What is measured by the power of the electric current. Electrical Power: Formula, Units of Measurement

If you need a power measurement unit to bring in one system, you will use our power transfer - an online converter. And below you can read what power is measured.

Power - physical quantityequal to the ratio of work performed for a certain period of time, by this period of time.

What is the measuring power?

Power measurement units that are known to each schoolchildren are accepted in the international community - watts. Named so in honor of the scientist J. Watt. Indicated Latin W or W.

1 watt - a unit of measurement of power at which a second joule operation occurs in a second. Watt is equal to the power of the current, the strength of which is 1 ampere, and voltage is 1 volt. The technique, as a rule, apply megawatts and kilowatts. 1 kilowatt is 1000 watt.
The power is measured and in ERG per second. 1 erg per second. Equal to 10 in minus the seventh degree watt. Accordingly, 1 watt is 10 in the seventh degree of erg / s.

And another unit of measurement of power is considered an incident "horsepower". It was introduced in turnover in the eighteenth century and continues to be applied in the automotive industry. It is true:

L.S. (in Russian),
HP (in English).
PS (in German),
CV (French).

When translating power, remember that there is an unimaginable confusion in RuNet with the envelope of horsepower in Watta. In Russia, CIS countries and some other states 1 hp equals 735, 5 watts. In England and America 1 HP equals 745, 7 watts.

Hello! To calculate the physical quantity, called power, use the formula where physical quantity - work is divided for a time for which this work was produced.

She looks like this:

P, W, N \u003d A / T, (W \u003d J / s).

Depending on the textbooks and sections of physics, the power in the formula may be denoted by the letters P, W or N.

Most often power is applied, in such sections of physics and science, as mechanics, electrodynamics and electrical engineering. In each case, power has its own formula for calculating. For AC and DC, it is also different. Wattmeters are used to measure power.

Now you know that power is measured in watts. In English Watt - Watt, international designation - w, russian abbreviation - W. It is important to remember because in all household appliances There is such a parameter.

Power is a scalar value, it is not a vector, in contrast to the strength that may have direction. In mechanics, the general view of the power formula can be written as:

P \u003d f * s / t, where f \u003d a * s,

From the formulas can be seen, as we instead of substitut the power of F multiplied by the path s. As a result, the power in the mechanics can be recorded, as the force multiplied by speed. For example, having a car certain power, I have to reduce the speed when driving up the mountain, as it requires greater strength.

The average power of a person is accepted for 70-80 W. The power of cars, airplanes, ships, rockets and industrial installations is often measured in horsepower. Horsepower used long before the introduction of Watt. One horsepower is 745.7W. And in Russia it is made that l. from. equal to 735.5 W.

If you suddenly accidentally ask in 20 years in an interview among passersby about power, and you remember that power is the ratio of work A, perfect per unit of time t. If you can say so, pleasantly surprise the crowd. After all, in this definition, the main thing is to remember that the divider is working here a, but a dividious time t. As a result, having a job and time, and dividing the first to the second, we will get long-awaited power.

When choosing in stores, it is important to pay attention to the power of the device. The more powerful the kettle, the faster it will get water. The air conditioner power determines which size of the space it can cool without extreme load on the engine. The greater the power of the electrical appliance, the more current it consumes, the more electricity will spend, the greater the fee for electricity.

IN general Electrical power is determined by the formula:

where I is the current strength, U-voltage

Sometimes even it is measured in a volt-ampere, recording like in * a. In the Volt-amperes measure full power, and to calculate the active power you need to multiply the efficiency of the efficiency (efficiency) of the instrument, then we obtain active power in watts.

Often, such devices like air conditioning, refrigerator, iron work cyclically, including and disconnecting from the thermostat, and their average power for the total working time may be small.

In alternating current chains, in addition to the concept of instantaneous power, which coincides with the media, there are active, reactive and complete power. Full power equal to the sum of active and reactive capacity.

Electronic devices are used to measure power - wattmeters. The unit of measurement of WATT, received its name in honor of the inventor of an improved steam car, which made a revolution among the energy attitudes of that time. Due to this invention, the development of industrial society accelerated, trains, steamboats, plants that use the steam engine for the movement and production of products appeared.

We all faced many times with the concept of power. For example, different cars are characterized by different engine power. Also, electrical appliances may have different power, even if they have the same destination.

Power is a physical value that characterizes the speed of work.

Respectively, mechanical power is a physical value that characterizes the speed of mechanical work:

That is. Power is a job per unit of time.

Power in the SI system is measured in watts: [ N.] \u003d [W].

1 W is a job in 1 J, perfect for 1 s.

There are other power measurement units, such as horsepower:

It is in horsepower that the power of the car engine is most often measured.

