Horsepower Small Electric Motors and Gasoline Engines

Here is my attempt to measure the horsepower output of two fractional horsepower electric motors and small gasoline engine. I'm testing a very old electric motor to see if it's trash or not. At the same time comparing the measured horsepower with the rated horsepower of electric motors and gasoline engines to prove or disprove the assumption that an electric motor will do the same work as a gasoline engine with two or three times the rated horsepower. The results are at least interesting if not surprising.

[Z-Ack]

I appreciate the hunger for knowledge and get rather frustrated at most of the professors that have some age on them. One would think a well seasoned professor would have the experience to give out some of the tricks and trade secrets that the hungry crave when getting into a field. Seems more and more i see pofessors that are tired and have just developed a negative view about things focusing more on acedemic behavior rather than the feel of the need to give out and share their knowledge with those wanting to gain it. Aside the fact of the statistical bs where 1 in whatever students will be a negative nancy push off, it lifts my spirit every time i see that enthusiasm even if one doesnt comprehend. With youtube, there is no knowledge of comprehension, only faith that it may help or enlighten another. That my friend is what defines a professor as a mentor. Making things legible is an art and defines a professor as a teacher. You sir are both, thank you for your years of gratuity and service to the people. Godbless.

[sayedsamoray]

I like the idea that you present sir it was so helpful

[EETechs]

AC induction motors, like the one you are using, have what is called breakdown torque. This is the peak torque the AC motor will produce before the torque sharply falls off to the point that the motor stalls. This is not like a DC motor that has max torque at zero RPM's. 

So with the breakdown torque of the AC motor, you can get much more horsepower out of the motor because as you overload the motor you gain torque, but you also have minimal speed loss so horsepower increases as well (so does current draw to satisfy the power input increase for the mechanical power output increase).

For gas engines, torque does not increase as you overload them. Thus, gas engines lose speed and torque, therefore the horsepower will start to decrease as you overload gas engines.

I made a video explaining this here: /watch?v=eoIRsqfLH5Q

[bobham]

Hi:
Interesting experiment but it appeared to me that the scale you were using had pound graduations on the outside of the ring and kilogram graduations on the inside of the ring.  You appeared to be taking your numbers from the inner ring (kilograms) rather than the outer ring (pounds) which would make a considerable difference in the calculations, wouldn't it?

Bob

[logmegadeth]

Interesting video. Your setup seems similar to that of a deProney brake.

[maximumiq]

I think you have to consider the gasoline engine revs when measuring its power. The power curve is quite step on both sides of its best point. I would guess the best power from such an engine is at a much higher speed.