Wouldn't This Be Overunity?

Sounds very much like a case of bad marketing.

Do you have a link to the product, I wouldn't mind having a look at the manual for clarification.

all the manufacturers say it they all boast 6.5 or 5.5 hp 250 mph windspeed out of blower att 440cubic feet per minute out of a 2 " exhaust port google any electric leaf blower black ndecker shop vac any of them use this hp rating

Here's one that claims ¾hp, 550W. That sounds about right to me.

Maybe I missed it, but I can't find any mention of hp on the Black & Decker site.

Can you give a link to an example?

Nothing on the Husqvarna website either (perhaps it is a selection of American sites).

Do you have a link?

Actually, it's a case of good marketing. Manufacturers inflate their HP claims to hoodwink the public that their product is better, more powerful than that of the competitors product. Most non-technical people will believe it.

Sounds like mis-labelling or bad marketing...6.5 HP would be extreme overkill for a residential-use electric leaf blower!

It must be mis-labelling or bad marketing...6.5 HP would be mini horse power

The concept involved here is referred to as "developed horsepower". The rating we typically assign to a motor's HP or kW is based on a steady state load at slip speed. But technically, HP is a calculated relationship between speed and torque, and torque has calculable relationships to current and voltage. Power Factor is also as important as the other two values because it represents a more direct relationship to slip. So how does this fit together?

When they say "6.5HP", there is probably an asterisk somewhere that says "developed HP". So when you look at the MAXIMUM slip the motor can tolerate without stalling, then measure the current draw and calculate the torque at that point, determine the speed at that instant and calculate HP, it will probably come out to 6.5. That motor cannot SUSTAIN that for any length of time, so the value is essentially meaningless, but that is how they get away with using that in marketing.

GA to you, best answer thus far. This crap/bollocks/B.S. of "peak horsepower" as the slimy marketing types like to call it, is where you run it up to its maximum RPM with no load, then stall it with a mechanical brake very quickly and measure the torque peak or locked rotor current. In essence they are multiplying the peak values of two curves that are inversely proportional. True horsepower of course as other posters have indicated is Vrms * Irms / 746 is a lot closer to the truth minus the winding losses, core losses, friction, etc. And why do I care how much horsepower my ShopVac generates? It either sucks or it doesn't.

It seams to me the case of two different manufacturer one who manufactured motor whereas another just fixed blower on it,

6.5 Hp may be the rated output of motor, but here in this case blower is not large enough to load motor up to rating. In another words impeller fixed on motor is underrated.

There are loads of devices with outrageous power ratings that are no where near their actual real power outputs. Check out air compressors. I have seen some rated at o10 hp that run off a 240 volt 20 amp line and only produce an actual 9 CFM at around 100 PSI.

My industrial unit is 10 hp and knocks out an honest rated 45 CFM at 175 PSI! It can pump up a 200 gallon tank system in the same time my neighbors 6 hp rated one does its 40 gallon tank and his stops at 130 PSI!

Weed eaters, chainsaws, circular saws, drills, GM, Ford and Chrysler vehicles!

Advertised power is no where near the real power levels on much cheap public grade stuff.

It's bolox.

Have you ever seen horses trying to pick up leaves: they're just not very good at it.

Sorry, couldn't resist.

6 horses and a pony, chained to a turnstile that is, by virtue of pulleys and belts designed to increase the speed of the shaft, connected to a centrifugal blower, the intake of which is connected to a hose that is used to suck up the leaves. Not exactly portable, but technically possible.

But the issue the OP is questioning is, can 2 horses connected to this contraption, whipped until bloody, do the same amount of work as those 6 horses and a pony? The answer is, only until they die or break their harnesses and bolt!

6.5HP. If you think a horse is bad, HALF a horse is even worse (or is that 6 horses + a single horse that just cannot be bothered on the day to make an effort).

Or look at it this way;

Cutting a horse in half effectively kills it, making t non-contributing as a prime mover and in fact if it were connected, it actually adds to the mass. So the remaining 6 horses must now drag the dead 1/2 horse as (literally) dead weight and thus have the EFFECTIVE shaft power at the blower suction of 2 horses.

Unless, of course, the 1/2 horse is this breed...