Let's go back to the formula for power: the formula for which the work is calculated, we know: Therefore, we can convert the expression for power:

Then in the formula, we have a relationship of the movement module by the time interval. This is how you know the speed:

Just note that in the resulting formula we use the speed module, because at the time we divided not to move itself, but its module. So, the power is equal to the product of the force module, the speed module and cosine of the angle between their directions.

It is quite logical: let's say, the power of the piston can be increased by increasing its strength. Applying great strength, it will make more work for the same time, that is, it will increase power. But even if you leave the power constant, and make the piston move faster, it will undoubtedly increase the work performed per unit of time. Consequently, power will increase.

Examples of solving problems.

Task 1.Motorcycle power is equal to 80 hp Moving along the horizontal site, the motorcyclist develops the speed of 150 km / h. At the same time, the engine runs 75% of its maximum power. Determine the force of friction acting on a motorcycle.

Task 2.The fighter, under the action of constant thrust, directed at an angle of 45 ° to the horizon, accelerates from 150 m / s to 570 m / s. At the same time, the vertical and horizontal speed of the fighter increases to the same value at each moment of time. The mass of the fighter is 20 tons. If the fighter accelerates for one minute, then what is the power of its engine?

Electric power - Physical value characterizing the transfer rate or transformation of electrical energy.

Encyclopedic YouTube.

1 / 5

✪ Lesson 363. Power in chains alternating current

✪ Active, reactive and complete power. What it is, on the example of a visual analogy.

✪ Work and power electric current. Current current | Physics Grade 8 # 19 | Infourok.

✪ What is the difference between voltage and current

✪ watt joule and horsepower

Subtitles

Instant electrical power

Instant power is a product of instantaneous voltage and current values \u200b\u200bon any section of the electrical circuit.

DC power

Since the values \u200b\u200bof the current and voltage strength are constant and are equal to instantaneous values \u200b\u200bat any time, the power can be calculated by the formula:

P \u003d I ⋅ U (\\ DisplayStyle P \u003d I \\ Cdot U) .

For a passive linear chain, in which the Ohm law is observed, you can write:

P \u003d i 2 ⋅ r \u003d u 2 r (\\ displaystyle p \u003d i ^ (2) \\ Cdot R \u003d (\\ FRAC (U ^ (2)) (R)))where R (\\ DisplayStyle R) - electrical resistance .

If the chain contains an EDC source, then the electrical power absorbed on it or absorbed on it is equal to:

P \u003d i ⋅ E (\\ displayStyle P \u003d I \\ CDOT (\\ Mathcal (E)))where E (\\ DisplayStyle (\\ Mathcal (E))) - EDF.

If the current inside the EDC is equivalent to the potential gradient (flowing inside the EDC from the plus to minus), then the power is absorbed by the EDC source from the network (for example, when the electric motor or battery charge), if co-directed (flows inside the EDC from a minus to the plus), then the source is given On the network (let's say, when operating a galvanic battery or generator). When taking into account the internal resistance of the EDS source allocated on it P \u003d i 2 ⋅ R (\\ displaystyle p \u003d i ^ (2) \\ Cdot R) Added to absorbing or deducted from the given.

AC power

In alternating current circuits, power formula direct current It can only be applied to calculate instantaneous power, which is much changed over time and for most of the simple practical calculations is not too useful directly. The direct calculation of the average power value requires time integration. To calculate power in chains, where the voltage and current change periodically, the average power can be calculated, integrating instantaneous power during the period. In practice, the greatest value is the calculation of power in the chains of variable sinusoidal voltage and current.

In order to associate the concepts of complete, active, reactive capacity and power factor, it is convenient to refer to the theory of complex numbers. It can be assumed that the power in the AC circuit is expressed in a complex number such that the active power is its actual part, the reactive power - imaginary part, full power - module, and the angle (phase shift) - argument. For such a model, all relations discharged below are valid.

Active power

Reactive power - a value that characterizes the loads created in electrical devices The fluctuations in the energy of the electromagnetic field in the sinusoidal alternating current circuit is equal to the product of the range of regulatory voltage values U (\\ DisplayStyle U) and current I (\\ DisplayStyle I)multiplified by the sine angle of shift phases φ (\\ displayStyle \\ Varphi) Between them: Q \u003d U ⋅ i ⋅ sin \u2061 φ (\\ displaystyle q \u003d u \\ cdot i \\ cdot \\ sin \\ varphi) (If the current is lagging behind the voltage, the phase shift is considered positive if ahead is negative). Reactive power is associated with full capacity S (\\ DisplayStyle S) and active power P (\\ DisplayStyle P) By the ratio: | Q | \u003d S 2 - P 2 (\\ displaystyle | q | \u003d (\\ sqrt (s ^ (2) -p ^ (2)))).

