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3 PH Position control vs draft control

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DRankin
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2002-08-27          41694


Does position control mean you can raise and lower the 3PH in increments? Or is there another term for that? What is draft control?



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Murf
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2002-08-27          41696


Draft Control is a system used almost exclusively on Agricultural equipment for maintaining the attitude of 'ground engaging' implements, such as plows, discs, cultivators, etc. It is basically a pressure-sensitive valve built into the upper link of the 3pth, as pressure increases and decreases against the valve, the 3pth is automatically adjusted to maintain the set point. The assumption is, that pulling a (for example) plow at a uniform depth will create a uniform pressure, going shallower would result in less pressure and going deeper would increase the pressure on the upper link. It is almost useless for the sorts of tasks a 'typical' compact is used for, box-blading for example, the system would not allow a constant cut since the accumulated material filling the box would cause it to unload instead of maintaining the cut depth. Hope this clears it up.... Best of luck. ....


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TomG
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2002-08-28          41719


Mark: I posted my explanation in the other hitch thread. To Murf's comment, I'll add that draft control has two levers. One adjusts the sensitivity of the lift to changes in draft. Decreasing the sensitivity means that it takes heavier drafts to trigger the lift.

The sensitivity to draft can virtually be taken out of the mechanism and then the hitch sort of works like position control. Full up on the draft lever raises the hitch for transport. In draft control the hitch flops when there is no draft (you can't stop in draft control).

The other lever is the position control, but it controls how high the hitch can go rather than how low like in position control. The position control is used so that draft control can't pull a plow clear out of the ground.

In terms of a hitch raising in increments, I don't think anybody is very successful at 'feathering' them. It's just not the nature of the beast. That’s why I virtually never touch the 3ph when I grade with a box blade--3ph movements just aren't precise enough and the timing is usually off as well. I control action of the box almost entirely with a hydraulic top-link. I mentioned something I called a 'centre-neutral' hitch in another thread. I've never used one, but just maybe they feather better than position control hitches. Since in the other thread I said I’ve never plowed with a moldboard, here I’ll say that I’ve never used draft control. Some experience huh?
....


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Art White
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2002-08-29          41775


A good question here Mark, let me straighten some things out fropm Tom's post. While using the draft control you drop you lift lever all the way to the bottom and adjust the depth with the draft control. That is the proper way to adjust your depth. It is very easy to use with a boxblade and works very good to the point that you can't beat the level you will have when done. Like with any other grading tool don't be a hog as you won't get to where you need to go, just a little all the way just like with a dozer. Getting a little more indepth and I haven't followed the compact tractors but on some the draft control doesn't work fast or sensitive enough to make a difference. Our big farm tractors run at less than a 7% load change with adjustments made by the seconds, some competition runs a 20% load change for it to moniter which at that point you have lost 20% of your pulling power often to late and you would be spinning your tires. ....


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TomG
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2002-08-30          41801


Some years back somebody made a comment that they used a 3ph backhoe on a tractor that was in draft control mode. The way the story went, about the first serious dig, top-link compression triggered the hitch into lift mode. The teller said the engine started labouring furiously and the locked down hitch groaning mightily. He bailed out of the seat and ran. The engine killed and part of the mount was bent. Once lift was triggered on a locked down hitch, lift wouldn't reduce the compression to take it out of lift mode. I guess that the locked-down hitch also was locked-up or the hoe probably would have flopped on the ground in draft mode.

I've wanted to try a box scraper with draft control. I think it would help keep from gouging at the bottom of hills. I have to feather the hydraulic top-link out as the box starts up a hill. But then I also think: Do I really want 'constant draft' lifting the box over bumps and lowering it into dips? Some draft sensitivity setting probably would work just fine.
....


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cdcole
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2002-09-06          42113


One point to note. Tractors such as the Ford 600 series and even the 8Ns had draft control fed through a spring behind the top link. It does work and well - only for plowing. As most of you know the 3 point hitch was designed by Harry Ferguson who teamed with Henry Ford to make a 9N in about 1939. All modern tractors use this basic design. In addition to the position control we have on the compacts - the old units - many of them had draft control - primarily to comensate for when the front tires go in a perpendicular rut. Questions? ....


