Is 50 HP really 50 HP?

[Retiredguy2]

Hate the big wheels myself. Like the 20" crap on 1/2 tons All for looks and show.

The trend to 16's and 17's on 3/4 and 1-ton trucks though I think alot has to do with clearing bigger breaks to stop the heavier loads they are rated to tow.

Agree with you 100% about the 20" crap on half tons...my '08 GMC 2500 stops just fine with it's OEM 16" rims and the brakes that fit under them. 20" tires ride like (bleep) wear no better than smaller rim tires do, and cost a lot more. Another thing that baffles me is why automakers are trying to save weight so they don't include a spare tire on most cars now, but they can install huge tires and rims that add weight...all in the name of looks. Seems backwards to me.

 

[SPYDERLK]

Of course tit is true that a shop vac motor can produce 5 (whatever HP)

It can, but never will as the impeller does not load it that much.

If you hook a shop vac motor to a 50 Amp 120V fused supply and connect it to a dynamometer and then load the motor to its break down torque, it will make lots of hp.
For a few seconds anyway, till the windings cook and it burns down your shop.

The electric motor will produce 2 to 2-1/2 times its continuous duty power rating.

Continuous duty power rating might be 1-1/2 to at best 1-3/4 hp, as that is all you can ever get out of a 15 A 115 outlet.

1 hp = 746 watts, x Motor eff. (Use 90%)

These are universal series wound motors. Their HP remains about constant as they lug down; torque gain offsetting RPM loss. The current goes up and they burn up shortly tho so lugging them is very bad and, worse, futile in terms of power. ... OTOH, an AC induction motor runs at constant near synchronous speed way into overload and will put out double its rated HP for awhile. The latter is what youve described.

 

[mike69440]

HP is HP. Don't matter if it is gas, diesel, steam, electric, etc. Work done in a given time will be the same, if HP is the same.

As to the question, in today's soceity and with small engine makers just getting sued, and the fact that anyone can dyno their tractor, I don't think the MFGs are gonna lie about the numbers.

"I don't think the MFGs are gonna lie about the numbers"
It is very nice to trust.

Reagan said "Trust but Verify"

"HP is HP."
Very True

"Don't matter if it is gas, diesel, steam, electric, etc."
So wrong, I wil not bother to try to explain.

"Work done in a given time will be the same, if HP is the same."
Another true statement.

 

[mike69440]

These are universal series wound motors. Their HP remains about constant as they lug down; torque gain offsetting RPM loss. The current goes up and they burn up shortly tho so lugging them is very bad and, worse, futile in terms of power. ... OTOH, an AC induction motor runs at constant near synchronous speed way into overload and will put out double its rated HP for awhile. The latter is what youve described.

OK I will admit that I know little about small series wound AC motors, do they behave Like small DC motors?

Then it is impossible that a shop vac can produce more than 1500- 1800 wattts of power.

 

[Texasmark]

Who could blame one for believing nothing anymore. I once saw a shop Vac with 5 (or was it 6) HP sticker. It had 110 volt 15 amp plug. You can figure about 737 watts per horsepower. You can get about 1700 watts from a normal outlet so how did they get 5 or 6 hp? Maybe it had a free energy collection system.

Anything to fool and fleece the consumer.

Notice the fine print in advertising: "Peak" HP. Induction motors generate counter ElectroMotive Force (EMF) when running which keeps the current in check from the initial inrush surge that gets the motor turning. In a time lapse environment where you are monitoring voltage across the windings and winding current (dual trace oscilloscope presentation preferred), when you "lock the rotor" meaning you grab the shaft upon which the rotor is mounted and stop it, the counter EMF will disappear and the current limit that existed while running also disappears allowing the current to surge being limited by nothing more than the dc ohmic resistance of the coils (and the capabilities of your power company and supply system) and the applied voltage.

There is a period of a few milliseconds or thereabouts with different motors, where the voltage is still up at the normal 120 line (hasn't started to drop yet do to the high current on the line) and the current starts it's ramp with the locked rotor. Solving for max volts x amps at that point gets you the peak wattage hence the peak calculated hp rating. It's legal just gotta read the fine print. Actually what you want is the rated "Line Running Amps" and efficiency and rated voltage and power factor to truly get the wattage and then apply your 746 watts per hp and you have your real hp. Usually the name plate on the motor has this information.

And yes it's a fleece job just like $29.99.99.99 is not really 30 bucks, it's 29.99.99.99 and if you don't believe it ask the salesman. He will tell you just that. What's funny about this fleece, when they sell they use this process. But when they have a sale, bla bla bla savings of $30 on this unit bla bla bla, not you can save 49.99.99.99 on this item. But in all due respect, I got another HF catalog a couple of days ago and believe it or not, it said save $29.99.99.99 on a particular item and that methodology was used throughout that circular. My my.

 

[MHarryE]

I began my engineering career at Allus-Chalmers, as part of graduate training watching tractors being prepared for Nebraska tests. There was no "hot ridding". In fact the engines were de tuned to be in the low end of expected production and the rest of the power train was carefully built using carefully selected components. Experiencing a major failure during a Nebraska test can be devastating - the word spreads like wildfire. An example tractor from A-C is the 190XT. Test result competitive with its peers, the IHC 806 and JD 4020; however, A-C dealers will tell you it is rare to dyno a tractor that doesn't significantly exceed the Nebraska test result.

