PTO snowblower running 1000 rpm?

[msjanket]

I've got a Holder A50/411 putting out around 50Hp at the PTO. Will the tractor handle an 86" blower or is this grossly underpowered? I don't have an HST on the tractor.

The big question is this. I want to run the blower in the front of the tractor where I have a PTO and 1000 rpm PTO. Is this PTO speed simply excessive? Will it damage the gearbox at this speed?

 

[tractchores]

Some blowers are made for that rpm, others offer a gear box that steps it down. Look at your specific blower. I think there is way more than enough hp to run a blower that size. I run a 60" on a bit over 20 hp pto and it has more than enough power.

 

[pmsmechanic]

I restored an IHC model 80 snow blower. The pto had been converted to 1000 rpm. I left it like that and the gearbox has had no issues.

Friends of mine in Manitoba have a Universal tractor. I don't know the model but there is a provision in the transmission to run the 540 pto at 1000 rpm. They regularly run their 540 rpm snow blower at 1000 rpm. Again no problems other than the snow blower now throws snow quite a bit further.

There is much wisdom on this forum saying that the gearboxes are designed to run at 540 rpm and that they should stay there. Then there are those who run their gearboxes at 1000 rpm and realize that even though the gearboxes are designed to run at 540 they actually perform quite well at 1000 rpm. The objective is to move snow further away and this easy modification does that quite nicely.

I am not an engineer but I do know that if you double the speed of a shaft you can transmit 4 times the horse power through that same shaft. That's why as tractor horse power increased in the early 60's, 1000 rpm pto's came into existence. I'm thinking then, that it's probably easier on a gearbox to run it at 1000 rpm rather than 540, all else being equal. The only question that comes to mind is oil sheer destroying lubrication because of the faster speeds involved. Again that's probably not an issue as there are many gear boxes that turn faster than 1000 rpm.

 

[doxford jim]

There is also the fact that the snow blower can be run at any speed from 0 through to 1000 rpm. Just vary the engine rpm will also vary the PTO output speed. Granted the peak HP won't be there but it is possible to run the snow blower to suit the immediate needs. I have two PTO speeds 540 and 720 and I use both depending on the circumstances. As long as the gear box oil levels are maintained, there should not be a problem (generally speaking of course).

 

[PILOON]

Standard rear blowers are generally designed for 500 RPM.
Most fronts are geared for 1000 rpm's or (engine RPM) and also tend to turn the other way.
That being said as a general rule a rear blower mounted up front wants a reverser as well as a speed change.
All in all adapting rear to front is generally not economical. (requires gears and or chains & sprockets + a box etc)

All that being said I run my rear at 700+ rpm (3 speed pto) without any issues but at 1000 it vibrates excessively.

 

[tractchores]

I accidentallly ran my rear blower at 960 RPM today for a while (shifted the lever forward instead of backward). It sounded like an airplane taking off an really threw the snow. It also vibrated a lot. I would be worried about the shockload breaking something if you hit something at a higher speed (may not sheer the sheer pins as intended before doing serious damage). In my case I also noticed the fan blades are not that well balanced and there was a lot of vibration at the higher speed. It would be nice to have the option to run at higher speed with smaller snow amounts it really throws it better than the 540 RPM

 

[pmsmechanic]

When I rebuilt that IHC 80 I had to build a new fan. The old one was in pieces and no longer available new. I started off with a square piece of 3/8th's flat and had a hole machined into the center. I welded a browning hub in and then cut four pieces of 6" channel iron to the same length and carefully welded them onto the square 3/8th's flat. I followed the pattern of the old fan and welded bracing to hold the fan together. I used equal amounts of welding rod on every weld, to the point of weighing the welding rods. I had left the fan open enough in the center to use a tire machine to balance the fan. I took it to the tire shop to balance it and was only one ounce out. After an ounce of weight was welded on the fan was in balance and no problems at 1000 rpm.

So if the center of your fan is open enough to take it to a tire shop for balancing that's a cheap easy way to do it.

 

[Rustyiron]

Good idea!

 

[Mace Canute]

I restored an IHC model 80 snow blower. The pto had been converted to 1000 rpm. I left it like that and the gearbox has had no issues.

Friends of mine in Manitoba have a Universal tractor. I don't know the model but there is a provision in the transmission to run the 540 pto at 1000 rpm. They regularly run their 540 rpm snow blower at 1000 rpm. Again no problems other than the snow blower now throws snow quite a bit further.

There is much wisdom on this forum saying that the gearboxes are designed to run at 540 rpm and that they should stay there. Then there are those who run their gearboxes at 1000 rpm and realize that even though the gearboxes are designed to run at 540 they actually perform quite well at 1000 rpm. The objective is to move snow further away and this easy modification does that quite nicely.

I am not an engineer but I do know that if you double the speed of a shaft you can transmit 4 times the horse power through that same shaft. That's why as tractor horse power increased in the early 60's, 1000 rpm pto's came into existence. I'm thinking then, that it's probably easier on a gearbox to run it at 1000 rpm rather than 540, all else being equal. The only question that comes to mind is oil sheer destroying lubrication because of the faster speeds involved. Again that's probably not an issue as there are many gear boxes that turn faster than 1000 rpm.

Yep, you're quite correct. As you say, there are many gear boxes that turn faster than 1000 rpm and never have any issues whatsoever. Lubrication is going to be much more relevant than the speed it spins at. I wonder if the people who fear the higher rpm will destroy the gearbox ever change out the oil in their gearboxes or put in the cheapest stuff off the shelf that they can find when they do?

 

[oldnslo]

Yep, you're quite correct. As you say, there are many gear boxes that turn faster than 1000 rpm and never have any issues whatsoever. Lubrication is going to be much more relevant than the speed it spins at. I wonder if the people who fear the higher rpm will destroy the gearbox ever change out the oil in their gearboxes or put in the cheapest stuff off the shelf that they can find when they do?

Only other concern would or could be increased heating of the oil due to the increased splashing. On a snow blower this probably is not a concern, on a bush hog being run in 100 degree temps could be a concern.