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TomG
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2002-09-07          42124


I think large farm tractors tended to put the draft sensing mechanism on the lower link arms--same principal though. Regarding Ferguson and Ford, I wondered for awhile if the collaboration resulted in the Fordson tractors--sort of an amalgamation of the two names, but I was wrong.

The story I heard is that a son of Ford started a tractor company and then found he couldn't call them Ford until Ford Motors bought the tractor company. Given the story, I was surprised to find that Fordsons were made into the 50's, long after some of the N’s that always were simply called Fords as far as I know. I probably don't have quite all the story.
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kay
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2002-09-07          42126


" think large farm tractors tended to put the draft sensing mechanism on the lower link
arms--same principal though"

TomG
What tractor had the draft sensing mechanism on the lower link arms? And how could that possibly work? Seems the only way draft controlt will function is if the sensing (compression/tension) is in the top arm linkage. Then the sensitivity of the draft is done by either setting the top link in different holes or with a draft control lever.
Sure is a lot of confusion about draft control and mis-informing answers and poorly worded explanations (albeit very good intentions by the authors) just adds to that confusion. Communication is a difficult thing, but provides for interesting chat. ....


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kay
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2002-09-07          42127


A plagerized definition of the 3 controls on tractors is taken from another site, and comes from JohnMiller3.

Quote "Miller’s simple definitions:

The draft control is used to control the depth of the implement below the surface of the
ground…

The position control is used to control the height of the implement above the surface of the
ground…

Float is used to allow the implement to follow the contour of the ground surface… ....


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Art White
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2002-09-07          42128


Kay, I'll chip in here on this, for the most part any that are over 80pto horsepower or 100 engine will have lower sensing. Most of these tractors are using it for plowing and do not use the top link as they are what we call semi-mounted. Massy was the only one that kept top link sensing on larger tractors than those I mentioned. ....


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TomG
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2002-09-07          42132


Pulling a 3ph plow creates tension on the lower links and compression on the top link. Doesn't make any difference which one a sensor is on, but granted push may be a different principal than pull.

With due respect to John, if I read his simple definitions first I probably would have come to the same misconception I held for awhile--that draft control maintains constant depth for given sensitivity settings. I don't think it actually does that, but it's a good enough working definition--especially for people like me who don't plow and don't have draft control. I've said that before. I also might start looking for a float control. But, some explanations that work for some people don't work for others so who knows. It's probably a mix of explanations that helps everybody.

If I summarized somebody's comments and presented them as a model elsewhere I'd probably ask their permission to do so.
....


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MRETHICS
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2002-09-09          42195


The Straight Dope on Draft Control on 3pt.

You folks seem to have a good handle on what it is used for.

Now let me give you an idea of it's effectiveness........

It works on moldboard plows that are fully integral or semi-integral...........barely. I cannot find any other use.

Sure there are many integral (3pt) implements it could be used on, but what's the point? Mount depth gaugeing wheels, and it is pretty much not needed. The gauge wheels will work better, maintain a consistent depth, and even though you may have a flat tire once in a while, they are still less trouble.

The reason to use it on a moldboard plow is the fact that there is no really good way to mount depth gaugeing wheels on the front of the plow near the tractor. This is more of a problem on 4 bottom and larger integrel or semi integral plows because of the length of the tool. They usually have a gauge wheel on the rear. On shorter plows,(2 or 3 bottom) a gauge wheel mounted just in front of the tail wheel and to the left so it rides above the furrow (on land is the tech. term) and maintains consistent depth will work just fine.

Changes in soil type, compaction and moisture levels of the soil, will give false readings to the load control shaft that senses the draft and raise or lower the 3pt hitch arms to keep draft within set paremeters.There is an adjustment on the tractor to compensate for this, but in reality, in some situations, this sensitivity needs to be adjusted several times each pass.

If you are concerned with a consistent depth,( and you should be, because inconsistant depth with a moldboard plow, will leave an uneven surface)it is barely acceptable.

