hp ratings ?

[smilingreen]

When a manufacturer builds a product, he rates the max horsepower for the PTO as a guaranteed horsepower. The product itself will probably withstand a lot more than that, but the precentage of break damage goes up. When you buy a strap rated at 3000 pounds, the manufacturer guantees that the strap will move 3000 pounds, but it is usually tested at much higher weight, usually 100% more, maybe 6000 pounds before the strap will break.
A shear pin is usually put in a drive train where it does not have a slip clutch. The pin is a expendable or wear item that protects the equipment gear box and tractor PTO from being damaged by sudden shocks in the drive train. That is why they make grade #2 bolts, also. It is a protection device installed in the system. It is a expendable item. I would rather replace a $.40 bolt and nut than replace a $400.00 gear box, anyday.

 

[jimg]

Another HP question: Ive seen spec sheets w/ the tractors engine net & gross hp and PTO hp ratings. I dont undestand why the engine hp is given in terms of 2 ratings (net and gross).

 

[JDgreen227]

I am not positive, but I think the gross hp ratings would be the power developed with the engine not installed in the tractor and not powering accessories like alternator, hydraulic pump, etc. while the net hp rating applies to the installed engine running the accessories. You have a good question that I can't really answer, what IS the purpose of a gross hp. rating? For comparison purposes? Anybody else know that one?

 

[JDgreen227]

You must have some really big gophers, I have hit huge anthills on my property that were a foot high and a foot across with my bush hog and still have not broken a shear pin yet. YET.

 

[Egon]

(net and gross).

This is sorta like your income. What you think you make and whats left over after everyone takes thier share.

Egon

 

[JDgreen227]

Let's see now, gross income is what you earn, net income is what you have after everyone takes their share, that makes sense to me.

So after my wife gets HER cut of what's left, that means I end up with pto income...... right ? /forums/images/graemlins/confused.gif

 

[jimg]

OK, but why would you spec both?

 

[nomad]

</font><font color="blue" class="small">( Another HP question: Ive seen spec sheets w/ the tractors engine net & gross hp and PTO hp ratings. I dont undestand why the engine hp is given in terms of 2 ratings (net and gross). )</font>

I don't know what are meant by gross and net hp /forums/images/graemlins/smirk.gif Maybe, gross hp is hp including the package? /forums/images/graemlins/cool.gif

Seriously. Maybe, we should ask another (related) question.
When it's said "Engine HP" exactly at what point of the engine is that "Engine HP" measured and given in the tractor manual? Is it at the crank? At the tires? In the combustion chamber? Where? If we answer this, we can answer net and gross HPs.

Ps: you know the point of pto HP and can measure that HP yourself easily - But how do you measure Engine HP? (assume you lost the manual or your tractor is old or you don't believe tractor mfg.)

 

[jimg]

Yes, exactly. Its rather like electric motor hp ratings on power tools. Certain mfgs inflate motor hp rating to the point where its meaningless.

Its completely unclear (to me) why an end user would care what the diff between gross and net is. I might want to know net and certainly PTO but gross would only tell me how much auxillary systems are sucking off. Only a very few of those systems could the end user effect (like turning off the AC). Im sure Im missing something obvious here...so humor me...OK?

 

[Soundguy]

I used to have lots of them on the property.. but after I got rid of the cactus on the property... they all left. Sometimes the dirt mounds will be 1' tall.. and a cople feet across. A single mount doesn't pop it... a day of mowing would though.

Annoying as it is.. I'm mowing with the same shear bolt from last year ( didn't break it ).. but it is actually half way cut... so I can't back it out and change it.. I just have to wait till it pops to chage it... oh well..

Soundguy

Hey to add to that net / gross discussion.. how about rated HP