PTO speeds

[DMB]

I have no doubt this has been discussed, but I'm still fairly new to the forum and I suppose I missed it so here's my concern: I've looked at tractors with 540 and 1000 rpm PTO speeds and some with only the 540 rpm speed. The 540 seems to be the standard. What is the 1000 speed for and would I be missing out on something by purchasing a unit with only the 540 speed? Thank You, DMB. /forums/images/graemlins/confused.gif

 

[Bird]

David, the 540 speed on the PTO is what I'd call the "standard" speed and most all implements, especially those that will work on the smaller tractors, are designed (proper gear ratios in the gearbox, etc.) for the 540 rpm PTO. However, some of the larger implements for the big tractors are designed for a PTO that turns at 1000 rpm. So that's the reason some tractors have both speeds built in. Now I certainly can't say if or when 1000 rpm implements might be available for the smaller tractors (possibly even now that I don't know about), but in my opinion, the 540 is all you need unless you're talking about tractors over at least 60 to 80 hp. Maybe someone else knows more about whether anything is available in the 1000 rpm for smaller tractors.

 

[frank_f15]

as BIRD said the 540 rpm pto is pretty much the standard. u don't mention which size tractor u are looking in to or its intened uses. might be helpful /forums/images/graemlins/laugh.gif

 

[leaddog]

I have a century 3045 and it has both 540 and 1000. All the century and bransons have the 2 speeds. I have found that the 1000speed comes in very handy as I can run an attachment at a lower engine speed and still have the attachment run at proper speed. One note of caution though, if you speed up the engine you will over speed alot of attachments. For instance I can run my brushhog at 1400 to 1500 engine rpm and have the brushhog running at proper speed but if I run the engine up to 2600 I have increased the cutting tip speed to twice the speed it was designed for and it becomes a VERY dangerus thing. So you need to use caution.
I have found that by running my snowblower at 1800 engine rpm that it works alot better and won't plug and blows the snow better.
leaddog

 

[leaddog]

One other advantage is that when you use the 1000rpm and lower your engine speed to run a 540 attachment you drop you tractor speed about in half. That is like going from 12 gears to 24 gears. It gives you alot more flexibity. That really comes in handy blowing snow and you are going though 4ft drifts
leaddog

 

[Soundguy]

In addition to the larger tractors sometimes having dual speed pto.. sometimes some asian tractors have 2 and 3 speed pto's.. for instance yanmar have 540 760 and 1000. I hear that there are implements like the oem yanmar tiller that need the extended speeds.

As you see.. the extended speeds are very limited for normal 20-30hp use.. etc.

Soundguy

 

[DMB]

Interesting answers from everyone. Frank did ask a pivotal question which I'll answer. I'll probably not exceed 30hp and the primary use of the PTO will be a finish mower, a post
hole digger and a rotary cutter will be the less common uses.
I never really thought of the 1000 RPM PTO selection with lower engine RPM option which has the same effect as a higher gear. It would seem in a lower hp tractor this might lead to bogging down more easily in some situations. I can also see where over speeding could occur with this usage. I appreciate the answers. TBN and it's helpful participants are a great resource. When you read the shiny tractor brochures there's at least a few things that aren't fully explained.
DMB

 

[rdbrumfield]

I know that the higher hp tractors have the 1000 rpm shaft, but it has a different spline than the standard 13/8 6 spline.
I like the 2 sp pto because when using hydraulic pumps for backhoes and wood splitters the tractor can be idled down. I don't use it for the mower or tiller. My dad borrowed my Yanmar and used the 1000 rpm and with the chattering of the tiller it knocked out the dampening springs of the main clutch. Remember, you almost double the shock load to the clutch when using the higher gear unless you are running something that is turning smoothly and don't have the risk of sudden stoppage you could risk some damage.

 

[keeney]

Some machines like my JD 4100 have a different speed on the mid/front PTO than they have on the back. The mid-mount mower and front snowblower use the higher speed mid-PTO. I would think that it would be 1000 RPM, but 2000 RPM also sticks in my head from somewhere. I would have to check the specs.