On anything but plowing, it ain't worth a dime, and with a plow, it ain't worth much more, but you ain't got any other choices on a 4 bottom or larger plow either.

I've been on tractors and plows for too many years to count..........that is my view.


....


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Art White
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2002-09-10          42217


Draft Control is a viable way to keep a back blade from grabing to much fill for the tractor to pull, with a box blade it works just as well. It would also keep a backblade from bringing up the lawn while removing snow. It will keep the front of a 6 btm plow from coming out of the ground while cresting a hill or let it go down while in the bottom of a gully. It will raise the hitch if you catch a large stone to help keep from breaking the plow. There are differences in the hitches as was stated in an earlier post. Some repond with less than a 7% load change and some take more than 20% to repond rendering them useless or nearly so. Some will react in less than a second, some only in seconds often to little to late. Do the bulk of compact tractors need it for there applications? No. ....


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Murf
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2002-09-10          42226


I'm going to wade in on this one again. With all due respect to Art's MANY years in the business, I want to state that I did not mean the draft control wouldn't work on a compact. I meant it was USELESS on a compact, it certainly will function. Now to clarify what I stated.

The draft control system works PURELY based on the LOAD applied to a trigger mechanism, which operates a valve. It is designed to maintain a constant load on the 3pth. The problem with trying to use this system for 'our' uses is simple, in most cases we want either a load that is constantly increasing (scraping dirt up, plowing snow, etc.), or constantly decreasing (spreading dirt, etc.). With draft control, to use Art's example for plowing snow, as the load increased (the snow piled up) it would change the draft (dumping the snow). In the alternative, setting it more aggressively, it would not know the difference between a full blade of snow and ice, and a blade with no snow behind it, just the (former) lawn.

In practical experience, if it was the be all & end all of working with a 3pth implement, it would be offered (and used) on most Compacts, it isn't. It is on some machines which are primarily Asian-designed where a 20hp. 4wd. Compact is a "full-sized farm tractor" and they are used for 'ground engaging' work.

Best of luck. ....


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TomG
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2002-09-10          42227


Thanks for the explanations Art and Mr.E. They are similar to my impressions. In myself, I recognize that questions about what something does and how it works are pretty much the same. Most other people make a greater separation between the two. That may lead to lengthy unfocussed explanation from me--especially since these subjects are still pretty much learning exercises for me. They do lead me to what I think are better understandings of things, and I hope they work that way for others who are interested, I've never been happy with using black boxes myself. Constructive comments from yourselves are essential to fill in the gaps and head off excesses of meandering. Thanks.

So, in terms of how it works, my reading of a repair manual describes oil flow as directed to either the piston or shaft side of the lift cylinder. That sounds like double acting cylinders on loaders etc. I've never been certain if the lower spool in draft control produces down-pressure or is passive like in position control.
....


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Art White
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2002-09-10          42228


Murf, just as Mr. ethics stated, plowing is one of the best places for the draft control. I do see farmers not useing it on some make tractors as it is to little to slow and to late. While plowing my driveway for snow I was normally at or about 3 to 4mph. I set the draft a little lighter than when plowing and as soon as the blade hit the turf up it went and I didn't leave but a little mark on the lawn. I have used it for a box blade while moving dirt. I found that as the box blade was filling on about a 500' run I did have to icrease the draft but it was far easier than tring to regulate with the raise and lower lever as the fellows before me had tried and left ruts and piles as they couldn't pull it that far with the load they were working with. There is a big difference in the caliber of the draft controls used on tractors and that will make a big difference as to usefulness of the control. ....


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MRETHICS
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2002-09-10          42239


TomG, all the rocksaft cyl. in 3pts. that I know about are passive. There could be some I don't know of.

And Art, you are correct, the draft controls available today are much better than those 25 years ago. And I have used mine on the box a few times just as you described, sometimes it worked very well, it just depended on the situation, but it viability was inconsistent. I found a better way...........Hyd, top link. This gave me much better control.

To Murph..........you uderstand excactly what I said.

Hey!!!!!!!!!!we are all kinda right...........I love it when that happens ....


