I'm thinking about a B series Kubota. One of my considerations would be a PTO generator. I first thought a gear trans would be better as it would be less inclined to overheat with hours of continuous usage. But looking at the B 2601 it appears that the hydro oil is cooled in front of the radiator. Is this correct? If so that would mean that the hydro transmission oil is cooled down while the gear trans would just be losing heat out of the transmission housing. Has anyone actually hooked up a generator to a hydro trans tractor and used it for 48 to 72 hours straight?
static load; Hydro or gear trans?
- Thread starter bilrus61
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TMGT
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Both the gear and hydro tractors have coolers, the cooler is for all the hydro fluid and is actually circulated by the tractors hydraulics not the hydrotatic trans.
Only advantage to gear for static use would be a small increase in efficiency from slightly less load from the trans.
Only advantage to gear for static use would be a small increase in efficiency from slightly less load from the trans.
aczlan
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In my opinion, you will not have a noticeable difference between the two. Where you see the difference with a hydrostatic is when it has to move the tractor in addition to running something on the PTO. If it's stationary (in my opinion) there will be no noticeable difference between the two in fuel usage.
Aaron Z
Aaron Z
CalG
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Looking at the Service manual for the B7200 (old, I know) The PTO does not make use of the hydrostatic drive. The PTOs, both rear and mid, are direct coupled to the engine output. You might want to check if the tractors you are considering are configured similarly.
TMGT
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The B2601 (and the B7200 for that matter) are always turning the hst when the pto is operating.
The B2601 uses a hydrulic clutch to engage the pto but the hst is directly coupled with the engine and the pto gets its power from the back of the hst.
The B7200 is similar but the clutch is between the engine and the hst so the hst is stopped with the pto, however there is no way to run the pto without the hst turning.
Power loss in a static use is minimal and most likely wouldn't even be able to tell.
CalG
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When the HST is not asked to do "work" , i.e. moving the tractor against any load, it will not generate significant heat. The fact that the hydro is turning while the PTO is loaded has little bearing on "heat generation". THINK OF IT. a SWASH plate in a zero output position. Yes, there are fluid losses due to friction, but Nothing compared to doing useful WORK. (And by work, I refer to the engineering term.)
The clutch on the input is irrelevant.
TMGT
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No, but the mass is greater then a gear trans and it is still turning the charge pump which provides some small load, that's why I said it is a minimal loss.
I never implied it would build significant heat or there would be any problems with a hst in the OP's application.
As for the clutch/pto drive, I was just noting that there's no way to disengage the hst for pto use.
There's a reason that hst tractor are rated for slightly less hp at the pto then their gear drive counterparts.
There's a reason hst tractors have slightly less pto hp,
I never implied it would build significant heat or there would be any problems with a hst in the OP's application.
As for the clutch/pto drive, I was just noting that there's no way to disengage the hst for pto use.
There's a reason that hst tractor are rated for slightly less hp at the pto then their gear drive counterparts.
There's a reason hst tractors have slightly less pto hp,
CalG
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I think we are both trying to add information to the OP's concerns. For me, PTO work is NOT an hydrostatic efficiency issue. But there may be mechanisms that would refute that position.
Are there any "variable speed " hydrostatic drive PTOs" I've never heard of any.
TMGT
Elite Member
Yes we may have gone a bit more technical then necessary (a common problem of mine lol).
Bottom line from me is, yes an hst will use small amount of power and make a little more heat then their gear counterparts when using only the pto, but its not enough to worry about for the OP's application and either one will work just fine.
Although the B2601 isn't offered in a gear comfiguration so it might be a moot point.
