When is a 540 PTO at 540? PTO primer needed

[Electron8]

I heard the expression "Engine at PTO speed". On my BX23, does the 540 RPM rear PTO speed happen at a certain engine RPM? Of course, this is where an accessory tachometer might be helpful. I have a Blizzard B54 snowthrower coming - I noticed some rear snowthrowers mention they have a gearbox to drive the impeller fan - I had assumed the fan on the B54 was driven directly by the PTO at that speed - wrong? It came up while trying to do feet-per-second calculations, which came to about 54 if the impeller is 1:1. Similarily, I read that the impeller turns on a BX2750 at 1000 RPM from the mid PTO - so is that geared down by the snowthrower from 2000+?

 

[Bob_Skurka]

PTO speed is based on engine speed. Implements are designed to function most efficiently at 540 PTO speed. If your tractor had a tachometer, there would typically be a mark on the face of the dial, you set the engine RPMs so that the needle is pointing at the mark and you have your PTO spinning at 540. If you don't have a tach, then I suggest you refer to your owners manual for their specific advice.

However, generally the tractor generates a 540 PTO speed when the engine is running about 90-to-95% of its full operating speed. I think it would be reasonable to run up to full operating RPMs on your engine, then back it down just a little bit, you'd very likely be just about right. You would want to run your mower deck and your snowblower at 540 PTO speed (if you have a mid-PTO it may well run at a different speed, however the engine speed would very likely need to be the same as if you were running 540). Don't worry, you won't over-rev the tractor, it has a governor on it, further, these little diesel engines are pretty much designed to run at those RPMs all day every day for years (typical life span is roughly 10,000 hours and most folks put less than 100 hours a year on their little tractors).

Running too slow and you may not get the fan speed on the blower up high enough to efficiently move snow out of the chute. Running too slow with the mower deck could lead to more tearing of the grass rather than cutting of the grass.

The only implement that I can think of off hand that is NOT typically recommended to run at PTO speed is a Post Hole Digger.

While your tractor probably doesn't have it, there are some 2 speed PTOs on some tractors that run either 540 or 1000. For small tractors, there are virtually no commonly available implements that run at any speed other than 540 here in the US. Farmers with large machines do utilize different PTO speeds than us folks with small & medium size tractors (Sub-CUTs and CUTs).

 

[notamustang]

I had the same quesiton with my BX2230 and since there is no tach its just gonna be hit or miss for me.

If you have a need to know rpm, I have seen people talk about a product called a tiny tach. Looks like its easy to install and I think they are about 75 bucks. Now I have not used one and will do some more research befroe I drop the money.

 

[Volfandt]

Not having a tach is about the only drawback I've encountered w/the BX23, so far. When I was shopping I brought this up w/two different Kubota dealers and both answered w/just about the same exact answer. The owners manual says similar too. What I was told is to run the BX23 WOT ( or very close to it) inorder to get 540 rpm's on the rear pto and 2500 rpm's on the mid pto.

The manual indicates the engine needs to be at 3068 rpm to make 540 at the rear and 3125 to make 2500 at the mid.

I haven't run any pto implements yet and won't run the engine anywhere near WOT until I've hit 50 hrs. From what I've read here, most don't run their engines at WOT even after breakin as they feel the mower does a good job at lower rpm.

I used to work an old 1948 Ferguson TE20 pretty hard bush hogg'n 3 acres every other week and it didn't have a tach either. I ran the engine at the speed were it's sound and performance "felt" the best, which was usually never at WOT unless I got into the tall stuff or when plowing deeper....

I believe I'll be useing the same gauge when working the BX23 also.

As for what speed to run a snow blower, all I can add to that is, "what is snow?" /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif Haven't seen any all winter....
(course ole man winter ain't left yet)..... And if he does blow some my way, my ole 856 Wheelhorse w/snowplow/graderblade will get alittle exercise then /forums/images/graemlins/grin.gif
Volfandt

 

[frank_f15]

without a tach, do as BOB SAID run at full throttle then back off a bit.

 

[NY_Yankees_Fan]

In this post you will find a table with RPM and PTO info. web page
I always wondered how fast my PTOs were spinning. Now that I have my Tiny Tach I won't have to guess. Below is an RPM table that I have posted in my garage. The formating isn't too good. I will try to attach a text file with the same info.

Eng
RPM Rear Mid
1200 211 960
1250 220 1000
1300 229 1040
1350 238 1080
1400 246 1120
1450 255 1160
1500 264 1200
1550 273 1240
1600 282 1280
1650 290 1320
1700 299 1360
1750 308 1400
1800 317 1440
1850 326 1480
1900 335 1520
1950 343 1560
2000 352 1600
2050 361 1640
2100 370 1680
2150 379 1720
2200 387 1760
2250 396 1800
2300 405 1840
2350 414 1880
2400 423 1920
2450 431 1960
2500 440 2000
2550 449 2040
2600 458 2080
2650 467 2120
2700 475 2160
2750 484 2200
2800 493 2240
2850 502 2280
2900 511 2320
2950 519 2360
3000 528 2400
3050 537 2440
3100 546 2480
3150 555 2520
3200 563 2560

 

[btolle]

I have a tach on my B7510 and it indcates that what others have said is correct, go to full throttle and then back off just a bit until you hear the RPM's drop just a little. Full throttle on my B7510 is about 200 engine RPM's faster than the 540 mark on the tach for the PTO.

Snowblowers may be more critical, but bush hogging I can run mine a couple of hundred engine RPM's lower than the tach indicates as 540 PTO RPM and it cuts just as well.

Bill Tolle