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TomG
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2002-09-11          42265


I believe that a Russian tractor, Belarus or something like that, has a hitch that produces down-pressure. That's the only one I've heard of.

I didn't think that pushing down on a plow, even if the draft did decrease, would be a great idea for plowing. It seems doubtful that the hitch could react precisely enough to keep down-pressure from unloading the rear wheels. Guess I've got to go back to my repair manual one of these mornings to sort out their description and figure out why it sounds like a double acting cylinder.

Another of these 'how does it work ' things I'm trying to figure is the position control lever on a draft control hitch. I believe that it limits how high the draft control hitch can raise when lift is triggered. I haven't nailed down the idea, but I imagine that the hitch goes into a passive mode at the position control level where it can float up like a position control hitch. Having a plow held down by the hitch sounds like a bad idea.

As soon as I heard the ‘constant draft idea’ sometime ago, it worked far better for me than the ‘constant depth’ idea I heard earlier or the ‘lifts over hard spots’ idea I heard even earlier.
....


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kay
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2002-09-11          42282


TomG
Have you ever plowed ground with -say- a 2 or 3 bottom plow on a 3pt hookup? I mildly suspect you have not, as I would think a whole lot of the mystery about draft control and positioning would drop in place otherwise.
Only curious to know. I don't mean this to sound un-friendly in any way. Just trying to better understand your curiosity and wonderment about this subject. ....


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TomG
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2002-09-12          42306


I did say previously that I don't plow and haven't operated a draft control hitch. I'm pursuing sort of a hobby, which is figuring out how things work.

Let's see if I can briefly say what's going on with me. I said that the question of what something does and the question of how it works are pretty much the same question for me. That's a mechanic’s orientation. I need to have a mental image at the level of 'this rod pushes this spooling valve this way which opens this port and feeds pressure through this passage to this valve etc.' to know how it works.

I've built most of an image by digging details out of my repair and parts manuals plus a few questions here. However, the manuals aren't intended to be educational, and I haven't found a basic tractor mechanics text.

When I ask questions like 'does the lowering spool power down the hitch, or does the hitch float above the position control setting' it's because I don't think a powered down hitch or one that was held below a certain point would work very well. However, if they really do, then I eventually would go back to looking in my repair manual for the particular valves, passages and control mechanisms that would allow that type of action. I realize that a 3ph plow tends to dig in at the bottom of a hill and lift out of the ground going over the top and a draft control hitch doesn’t. That’s what draft control does among other things. I’m trying to figure out exactly how it does it.

I realize this process over a discussion board is a bit messy and that not everyone needs or is interested in this type of thing. On the other hand, having dug this sort of stuff out by sometimes plaguing this board with obscure questions and meandering descriptions has enabled me to occasionally identify what's wrong with somebody's tractor.
....


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Art White
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2002-09-12          42311


Tom, this is messy. They use bending bars or springs on mechanical, and load cells if using electronics. Depending on the quality, depends on the sensitivity and response time. ....


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MRETHICS
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2002-09-12          42315


Yes, how draft sensing works is very messy. Art is excactly right on the various ways in which systems are designed. Toooo much to get into great detail on this forum, but the newer electronic ones are much simpler to explain.

Just as Art said, The electronic type use load cells, potentiometers, micro processors and computors. Electronic scales....so to spreak. I think you understand that technoligy TomG.

Let ma also add here, in my humble opinion, the newer electronic type work much better than the old mechanical type. However, as much as the electronics have gained in the effectiveness of the device, it has also caused an equal loss in reliability.

3pt's can be rendered in-operable due to faults in the draft control system. This creates a big problem since the draft control is seldom used. This problem is not restricted to brand. There are older tractors in operation with malfunctioning draft control, but the hitch works fine because the control is shut off. In alot of cases, in the electronic models, that scenario will not work.

Oh well, ya win some, ya lose some, but technoligy marches on. I beleive the electronics will catch up in the reliability area soon enough, if not already. ....


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Murf
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2002-09-12          42319


Tom, the draft control system is merely an automated (mechanically or electrically) 3pth control lever, doing exactly the same as you moving that familiar little lever. It just happens internally, based on pressure, or the lack thereof on some portion of the 3pth linkage.

