1 h.p. equal to 0.7355 kW when calculating the motor power.
Story
Horsepower (hp) is a non-systemic unit of power that appeared around 1789 with the advent of steam engines. Inventor James Watt coined the term "horsepower" to illustrate how economically his machines are more economically viable than live draft. Watt found that, on average, one horse lifts 180 pounds by 181 feet per minute. Rounding off the calculations in pound-feet per minute, he decided that horsepower would be 33,000 of those pound-feet per minute. Of course, the calculations were taken for a long period of time, because for a short time a horse can "develop" a power of about 1000 kgf · m / s, which is approximately equal to 13 horsepower. This power is called boiler horsepower.There are several units of measurement in the world called "horsepower". In European countries, Russia and the CIS, as a rule, under horse power refers to the so-called "metric horsepower", equal to approximately 735 watts (75 kgf · m / s).
In the automotive industry in the United Kingdom and the United States, HP is most commonly used. equates to 746 watts, which equals 1.014 metric horsepower. Electric horsepower (746 W) and boiler horsepower (9809.5 W) are also used in industry and energy in the United States.
Horsepower as a unit of measurement of power first appeared in the 18th century, when steam engines were put into operation. James Watt, a renowned inventor, used these words to explain the superiority of technology over animals. He concluded that one horse was capable of lifting 180 pounds of merchandise 181 feet.
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After calculating, Watt determined that horsepower was 33,000 animal pound-feet per minute. Over time, his theory changed, the calculations were checked and corrected. So there were several units of measurement, and with them calculators for converting kilowatts to horsepower.
What is it for
V different countries horsepower is understood in different ways. In Russia, the CIS countries and several others, they are called metric and equated to watts. In European countries, it is considered the power that is required when lifting a product weighing 75 kg at a speed of meter / s with an acceleration of 75 kgf m / s.
These calculations are close to those of Watt and more accurately show how many animals would be required to replace the work of one machine. In 2019 they are used for other purposes, but the idea remains the same.
When Watt popularized his theory, not only did different systems of measurement emerge, but also different formulations and reasons for using horsepower.
They are not official when measuring the engine of a car, but they are used in 4 options:
- in Russia the metric system of measurement is adopted. It is equal to the power required to lift a load of a certain weight at a certain speed. To calculate the forces, you need to multiply them by watts;
- in electrics and electromechanics, electrical force is recognized. To count anything in horses, you must divide them by 746. For example, 4,000 watts equals 5.37 horsepower;
- in the UK and some other countries, mechanical force is used. To count in horses, it is enough to multiply them by 745.7 watts;
- Boiler power is used in the energy and industrial sectors. To count anything in horses, you need to use following formula: 9.809 kW = 1 hp
Horsepower has gained great popularity all over the world due to its convenience, its meaning is understandable to every user, there is no need to study auto mechanics and technical characteristics.
Citizens understand what a transport with a capacity of 100 horsepower is capable of, and the same number in kilowatts is misleading, although the numbers express the same thing.
After Watt came up with the original formula, scientists recalculated the numbers several times and proved that horses cannot develop enough power to lift 75 kg of goods upward at the required speed. Watt calculated forces in mines where little ponies were used.
It turned out that he had multiplied his calculations by half to show the efficiency of the machines. Watt was able to successfully sell steam engines by exaggerating reality, and horsepower began to be used all over the world.
table of correspondence
There are 2 main tables: for converting from kilowatts to horsepower and vice versa:
Translation formula
In Russia, a special formula has long been developed that allows you to translate one meaning into another.
1 hp = 735.499 W
This equation is approximate and cannot be used in professional papers, but it is great for checking the amount of car tax or the value of the policy.
In Russia, horsepower is often used in technical descriptions of cars, and watts are used in international documents. The formula helps to avoid misunderstandings.
Procedure
When it is required to calculate the power, it turns out that this designation corresponds to the vertical lifting of a product weighing 75 kg at a speed of 1 m / s with normal acceleration. One horse power in Russia is equal to 735.49875 watts. It is important to remember that these numbers are not a systematic unit of measurement.
Mechanics have made great strides since the 18th century, the development of the industry has led to the emergence of many horsepower, each has its own application.
The presence of several units of measurement has led to the need to regularly transfer power from one system to another.
In 1960 was adopted one system SI, in most states, they officially began to count in watts. Horses are used in the automotive industry by amateur motorists, professionals have switched to watts.
