PTO RPM MULTIPLIER
- Thread starter sardillim
- Start date
Companies like Pronovost Snow Blowers sell these gearboxes for extra large tractors so that their 1,000 rpm pto's can be lowered to 540 rpm.
If you explained your need in some detail perhaps more useful advice can be provided.
If you are trying to make your own "Economical" pto for your tractor, for smaller machines it typically does not work because you are needing more torque than is available on the engine torque curve at lower engine rpm;s.
Dave
If you explained your need in some detail perhaps more useful advice can be provided.
If you are trying to make your own "Economical" pto for your tractor, for smaller machines it typically does not work because you are needing more torque than is available on the engine torque curve at lower engine rpm;s.
Dave
North Idaho Wolfman
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Yea what are you trying to run with it?
You lose a ton of HP with a multiplier, most of the time making it really unusable, and on a B2650 your not going to have much left.
You lose a ton of HP with a multiplier, most of the time making it really unusable, and on a B2650 your not going to have much left.
Thanks for the info. So I was without power for 5 days when Isaias came through a couple of weeks ago, I have a pto generator for the basics to keep the house going. My issue is that the tractor is running at around 2350 rpm to run the generator. I feel like the tractor can run the generator at a lower rpm. so my thought was to overdrive the pto to cut the engine speed.
Before making such decisions you need to educate yourself about Torque Curves publish by manufacturers for each engine.
Some focus on horsepower numbers but the real "hands on," test is measuring the engine's torque at all possible rpm's.
Horsepower is never measured but rather calculated from the torque and rpm.
The following is from something I wrote at another time:
For satisfactory generator operation, the engine needs to be running on the downward slope of its torque curve so that if it slows slightly under load the available torque is increasing.
Starting to try and run the engine slower means you may be at a point on its torque curve where the torque falls off as rpm's decrease which can lead to a sudden stall.
I apologize for resorting to technical jargon to make a point but it is critical in generator operations.
The torque curve shows a downward slope as it goes from 2,800 to 3,600 rpm.
If you have the engine rpm's in that range and the load on the generator increases as the engine starts to slow down from its 3,600 rpm needed to produce 62 cycle AC, the torque output of the engine increases so it accepts the extra load without any fuss.
If you think it is a good idea to slow the engine down and use pulley's and V belts to turn the generator head at 3,600 rpm, you are now operating on a place on the engine torque curve where a slight lowering of engine rpm produces less torque and this situation quickly deteriorates into the engine stalling.
The following torque curve is not for your engine but all engines have similar curves.
The tractor designers calculate gear ratios and study torque curves in order to have the pto 540 rpm occur at point #3 on the curve below.
What you are wanting to do is to run your engine at #1 on the torque curve. This is possible on large tractors with far more power available than the application (generator) needs. Tractors are now available with an E pto option to accomplish what you wish to do.
However, in your size of tractor it is a wish that is likely impractical.
Your tractor's engine was designed to run at the pto rpm.
Dave
The B7200 has a two speed PTO. I use the high shaft speed selection at reduced engine rpms quite often while shredding garden and yard (forest) waste to make composte.
It works fine. It really boils down to how much electric ouput the poster requires.
During a power out, I can do what I need to do in the house on a 5 HP portable generator.
If I had a tractor driven unit, I would certainly use the high speed PTO option.
I would also be sure to monitor the output frequency to make sure the engine didn't drop off excessively under load.
Two of my tractors have two speed PTO's they are very useful. The third tractor has a single 540, but full engine power comes at 1000 rpm, so it sounds relaxed even when at peak.
It works fine. It really boils down to how much electric ouput the poster requires.
During a power out, I can do what I need to do in the house on a 5 HP portable generator.
If I had a tractor driven unit, I would certainly use the high speed PTO option.
I would also be sure to monitor the output frequency to make sure the engine didn't drop off excessively under load.
Two of my tractors have two speed PTO's they are very useful. The third tractor has a single 540, but full engine power comes at 1000 rpm, so it sounds relaxed even when at peak.
GreensvilleJay
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BX23-S,57 A-C D-14,58 A-C D-14, 57 A-C D-14,tiller,cults,Millcreek 25G spreader,
hmm.. 'PTO generator' is a kinda vague description....
I'd need to know the power rating of it, how many KW it can produce, as well as what you need it to power in the house.
Let's say the genny is good for 10KW an you only need 1KW for the house. We'll say the tractor can put the equal of 2.4KW to the PTO. 'number wise' it is possible that it 'might' work. A LOT actually depends upon the real numbers....
I'd need to know the power rating of it, how many KW it can produce, as well as what you need it to power in the house.
Let's say the genny is good for 10KW an you only need 1KW for the house. We'll say the tractor can put the equal of 2.4KW to the PTO. 'number wise' it is possible that it 'might' work. A LOT actually depends upon the real numbers....
I made the same decision but one reason was when we loose power it seldom is cold weather and if so we use our gas logs. But at same time I realize no more often than I would really use one for say four days and we have been hit often the last few years with hurricanes, that would be about 100 hours and on my tractors a 100 hours would not harm them...they have age not hours.
We had a big ice storm in 1998. No power for weeks and I had to work each day thus leaving my family at the end of a 3,500 watt Honda.
I bought a 22 KW Generac to run on propane. 22 KW because it was the only size to come with an aluminum enclosure.
Since buying the Generac, the power has only been off twice, once for about 6 hours when the farmer renting my land pulled down the local utility poles with some fold up big implement.
It is a relief to have the Generac. It is nice not to have to do anything when the power goes off. Nice not having to keep fresh fuel for a gas generator.
We live where it gets very cold so if the power goes out, then there would be the worry of the tractor starting to drive a pto generator.
Now in my 70's, the decisions are different than when I was 30.
Dave