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Syncronizing the PTO driveline
Could someone please remind me how to "syncronize" the PTO driveline to reduce harmonic distortion on the generator - I thought there was a thread on this board but I cant find it. I have a metric driveline (curved triangular tube sheath - for extension - on the PTO, thus three possible orientations, and two cross bearing thingys on the opposing universal joints. I realize this only applies when the driveline is operated such that there are bends in the universal joints (height difference) but need the information anyway.
Many thanks Ann
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Syncronizing the PTO driveline
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Syncronizing the PTO driveline
I wish I could help, but I just don't know.
I know that the better gen-sets have a low harmonic distortion number, but I always assumed that was something contained within the unit itself and not related to the PTO drive line.
I do know that the drive line should run as straight as possible to the generator.
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Syncronizing the PTO driveline
Soory Ann, I didn't see this until just now.
It's one of those cases where a cutesy saying helps to remember something.
"The entire driveline must see eye-to-eye or the parts will never get along with each other."
The "eyes" or loops that hold the U-joint on any given shaft must be in the same plane, if they are rotated out of phase it will cause a harmonic vibration.
Your driveshaft should look the one below.
O=================O
If it looks like the one below, it will never run smooth.
O=================[
Best of luck.
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Syncronizing the PTO driveline
Good info Murf. I just want to confirm you are saying the "X's" that form the CV joints need to line up.
I wonder if you can run your PTO drive shaft out of phase in Sedona, AZ and not notice it.
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Syncronizing the PTO driveline
Mark, you are correct.
It is the pivot points that the X's form that must be in unison.
I forgot to mention, extended use of a heavy, out of synch. or even just bent driveshaft can also get spendy after a while. Likewise a badly out of balance implement like a bush hog, even if just from broken or bent blades, can cause damage to the tractor's output shaft and the bearings it runs on.
I saw a guy bush-hogging a field this summer, the unit was shaking so bad you could see the deck moving from the road. I stopped to point it out to him. When we lifted the deck up there was about 2" of one blade broken off!!!
He thanked me and asked for a business card. He called me the next day to thank me, he spent $40 on a new set of blades and was astounded at the diiference. He said the numbness in his feet had even stopped!! LMAO!!
Best of luck.
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Syncronizing the PTO driveline
Most single u-joint drive shafts (vs. a double caradan-type) with a joint on each end are designed to run at about 2 degrees total each out-of-line with very slight or no vibration. At about 5 degrees total or 2.5 degrees each is when you start to see vibration.
The vibration is caused by the joints being out of phase, that is, like was mentioned above the yokes on the ends should form an X to cancel the effects and be in-phase. Out-of-phase is a condition where as the shaft turns the yoke it drives the u-joint at 1.5 RPM's times faster than the input speed through 90 degrees of rotation. The next 90 degrees it slows down by 1.5 times RPM, speeds up, and slows down resulting in vibration.
As an experiment, take a 1/4" or 3/8" ratchet socket universal with two extension shafts and rotate one shaft as the "input" with your fingers. Allow the other "output" shaft to make a sharp angle and observe/feel the output shaft--it will feel like it's jerky or speeding up and slowing down every 90 degrees. If you were to connect another unversal to the input shaft and rotate it, to a certain degree, the output shaft would be nearly vibration-free.
To cancel or reduce vibration, you can have a double cardan joint on one end (which is two u-joints housed in a cast housing) and a regular u-joint on the other end.
Short of that, you may want to consider using a "constant velocity" or "CV" joint that uses balls in a cage (used on front wheel drive cars) that deleivers vibration-free power. There are Ag applications for these type of shafts with CV joints but can be expsensive.
U-joints are not considered "constant velocity" by definition since they are by nature out of phase if not phased with another u-joint on the other end of the shaft.
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Syncronizing the PTO driveline
OK Thanks guys, I now have mine looking like this:
]---------[
such that the opposing yokes on each shaft end of the universal joint are in the same plane.
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Syncronizing the PTO driveline
Pull the shaft apart and turn one end 90 degrees and stick it back together. Like this:
O---------------[
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Syncronizing the PTO driveline
Boy am I confused.........
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