In the UK, the adjusted value is still used, which is calculated using the formula:
745.69988145 W = 1 HP
To understand which country the horsepower is indicated in, in technical characteristics put the notation:
- PS Germany;
- CH France;
- HP UK;
- PK Holland.
To convert the value from kilowatts to Russian horsepower, you will need to apply the formula:
1 kW = 1.3596 hp With.
In the United States, electrical forces are used, which are calculated according to the following values:
746W = 1 Boiler horsepower
This value in America is mainly applied in the energy industry.
How to use the calculator online
To translate some units of measurement yourself into others, you just need to use online calculator ohm:
- enter kilowatts or;
- introduce horsepower.
The calculator will automatically display the actual value.
The concepts that appeared in the past are gradually disappearing. Increasingly, you can find watts instead of horsepower. In order not to get confused, there are online calculators for easy translation.Any motorist is familiar with the phrase "horsepower". Since in the old days, heavy lifting was done by horses, this concept was very convenient. Later, a steam boiler (machine) began to be used as a pushing force, therefore, automatically, to measure its power, they began to use a comparison with the power of all the same horses (that is, how many heads of this animal would be required to perform this work). This term came into use at the end of the 18th century, its “ godfather"Is considered the famous inventor - Englishman J. Watt. However, in our time, ungulates are being replaced by the metric system "SI", where power is measured already in watts or kilowatts.
How to convert horsepower to kW
And in Europe, and after it in Russia, it is increasingly accepted to express the power of vehicles in kilowatts. However, in many technical documents, the familiar horse still appears, so sometimes difficulties arise in determining the power. vehicle... It is necessary to convert kilowatts to horsepower and vice versa. The interdependencies are disclosed below.
Important! For the power of one horse (hence, one horsepower), it is customary to take the value of 0.735 kilowatts. At the same time, one kilowatt equates to 1.36 horsepower.
Note! Often, to simplify the calculation, this value is rounded up to 1.4 hp. The conversion of kilowatts to horsepower is carried out by multiplying by this factor. So, a car with a capacity of 88 kW has 120 l / s under the hood. And, conversely, in order to calculate how many kilowatts the power, expressed in "horses", denotes, it should be divided by the same 1.4. For example, a 180 hp motor. means 132 kW, and 150 hp. - 110 kW.
For an easy conversion of kW into horsepower (hp) and vice versa, there is an online calculator and more than one - there are a lot of resources on the network that make life easier for motorists in this way. Many web pages also contain ready-made tables for translating one measure into another.
Why exactly 0.735 kW?
So where did this 1 horsepower value come from? As well as many other things in physics - through experiments. It turned out that one horse (for the experiments, as a rule, 4-year-old adults were taken) would move a load of 75 kg (why not 70 or 80, it is not known for certain) and pull it 1 meter in one second.
It is interesting that in a strong, normally developed animal, a power equal to ten to twelve "horses" is measured, which significantly exceeds human capabilities.
Additional Information. In European countries, as in our country, 735.4987 W is taken for one horsepower (arb.bhp, German PS), while in America and England, it is 745.69988 W, which is why there are some discrepancies. For example, such.
Horsepower discrepancy table
Moreover, in addition to ordinary horsepower, there are mechanical, electrical, boiler values of this value. Engine power measured at the bench (declared) will not fully equal the real one due to the imposition of transmission losses.
Practical aspect
In practice, it is very important to know how many "horses" the engine of this or that car accelerates. The definition of the class of the car, its dynamic characteristics depends on this indicator. Therefore, in the data sheets for the car, the engine power in horsepower is necessarily prescribed. This indicator is also very important for calculating the tax base for the transport tax, as well as for payments for OSAGO insurance.
There are different rates for different power categories. With the increase in the number of "horses" under the hood, you have to pay a higher tax. Such a graduated system was introduced for fairer taxation.
It is important for any motorist to be able to translate engine power, expressed in horsepower, into more modern kilowatts, a simple formula will help them with this:
1 kilowatt [kW] = 1.34 hp.
You can also use online calculators for translation.
Video
Horsepower is a unit of power. It is approximately equal to the value of 75 kgf / m / s, which corresponds to the effort that must be expended to lift a load of 75 kg. to a height of one meter in one second.
What is 1 horsepower? If you take any encyclopedia and look at what horsepower is, then we will read that it is a non-systemic unit of measurement of power that is not used in Russia. Although on any website of dealership car dealerships, engine power is indicated in horsepower.
What is this unit, what is it equal to?