The most common (IMHO) of these is an internal, spring-centered valve inside the diff. housing, to which the moveable upper link mount connects. Increased 'pull' on this valve (more weight on the upper link) is taken as reduced load on the implement, such as the plow coming out of the ground, and it lets the 3pth lower. Conversely, increased 'push' on this valve (less weight on the upper link) is taken as an increased load on the implement, such as when the plow goes to deep, and it lifts the 3pth.

Hope that makes it a little clearer, and as always...

Best of luck. ....


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TomG
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2002-09-13          42339


Thanks folks. If I can take Murf's idea of an automated position control as a good metaphor then I'd conclude that draft control doesn't power down and does float up. That's the way I'd expect it to work. Now I can figure out why my repair manual doesn't seem to describe it like that--but I promise to do it silently.

The automated hitch is an idea I also had but didn't know how far the comparison could be pushed. I guess the part in my manual called the 'plunger' is my hand on the lever. An earlier very brief description from somewhere might be taken more like an automated loader valve and I knew that conclusion wouldn't be right.

Messy as draft-control might be, and certainly this discussions as well, I hope some people formed better ideas about how hitches work. For a time in my early days of tractoring, I thought that lowering my box scraper to the ground with the 3ph and then extending the hydraulic top-link applied down-pressure. In my case, simple descriptions read when I had very little experience led to simple mindedness. Simple and brief isn’t always adequate.

I think we've done pretty well here and maybe a few people will avoid the misconceptions I held for some time. But it would be good if I kept my meanderings about the relationships among parts more to myself. This Board has been very good for a long time at giving people with various orientation room to follow them. Participants also have been good at recognizing when following their own orientation becomes self-indulgent and knowing when to stop. Stopping is here and now for me and I hope I haven’t run the sign.

....


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DRankin
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2002-09-19          42661


This is a great overview that I borrowed from the TractorSmart.com web site

Tractor Three Point Lift Types

Let's start by defining what a three point hitch is. Tractor three point hitches consist of; Tada! three major components. They are: the left and right lower lift arms (those long things with the balls in the end, that are sticking out the back of the tractor), and the top link; usually a three piece adjustable apparatus with a central body and two threaded ends with balls, one of which attaches to the tractor, and the other which attaches to the implement. The overall length of the top link is adjustable via the threaded ends. The sole purpose of the three point hitch is to place, and hold, the mounted implement in the desired position to accomplish the job at hand. As you may have guessed, there are many different types of systems available to get this done. Some are quite simple, while others are extremely complex. In the simplest form, a hydraulic pump supplies oil to a control valve. The position of the control valve determines where the oil goes next. If the control valve is in neutral, the oil is simply directed back into the reservoir (transmission housing). If raise is selected, the oil from the pump is directed, by the control valve, into the lift cylinder, causing the lift arms to rise. If lower is selected, the oil from the pump is directed, by the control valve, to the reservoir (just like neutral); however, a passage is also opened which will allow oil to escape from the lift cylinder, allowing gravity to lower the lift arms. Many of the smaller compact tractors are, in fact, just that simple in lift control. They use what might be termed...

Non position control. This type of lift is simple to build, easy to troubleshoot/repair, and potentially very aggravating to use, depending on the implement. Let's assume you are using a rear grooming mower that is supported, while in mowing position, by four caster wheels (one at each corner of the deck). No sweat. Just shove the lift lever to the down position, and the casters take care of it from there. Now, suppose you want to put your box scraper on and put a nice finish grade on a yard. In order to do a good job, it is important to have finite control of the height of the box scraper. The problem is, you must manually return the control valve to neutral at the very instant the box scraper arrives at the correct height. What usually happens is that the box has already gone past where you want it to be before you can yank the control valve into neutral. Well dang, I don't want to go through that. Enter….

