PTO speed

[thechknhwk]

I have an implement that states it needs to run at 305-350 PTO speed, but I'm not sure how to figure it out.  I have the 540 mark on my tach, so can I use a straight ratio to figure the appropriate engine RPM's to achieve the desired PTO speed?

For example

2100rpm = 540pto

2100/540 = 3.88 RPM's per PTO rpm, so 325*3.88 = 1264 RPM's.

The manual does say to run between 1000-1300 RPM's, but it also says exceeding the recommended PTO speed can damange the implement.

Any insight is welcome; I did search the interwebs for a conversion table but was unsuccessful.  The tractor is a Kubota L3800.

[Magicman]

Google "handheld tach".  Once you get it set for the proper PTO rpm's, you will know the proper engine speed.  That may be a solution.

[fishpharmer]

thechknhwk, you have already deciphered the solution.  Your calculation for engine rpm to pto rpm is correct.  It also equals the manuals recommended engine rpm.

What type of implement is it, I am curious?

[thechknhwk]

I may show & tell after I figure it out.  I'm sure you'll see a picture pop up sooner or later.  It's not anything super special, but I try not to be a show off.  Unless maybe it's my barn :D

[John Mc]

You've got it right, it's just a linear relationship. The easy way to think of it is what percent of the rated 540rpm PTO speed is your desired speed, then take that same percent of the 540PTO engine speed to get your PTO where you want it. (if you want half rated PTO speed, run your engine at half the 540PTO RPMs)

In this case 325/540 = 60.2%
60.2% of 2100 = 1264 RPM

[gspren]

  The only thing I'll add is that your rated PTO horsepower is at 540 so when you drop to a lower RPM you also lower your available HP, that may or may not be a problem depending on your "secret" implement.

[thechknhwk]

Thanks all

[Magicman]

Snow Cone Machines do not need much horse power.