When talking about engine horsepower, most of us have a simple picture: if you take a herd of 80 horses and a car with an engine power of 80 hp, then their forces will be equal and no one can pull the rope.
If you try to recreate such a situation in real life, then the herd of horses will win, because in order for the engine to develop such power, it needs to spin the crankshaft to a certain number of revolutions per minute. Horses will dash off and drag the car behind them, thus breaking its gearbox.
In addition, you need to understand that horsepower is a standard unit of power, while each horse is individual and some individuals can be much stronger than others.
Horsepower was introduced into circulation back in 1789. The famous inventor James Watt wanted to demonstrate how much more profitable it is to use steam engines rather than horses to get the job done. He simply took and calculated how much energy the horse spends in order to use the simplest lifting mechanism - a wheel with ropes attached to it - to pull barrels of coal out of the mine or pump out water using a pump.
It turned out that one horse can pull a load weighing 75 kilograms at a speed of 1 m / s. If we translate this power into watts, it turns out that 1 hp. is 735 watts. The power of modern cars is measured in kilowatts, respectively 1 hp. = 0.74 kW.
To convince the owners of the mine to switch from horse power to steam, Watt proposed a simple way: measure how much work horses can do in a day, and then plug in the steam engine and calculate how many horses he can replace. It is clear that the steam engine proved to be more profitable because it was able to replace a certain number of horses. The mine owners realized that it was cheaper for them to maintain a car than a whole stable with all the ensuing consequences: hay, oats, manure, and so on.
It is also worth mentioning that Watt miscalculated the strength of one horse. Only very strong animals are capable of lifting 75 kg at a speed of 1 m / s; moreover, they will not be able to work for a long time in such conditions. Although there is evidence that for a short time one horse can develop power up to 9 kW (9 / 0.74 kW = 12.16 hp).
Types of horse power
- Metric horsepower is equal to the rise of 75 kg per second per 1 meter. Applied in Europe
- Mechanical horsepower is equal to 745.7. very rarely used as a unit of measure in English speaking countries
- Electric horsepower equal to 746 W., sometimes indicated on the electric motor plates.
- Boiler horsepower is equal to 1000 kgf m / s. or 9.8 kW or 33 475 Btu / hour. (the unit is used in the USA)
- Hydraulic horsepower equal to 745.7 watts.
How engine power is determined
Today, the easiest way to measure the real power of an engine is with a dyno. The car is driven onto the stand, it is reliably strengthened, then the driver accelerates the engine to maximum speed and the display shows the real power in hp. Permissible error - +/- 0.1 hp. As practice shows, it often turns out that the rated power does not correspond to the real one, and this may indicate the presence of a wide variety of malfunctions - from poor-quality fuel to a drop in compression in the cylinders.
It is worth saying that due to the fact that horsepower is a non-systemic unit, it is calculated differently in different countries. In the USA and England, for example, one hp. is 745 watts, not 735 as in Russia.
Whatever it was, but everyone is already accustomed to this particular unit of measurement, since it is convenient and simple. In addition, h.p. used in calculating the cost of OSAGO and CASCO.
Agree if you read in the characteristics of the car - the engine power is 150 hp. - it is easier for you to navigate what he is capable of. And a record like 110.33 kW will say little. While converting kilowatts to hp quite simply: we divide 110.33 kW by 0.74 kW, we get the required 150 hp.
I would also like to remind you that the concept of "engine power" in itself is not very indicative, you also need to take into account other parameters: maximum torque, rpm, vehicle weight. It is known that diesel engines are low-speed and maximum power is reached at 1500-2500 rpm, while gasoline accelerates longer, but by long distances show top scores.
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Godfather of the famous unit "Horsepower" was the great 18th century English inventor James Watt, a member of the Royal Society of London and the Paris Academy of Sciences.
For many years Watt fought over the improvement of steam engines, and it was thanks to his work that by the 19th century, the entire industry switched to a new "draft force" - steam engines! Mines, factories, steamships, steam locomotives, automobiles, airplanes and even steam motorcycles - puffing steam engines were used everywhere, making wheels and shafts of mechanisms spinning briskly! The brainchild of J. Watt - the steam hammer took a leading place in metalworking enterprises, the era of steam heating, also invented by J. Watt, has come! Technological progress was advancing, so where did the antediluvian already at that time come from power unit"Horsepower"?
And what would a person do in our time trying to introduce something new and unknown? How to convince an entrepreneur that he cannot do without your invention?