I found my permanent position at Allis-Chalmer's Combine Division but continued to hear from headquarters how production 190XTs scattered transmission and final drive parts all over the farm belt. We at combines felt the pain because R&D resources were limited by need to fix the 190XT. In addition a lot of money went to warranty. I believe it was the 190XT Series 3 before it became a solid machine but that was quickly replaced by the 7000 series which would have come sooner except for resources used redesigning the 190XT.

I don't think other companies do much different. Farmers pay more attention to torque backup and fuel economy. Our JD 7720 is now getting old, about 9 years, but is still an excellent performer. Fuel economy is excellent just like in the Nebraska test. I believe the tractor was published as a 130 PTO tractor but the Nebraska test shows 141 HP at max rated power, 145 HP at rated PTO speed, and an astounding 160 HP at max tested power (450 rpm below max rated). Horsepower is 2PiNT/33,000 where API is Pi, N is engine speed, and T is torque. Following the formula, the torque needed to increase 40% from rated power 2100 rpm to peak torque 1650 rpm. An operator can feel it - I have never needed to shift down because the engine was bogging. It just bears down and pulls through the tough spots. However this tractor is the lowest output middle of a trio of same gear train, different engine power ratings. Dealers tell us not to trade - this is one of the most reliable tractors JD has built. Selecting this tractor - torque backup was very important. Engine power - enough to handle current equipment. Fuel economy - was a bonus, not a real driver for us but impressive when we compared it to the tractor it replaced.

 

[Texasmark]

I began my engineering career at Allus-Chalmers, as part of graduate training watching tractors being prepared for Nebraska tests. There was no "hot ridding". In fact the engines were de tuned to be in the low end of expected production and the rest of the power train was carefully built using carefully selected components. Experiencing a major failure during a Nebraska test can be devastating - the word spreads like wildfire. An example tractor from A-C is the 190XT. Test result competitive with its peers, the IHC 806 and JD 4020; however, A-C dealers will tell you it is rare to dyno a tractor that doesn't significantly exceed the Nebraska test result.

I found my permanent position at Allis-Chalmer's Combine Division but continued to hear from headquarters how production 190XTs scattered transmission and final drive parts all over the farm belt. We at combines felt the pain because R&D resources were limited by need to fix the 190XT. In addition a lot of money went to warranty. I believe it was the 190XT Series 3 before it became a solid machine but that was quickly replaced by the 7000 series which would have come sooner except for resources used redesigning the 190XT.

I don't think other companies do much different. Farmers pay more attention to torque backup and fuel economy. Our JD 7720 is now getting old, about 9 years, but is still an excellent performer. Fuel economy is excellent just like in the Nebraska test. I believe the tractor was published as a 130 PTO tractor but the Nebraska test shows 141 HP at max rated power, 145 HP at rated PTO speed, and an astounding 160 HP at max tested power (450 rpm below max rated). Horsepower is 2PiNT/33,000 where API is Pi, N is engine speed, and T is torque. Following the formula, the torque needed to increase 40% from rated power 2100 rpm to peak torque 1650 rpm. An operator can feel it - I have never needed to shift down because the engine was bogging. It just bears down and pulls through the tough spots. However this tractor is the lowest output middle of a trio of same gear train, different engine power ratings. Dealers tell us not to trade - this is one of the most reliable tractors JD has built. Selecting this tractor - torque backup was very important. Engine power - enough to handle current equipment. Fuel economy - was a bonus, not a real driver for us but impressive when we compared it to the tractor it replaced.

Harry, nice post. If I read you right the torque curve peaks at 1650 and the PTO rpm is 2100. 40% is a goodly amount and yes I, for one can understand feeling it.

I had a 40 year old MF 35 with the 3 cyl Perkins. Peak was at 1000 and PTO 1600-1800, don't remember exactly. But the serv man did talk about using that rising peak in lugging situations. I almost had an accident one day and the tractor was put into a lugging situation whereby it just kept chugging. As you said, you can feel it and it's quite impressive. I'd still have it today, some 10 years later if whomever replaced the clutch, or the original design, don't know which, would have installed softer clutch springs. My left knee couldn't take the pressure depressing the pedal due to a previous non-related injury......getting into and out of sedan model cars!!!!!!

 

[LD1]

"Don't matter if it is gas, diesel, steam, electric, etc."

If you have 4 engines that all make 10HP, a gas, a diesel, a steam, and an electric, They are all capable of doing the exact same amount of work in the exact same amount of time.

 

[buickanddeere]

Telling me that 50HP is different from an AC induction motor, Series motors, four stroke diesel, two stroke diesel, four stroke gas, two stroke gas, steam turbine , reciprocating steam, gas turbine , water turbine or oxen on a treadmill?

 

[LD1]

Im not. I am saying HP is HP.

It dont matter weather the 50HP comes from actual horses, the power grid, crude, or a fire. They are all capable of the exact same thing. Thats 27,500 ft-lbs per second.