Slip Clutch Sizing

[Tahoe BX23]

Did you know that slip clutches need to be sized to PTO hp?

I bought a Weasler slip clutch at Tractor Supply as an alternate to sheer bolts, put it on my Brush Hog and resized my PTO shaft. When I tested it out nothing slipped. Since it was brand new I looked for the manual online on how to properly adjust. Did not find one so I called Weasler and learned three things: 1) ther is not a manual and 2) the slip clutch I bought requires 8K in/lbs and 3) a 17 hp PTO is only capable of 2K in/lbs and the unit I bought can not be adjusted to 2K in/lbs.

I am surprised that manufactures and dealers do not post a sizing guideline... do others agree?

 

[mickeyd]

Welcome to OTT from Alabama. I don't know about standalone slip clutches, but when reading the specs of tiller manufactures, they always list the required minimum and maximum HP for each size tiller/clutch.

 

[Tahoe BX23]

So here is the rub, my Brush Hog manual states that I have the correct HP for the rotary mower and even suggests you can add a slip clutch. But the slip clutch separately does not spec hp in any literature only in/ lbs and when you talk to that mfg they say no.

 

[Russell King]

The slip clutch people have no way to control what RPM will be applied to the slip clutch so can not talk in HP. They could give you HP ratings at 540 RPM but probably don't want to get sued.

Please ensure you have your units straight first since you have used inch/pound for torque when it should be pound * inch which I think is what you mean for the 8000 rating you use. Please know if they are in inches or in feet when they rate the torque also.

You can calculate the HP at a given RPM using known torque values using something like this website:
http://www.wentec.com/unipower/calculators/power_torque.asp

At 540 RPM the 8000 pound inch would give you 68.5 HP
At 1000 RPM the 8000 pound inch of torque would result in 126.9 HP

 

[OldeEnglish]

So a slip clutch is not adjustable? Im curious because I'll be picking up an old used/abused bush hog that happens to have a slip clutch and I know nothing about it. I wasn't looking for a hog with a SC but came across this one for cheap and I assumed they could be adjusted for different HP....