Position control. This nifty lift type has some extra parts called feed back linkage. This linkage can be either internal or external, yet it's purpose remains the same. Feed back linkage serves to return the control valve (automatically) to the neutral state as soon as the lift arms reach the point selected by the relative position of the lift control lever. Whereas the non position control type only has three positions (raise, lower or neutral), the position control type allows an infinite number of lift arm positions, from all the way down, to all the way up. If you regularly perform tasks that require precision, repeatable lift arm height control, definitely get the position control type of lift. Now, take a deep breath and get ready for….

Draft control. Draft control, while not essential, makes life a little easier when plowing, sub-soiling, or using other ground engaging implements. For illustration purposes, let's assume we want to go plow up the back forty. We've mounted our plow to the three point hitch and adjusted things so that the plow will run straight and track properly behind the tractor. A note about plowing- if you have adjusted the plow properly, you should not have to use the stabilizer system to keep it running true behind the tractor. As you let the lift arms down, and begin to move forward though the field, the plow will start to enter the ground. As the plow continues down, traction and horsepower requirements increase. The natural tendency is for the plow to continue down until the tractor either loses traction, runs out of power, or the lift arms reach their lower limit. It is very unlikely that the latter will happen. We want to be able to plow at a reasonable depth without straining the engine or having excessive tire slippage. We also do not want to have to continually fiddle with the lift controls, raising and lowering the plow by small amounts, as ground conditions vary throughout the field. That's where draft control really helps. Draft control senses the amount of strain that the tractor is being subjected to from the plow. If the strain exceeds a predetermined level, the draft control will automatically raise the plow just enough to restore normal loading of the tractor. After you get past the hard spot in the field, the draft control automatically returns the plow to the pre-selected, ideal depth. There are two main types of draft sensing in wide use today. They are: lower link draft sensing, and top link draft sensing. Both achieve the same end result, and much discussion could be made over which is the best method. Generally you will find lower link sensing on larger, higher horsepower tractors. In the case of lower link sensing, the front of the lift arms are attached to a common bar that flexes with variable loading to impart movement to linkage that is ultimately connected to the control valve. There are also tractors on the market that incorporate an electronic lift control system. With these, the lower draft bar contains a strain sensor which sends a signal to an onboard computer. Movement of these electronic bars is almost undetectable to the eye. For tractors that utilize top link draft sensing, there are several methods in use to transmit draft load information to the control valve. For a large portion of North American style tractors, there is a rather large (usually internal) coil spring, which is compressed (by the top link) as draft load increases, and relaxed as the load diminishes. This compression/relaxation causes movement in the draft control linkage, thus changing the position on the control valve, raising and lowering the lift arms as needed. Other tractors (namely European style) have a massive leaf type spring between the top link and the lift cover. Still others use a torsion bar that is actually twisted as the top link moves toward and away from the tractor. Now, with all of this draft action going on, we've got to slow the lift system down some, or we'll end up with a rapid, out of control oscillation of the lift arms going up and down. This is accomplished with something called….

Response control. Response control (in most systems we know of) simply serves to control the rate at which hydraulic oil is allowed to escape from the lift cylinder. By slowing this rate, we minimize undesirable oscillations that would otherwise occur. Response control has no effect on rate of lift, and that is good, because we want the plow to raise quickly when we hit a hard spot. However, if we let the plow go back into the ground at an uncontrolled speed, we will end up pulling a plow that jumps into and out of the ground. We have to give the system a little time to settle down somewhere in the raise/lower cycle, and that is the function of the response control.

To get the maximum benefit from draft control, you must use it the way the manufacturer intended for it to be used. Do you need draft control? On the smaller tractors, probably not, as these tractors are rarely used to do much plowing. On larger tractors, it is pretty much standard equipment anyway, so the choice is made for you.

Regardless of what tractor you now own, or may be considering as a future purchase, take a little time to completely familiarize yourself with it's operating characteristics. You'll enjoy it much more!

Click here for a detailed explanation of the most common Massey Ferguson Lift System.



