many pages are we up to now? :)

I'll stay away from the electrical but as to patents, licensing and magazine coverage.

First I filed a "Provisional Patent Application" on something I designed. I was lucky enough to license it without a full Utility Patent issuing. Just maybe it will finally hit the market this year?!?!?! But patent or no patent, it is purely up to the potential licensee whether he will license something with or without a fully issued "Utility Patent". Often the licensee will foot the bill if he wants it patented. But, from what I read, you don't typically license a patent. You license the right to produce the design, and may or may not "assign the patent" to the licensee. Royalties (more properly licensing fees) are usually based on sales of the product, not on the patent and are paid as long as it is produced, assuming the contract (license agreement) was written correctly.

I must agree about the magazines (at least one of them) however- they want material to publish at little to no cost. After my shop won the WoodCentral/Woodcraft Top Shop contest, Woodcraft Magazine wanted to shoot a multi-page feature about it. My shop has bunch of good ideas (tips and other) that I regularly submit to the usual suspects and have had quite a few published. In addition to the main article, they planned to include a number of "take-aways" about individual features. Since many of the potential "take-aways" were/are tip-worthy, publishing them would eliminate their value as a tip. They refused to give me right of refusal and the pay was pitiful (the prize was nice!), so I declined the article.

But, that being said, there are plenty of other stuff I have posted here and elsewhere, like my autogates. I included details about them in a video I uploaded to the web. Unless a shop has a lot of "never before seen" stuff, I doubt it contains much if anything patentable.