So James Watt tried to prove the advantages of using his steam engines over the usual horses, on which all the equipment of that time was "held together".
After so many years, it is already difficult to reliably determine with the owner of which enterprise Watt agreed to replace horses with steam engines, what kind of horses they were: little ponies or tall rosinants, but the contract was concluded.
J. Watt had to prove that in the same time his car will do no less work of lifting loads than a strong horse! Do you think the owner entrusted the tests to Watt? Far from it! He himself for 8 hours from under the whip supported the "working spirit" of the poor horse, which brought it to complete exhaustion. And yet, during the same time, Watt's steam engine performed 4 times more work, which allowed the inventor to proudly announce that the power of his machine is 4 horsepower!
This is how the "horsepower" unit of power came into being.
So how much is 1 horsepower?
Measuring total weight The weight lifted by the horse and the height to which it was lifted over time, Watt calculated the power of the horse at work. It turned out that for 8 hours of work in "inhuman" conditions, the horse lifted about 2,000,000 kg of load to a height of one meter, which amounted to 75 kilograms per second.
Let's recall the formulas for mechanical work and power: A = FxS and N = A / t.
The “horsepower” unit of power corresponds to the power of a machine that lifts a 75 kg load every second to a height of 1 meter.
How strong is a horse really?
Later it turned out that without rest, the horse could not hold out for a long time at such a pace. During normal long-term operation, horse power is only one-third of the horsepower, i.e. in fact, 1 horsepower is significantly more power than the average horse can develop for at least one minute.
And if the horse is strained! Then we can measure the peak power, i.e. the upper limit of horse power. The measured peak horsepower in a few seconds is about 14.9 hp (sometimes referred to as "boiler" hp).
And the power of a racehorse is about 10 hp!
As one of the basic units, “horsepower lasted until the middle of the 20th century.
In October 1960. on the XI General Conference on Weights and Measures a new single International system SI units. In honor of the great scientist James Watt, the unit of power in this system was named Watt (W). And horsepower has become a non-systemic unit.
1 h.p. = 736 watts.
There are several units of measurement in the world called "horsepower", and the values of units of horsepower differ from one country to another.
In most European countries and in Russia 1 liter. With. is exactly 735.49875 W (sometimes it is called "metric horsepower", and in English-speaking countries, horsepower is still considered equal to 745.6999 W (about 1.014 European horsepower).
Horsepower is designated as PS (Pferdestärke) in Germany, as CV (cheval-vapeur) in France, as hp (horsepower) in England.
More than two hundred years have passed since the origin of the unit "horsepower", and it is still widely used. For example, still car engine power measured in horsepower.
But an interesting observation on the topic "Eh, I'll pump it over!"
Let's assume that the power of one horse pulling a cart with a load is equal to 1 hp.
And if you harness more horses to one team, how will their total power change?
It turns out that not everything is so simple!
The total power will be much less than expected! Restless horses will interfere with each other and the power of each of them will be the less, the more horses are in the team.
Calculated, tested and proven!
Number of sled horses - 2
Power of each horse - 0.92
Total power - 1.9
Number of sled horses - 3
Power of each horse - 0.85
Total power - 2.6
Number of sled horses - 4
Power of each horse - 0.77
Total power - 3.1
Number of sled horses - 5
Power of each horse - 0.7
Total power - 3.5
The number of sled horses - 6
Power of each horse - 0.62
Total power - 3.7
The number of sled horses - 7
Power of each horse - 0.55
Total power - 3.8
Number of sled horses - 8
The power of each horse is 0.47
Total power - 3.8
Here I am writing like a horse ...
And what is the "horsepower" of a person?
The power of an ordinary person, measured in horsepower, is only about 0.04 hp, and very rarely in the very strongest it reaches 0.25 hp. But! In exceptional conditions, a person on a short time a person can develop peak power up to 1 hp.
But it is estimated that digging the ground, a person does the same work in about an hour as a person does when walking, doing 5 km per hour. Therefore, the power of the excavator is at most 0.1 horsepower, i.e. the average power of a person during continuous work is about 80 W, i.e. about 0.1 hp
And in conclusion, the words of the famous physicist Soddy:
“From some points of view, a horse is an incredibly useful machine. What its effect, we didn’t imagine until the cars appeared, and instead of two horses usually harnessed to the carriage, it turned out to be necessary to harness at least 12 or 15, otherwise the car would stop at every hillock. "
So, long live the horse and "horsepower"!