Hitch Category Top Link Pin Diameter Lower Link Pin Diameter Lift Arm Spread (A) Vertical Height (B)
0 5/8" 5/8" 20"
1 3/4" 7/8" 26" 18"
2 1" 1-1/8" 32" 24"
3 1-1/4" 1-7/16" 38"




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3 PH Position control vs draft control

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
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2002-09-20          42683


Mark: I read it--each and every word. I think the effort is great and illustrates what I think we do well on this Board. Participate in each other's learning and give room for each other's particular orientation. Some people just want pat answers, and those are provided as well. Myself, I write here partially for my own learning, and often I write a lot. I find that when I get it straight in my mind, what I write gets shorter.

I’ll see if I can make a couple of comments and stay with 'short' as well. The first is that the 3ph was invented partially to reduce tractor upsets due to sudden draft increases. Draft puts compression on the top-link, which attaches to the tractor above the axles.

Almost all hitches are neither held down nor do they produce down-pressure. An implement on a position control hitch will ride over a bump and lift above its position point. A passage opens so oil can be drawn into the lift cylinder so the hitch can rise.

In draft control, the idea of 'returns to its normal position after lifting over a hard spot' means 'returns to the level that results from the combination of typical soil conditions and the draft sensitivity setting. The feedback mechanism on draft control requires some draft to keep the hitch in neutral. Low draft triggers the lowering spool much as high draft triggers the lift. However, there's no depth setting in draft control like on position control. Stop a tractor in draft control mode and the hitch lowers as far as it can go.

The position control lever in draft control adjusts how high the draft control can raise the hitch. Without experience here, I'd have to guess that unless the lift was limited, then hitting a hard place while going over a hilltop might pull a plow out of the ground. The position control takes the hitch out of lift once a set level is reached, but I think that the hitch can float above that point (similar to position control). I'm guessing here because that's one of the details I don't have completely straight. However, having a hitch held down doesn't seem like a good idea.

Anyway, I hope these comments add to your effort. They certainly aren't intended to detract. Guess I sort of failed on the ‘short’ buz. Oh well, maybe next time.
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3 PH Position control vs draft control

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MRETHICS
Join Date: Jul 2003
Posts: 190 Star City, Indiana
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2002-09-20          42694


very good very good......Mark and Tom. Very good explainations and a major effort. Well done!

And within your posts, lies my lifetime problem with draft controls.

If the tractors attitude is changeing due to un even ground and the draft control is used to maintain plow depth...wellll....cool...I like it.

But if it raises the plow in a hard spot in the field...well.....nutts!!....That was the main purpose I chose to plow that field in the first place.....to break up compaction in the rootzone of the soil structure. If I cannot do that...why am I out there? Practiceing converting diesel fuel to noise?

I'm not trying to be sarcastic. Over ther years, I've watched as my neighbors were pulling larger plows on the same tractor as ours, and bragging how much better thier's pulled. Explainng to them what was actually happening never worked.

It became so frustrating, and we were the butt of a few coffeshop jokes, I snuck over to the neighbors and disabled the draft control on his 4020 Deere in the middle of the night. The field he was currently plowing was flat as a pancake so it would do no harm.

He fought it for a couple hours, finally he dropped to a lower gear.

I stopped at the fence and talked with him mid morning and shared a cup of coffee from my thermous.

"Ground sure is hard this spring" was his only comment.

I let him off the hook before he called his dealer to complain about the sudden loss of power.

He didn't speak to me for quite a while, but I did notice overnight his plow was a bottom shorter the next day...same size as ours...what a coincidence! ....


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3 PH Position control vs draft control

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TomG
Join Date: Feb 2002
Posts: 5406 Upper Ottawa Valley
TractorPoint Premium Member -- 5 Tractors = Very Frequent Poster

2002-09-22          42770


Mr.E: I didn't get around to thanking you for the kind words yesterday. Guess thinking about the steering question sidetracked me.

I chuckled about the neighbour's draft control. I do remember my cousins bragging rights about what could be pulled in which gear. I'll use the story as an excuse to practice concepts. I guess if draft control produces constant draft, it stands to reason that a light draft setting takes less power and can use a higher gear.

I suppose that a very heavy draft setting may seldom trigger the lift but then a tractor may have to use a lower gear to pull it. I know that lower gears take a lot more time in big fields and a lower gear was the last thing my cousins wanted to do. A smaller plow might get the job done faster than a lower gear.
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