- Rick

 

[ZJ_HR]

There are all 3 PTO speeds on my tractor: 540, 540E (750) and 1000.
Most used speed on my tractor is 540E, because 540 rpm is achieved at 1660 rpm of engine (nominal engine speed is 2350 rpm). This is most convenient speed for mowers, rakes etc.
Ordinary 540 (achieved at 2080 rpm of engine)is just for tiller or power harrows.
Speed 1000 rpm (achieved at 2300 rpm of engine), we use occasionally, only for run circular saw or something like this. It is bought for use in future (who knows?).

Using 1000 for purpose of 540 is not recommendable (dangerous) because of several reasons:
1. Engine runs on too low speed (1240 rpm on my tractor) - weaker lubricating, weaker cooling, easy to overload engine.
2. Turbo doesn't "work" yet - bad combusting, black smoke, coal buildups on pistons.
3. Low engine speed is on rising part of torque curve (decreasing torque when load decrease engine speed)- very unstable for variable load, easy to stuck engine you "hit" something.
4. Hard to use hand throttle, because of engine speed "floating" (not so important).
5. EASY to overrun PTO attachment - VERY DANGEROUS!!! for your /forums/images/graemlins/shocked.gif, or yours tractor life /forums/images/graemlins/frown.gif , as somebody mentioned before.
6. Some more...but I don't know now... /forums/images/graemlins/grin.gif

Just a remind: on some tractors to engage 1000 rpm, you need to replace 6-splines PTO shaft with 21-splines, other can have shiftable 540/(540E)/1000 with 6 splines, like mine has.

My advice: if you can find 540 and 540E (750), this will be more convinient than 1000.
Almost standard setup on new tractors in Europe is 540/540E now, 1000 usually on demand.

Hope this helps,

ZJ

 

[rambler]

To answer the 'big tractor' questions: It becomes physiclly difficult to transmit more than 75-125 hp through an 1 3/8" shaft spinning at 540rpm. The iron wants to snap off (Case got up to the higher hp by using some very expensive rare-earth metals in their 540 shafts). So the 1000rpm pto with 21 splines became the standard for higher hp requirements.

On a lower hp tractor, if you've never had 1000 rpm, you won't miss it & I wouldn't let it stop me from buying a machine I liked.

As mentioned, some brand-specific implements are designed to use the special pto speeds available on those brands; and it can be useful or dangerous to use a 540 rpm machine on an idled back 1000rpm tractor. But if your implement is sized to your tractor, it will need most of the hp anyhow, so you'll need about full power in the first place.

--->Paul

 

[ZJ_HR]

Paul,
Sorry for misunderstanding. I was talking about tractors up to 50-80 HP. You're right, when power requirement is high, then is no question which speed range you need.
BTW, 21-splines PTO shaft I didn't ever see on tractor here, even on big (120-150HP engine) tractors.

I just want to say that 540E(750) is excellent choice for many uses, where 10% less power output is not a big loss.
MF 35, for example, has only 720 rpm speed, I mean no real 540, because it runs 540 at about 1700 rpm engine.

ZJ

 

[keeney]

Turns out that the Mid/Front PTO on my 4100 is 2100 RPM's. Since the tractor is only 18 Hp or something, I am pretty sure the higher RPM speed is not for high power output.

It must be because its easier and/or cheaper either in building the Mid PTO, or it makes the mower deck and/or front snow blower cheaper or easier to build somehow with less gearing-up or something.

Maybe its to be compatible with the 400 series garden tractors that share the same mid and front attachments?

- Rick

 

[rambler]

A faster spinning shaft can be smaller/ lighter, and use smaller gears to drive it to transmit the same hp. Most mid pto's run faster, your 2100rpm problably is _very_ close to the engine rpm..... Should be cheaper to make.

540 became an industry standard for rear pto under 65hp, & 1000rpm for over 100hp. Any other rotating shafts are up to the manufaturer. /forums/images/graemlins/wink.gif

--->Paul