540 PTO RPM and engine longevity

[rambler]

What hp is your tractor? 10 or 15kw is a pretty good load. It is possible you will be lugging a <25 hp tractor pretty badly if you run it at less than full throttle on that load.

This would _greatly_ increase the wear on the engine.

What is max engine rpm for your tractor? Generally it is more than pto speed.

You should be able to run pto speed days & days on end at rpm speed. It's what a tractor is designed to do.

Lugging the engine - now that is hard on them. If you put too much load on it at 1/2 throttle, it won't be able to get into it's torq bubble, and the poor thing will really strain. Combines come with a throttle much like a lawn mower - pretty much idle or full throttle. No need to ever be in between, and not really good to be running in between.

Hardest of all is starting them. Most folks don't realize leaving it run an extra 20 minutes is better for them than stopping & starting them....

If you put a multiple belt pulley on the pto shaft & apply enough pressure to eliminate slippage, you will be deflecting the pto shaft & putting a lot of wear on the tractor pto assembly. Likely to wear that out rapidly. You would need a supporting pillow block, & it is difficult to line one up perfectly, so you need to put in a flex joint of some type & 2 pillow blocks on your jack shaft.....

A vbelt is equally as dangerous as a chain. Do not forget this. Ever. The teeth look worse. But the belt is every bit the equal on catching someone. I have too many 9 or 5 fingered neighbors.........

Not saying you don't have a good idea, but if you think it all the way through, things were meant to run one way.... Be sure to look at all the considerations.

--->Paul

 

[Egon]

Just wondering if the bearings on the generator and tractor end are designed for the proposed task.

V belts will work and last much longer than a chain drive.

Egon

 

[khd]

What about a gear box? 10:1 at 2200+-100 rpm is about right for 3600rpm at the head if a 27% reduction in engine rpm corrolates to a 27% reduction in pto rpm.

PTO shaft to box, box to head.

Regards,
Kevin

 

[plaindave]

If you are going to belt drive a generator you need a two bearing alternator. My best guess is that a PTO generator would be that style, but I'd ask to be sure.

With a single bearing alternator when you got the belts tight enough to not slip you would have so much side load on the bearing that you would burn it out in no time.

The belt drive system would be very easy to do. Solid mount the generator on a base with a pulley and shaft assembly with pillow block bearings on both ends next to it. Belt drive the generator from the shaft, and then drive the shaft with the PTO of the tractor.

If I wasn't clear I can try to come up with some drawings. But you set your belt tension once and then just hook up the pto shaft like you would for any other attachment.

 

[getut]

Yes.. lets see if I can explain what I have had in mind:

A steel framed table with 4 legs. When the tables legs are on the ground the table top would be slightly lower than the PTO output on my tractor. Mount the genny head off to one side on the tables top. Use a pulley, pulleys, or sprocket on the input shaft of the genny head. Cut a slot in the table top large enough for a much larger diameter pulley, pulleys or sprocket to sit across from the same thing on the input shaft side but centered (left to right on the PTO output of the tractor). Use pillow blocks as you said to attach the large pulley to the table top but extend a splined shaft toward the tractor from that large pulley.

Then a standard PTO shaft could be used to drive the whole system. I would also have some sort of frame on the table to hook to my 3ph so I could easily lift and move the table.

Drop it to where the legs are on the ground, engage the PTO, throttle up and voila.... instant spewing of violent spinning death (parts)... err.. whoops... got carried away there. At that point, hopefully production of useful electricity.

Getut

 

[RonR]

I don't know about this.............

I build a lot of stuff, and some of the stuff I build requires some post-completion rework. As complex at this thing is becoming, if it were me, I'd buy the PTO thing built for this task and be done with it.

By the time I build it and bought double the number of bearings I'd planned for, multiple chain and belt drives, fabricated several sets of shields to minimize the death and destruction, I'd probably have exceeded the cost of the store bought unit.

That, plus if you don't have the bearings just right, they won't last and you don't want to be doing a major overhaul in the midst of Hurricane XXXX.

Just my two cents..........
Ron

 

[DVerbarg]

<font color="blue"> A vbelt is equally as dangerous as a chain. Do not forget this. Ever. The teeth look worse. But the belt is every bit the equal on catching someone. I have too many 9 or 5 fingered neighbors.........
</font>

I'm an example of not taking a v-belt seriously enough and lost part of my right-hand first digit as a result. Even if you are careful be sure to have guards in place - kids can be very curious - regardless of your use of belts or chains.

Sounds like a fun project. Wish I had the time and/or energy to do the research and build projects like this on my own but end up usually buying the prefab units. Built a new house 4 years ago and still have not hooked up my little 5.8k generator yet. Been thinking that the new house requirements may warrant getting a PTO generator instead /forums/images/graemlins/grin.gif.

 

[Soundguy]

</font><font color="blue" class="small">( except for an 18" disk of spinning death (with teeth) )</font>

Sure.. belts and sprockets may sound bad.. but have you ever seen what a 20' belt does when it flies off a belt pulley?

Besides.. what makes you think a sprockets gonna fly off?

Soundguy

 

[getut]

Actually I'm just being funny.. I usually do pretty good work when I have the tools available. I can beg or borrow a welder and either personally own or have access to all the cutting/grinding/drilling tools needed to create the table and 3ph attachment frame.

Genny heads are relatively cheap (even dual bearing ones) and pillow blocks and bearings are also cheap. The only area I am hurting on, that is also the only thing making me hold back up till this point, is the accessibility of the necessary sprockets or pulleys. I don't have access to anywhere near the level of equipment to fabricate these myself (especially a sprocket or pulley with a stub of a splined shaft sticking out of it).

As for those of you who mentioned cost. Keep in mind that cost savings isn't the reason I am actually contemplating this task. It is purely to get the RPM down a little so that I don't have to wear earplugs inside the house in a power outage.

Looking at the specs on my CK20 engine.. there is very little difference in torque and HP output at 2200 RPM vs 2800 RPM. There is however at least twice as much noise and at least some additional wear and tear. I know I already discussed that point earlier in the thread and I do believe you guys that it isn't that big a deal, but if you've ever heard or driven a CK20, the difference between 2200 RPM and 2800 RPM is incredible in all the bad ways, with only a modest gain in HP and an actual loss of torque. Maximum torque is somewhere around 1700 RPM, so I should have plenty of torque reserve running at 2200.

Getut

 

[Jim_Fisher]

</font><font color="blue" class="small">( The only area I am hurting on, that is also the only thing making me hold back up till this point, is the accessibility of the necessary sprockets or pulleys. )</font>

Tractor Supply carries Weldasprockets and the appropriate chain as does Surplus Center.

Surplus center also carries a lot of other neat power transmission stuff.

</font><font color="blue" class="small">( I don't have access to anywhere near the level of equipment to fabricate these myself (especially a sprocket or pulley with a stub of a splined shaft sticking out of it).
)</font>

I would think that a keyed shaft would be a whole lot simpler to make and would work just as well.