The physical meaning of the reactive power is the energy pumped from the source to the reactive elements of the receiver (inductance, capacitors, engine winding), and then returning to the source in the source during one period of oscillations, referred to this period.

It should be noted that the value for values φ (\\ displayStyle \\ Varphi) From 0 to plus 90 ° is a positive value. Value SIN \u2061 Φ (\\ DisplayStyle \\ Sin \\ Varphi) For values φ (\\ displayStyle \\ Varphi) From 0 to -90 ° is a negative value. In accordance with the formula Q \u003d u i sin \u2061 φ (\\ displaystyle q \u003d ui \\ sin \\ varphi), reactive power can be as a positive value (if the load has an active-inductive character), and negative (if the load has an active-capacitive character). This circumstance emphasizes the fact that reactive power does not participate in the operation of the electric current. When the device has a positive reactive power, it is customary to say that it consumes it, and when negative - it produces, but it is a net conventional due to the fact that most of the power consumption (for example, asynchronous motors), as well as a purely active load, connected Through the transformer, are active inductive.

Synchronous generators installed at electrical stations can both produce and consume reactive power depending on the magnitude of the excitation current flowing in the generator rotor winding. Due to this feature of synchronous electric machines Adjusts the specified network voltage level. To eliminate overload and increasing the power factor electrical installations Compensation of reactive power is carried out.

The use of modern electrical measuring transducers on microprocessor equipment allows you to produce a more accurate estimate of the amount of energy returned from inductive and capacitive load into the source of alternating voltage.

Full power

Unit full electrical power - Volt-amp ( russian designation: B · A.; International: V · A.) .

Complete power - the value equal to the product of the current values \u200b\u200bof the periodic electric current I (\\ DisplayStyle I) in chains and voltages U (\\ DisplayStyle U) On her clamps: S \u003d U ⋅ I (\\ DisplayStyle S \u003d U \\ Cdot i); associated with active and reactive capacity by the ratio: S \u003d p 2 + q 2, (\\ displaystyle s \u003d (\\ sqrt (p ^ (2) + q ^ (2))),) Where P (\\ DisplayStyle P) - active power, Q (\\ DisplayStyle Q) - reactive power (with inductive load Q\u003e 0 (\\ DisplayStyle Q\u003e 0), and when capacitive Q.< 0 {\displaystyle Q<0} ).

The vector relationship between the full, active and reactive power is expressed by the formula: S ⟶ \u003d p ⟶ + q ⟶. (\\ DisplayStyle (\\ Stackrel) \u003d (\\ Stackrel (\\ Longrightarrow) (P)) + (\\ Stackrel (\\ LongrightArrow) (Q)).)Comprehensive power

Power, similar to impedance, can be written in a comprehensive form:

S ˙ \u003d u ˙ i ˙ * \u003d i 2 z \u003d u 2 z *, (\\ displaystyle (\\ dot (s)) \u003d (\\ dot (u)) (\\ dot (i)) ^ (*) \u003d i ^ (2) \\ Mathbb (z) \u003d (\\ FRAC (U ^ (2)) (\\ Mathbb (z) ^ (*))),) Where U ˙ (\\ DisplayStyle (\\ Dot (U))) - complex tension, I ˙ (\\ DisplayStyle (\\ Dot (I))) - Complex current, Z (\\ displaystyle \\ mathbb (z)) - Impedance, * - a complex pairing operator.

Complex power module | S ˙ | (\\ DisplayStyle \\ Left | (\\ Dot (S)) \\ Right |) equal to complete power S (\\ DisplayStyle S). Actual part R e (s ˙) (\\ DisplayStyle \\ Mathrm (Re) ((\\ Dot (S)))) equal to active power P (\\ DisplayStyle P), and imaginary I m (s ˙) (\\ displaystyle \\ mathrm (im) ((\\ dot (s)))) - reactive power Q (\\ DisplayStyle Q) With correct sign, depending on the nature of the load. Power of some electrical appliances

The table indicates the power values \u200b\u200bof some electrical current consumers:

Electrical appliance	Power, W
lantern light bulb	1
network router, hub	10…20
pC system unit	100…1700
system Unit Server	200…1500
monitor for PC CRT	15…200
monitor for PC LCD	2…40
luminescent household lamp	5…30
household incandescent lamp	25…150
Refrigerator household	15…700
Electric flows	100… 3000
Electric Iron.	300…2 000
Washer	350…2 000
Electric tile	1 000…2 000
Welding apparatus household	1 000…5 500
Tram engine	45 000…50 000
Engine Electrovoza	650 000
Motor of a shaft lifting machine	1 000 000...5 000 000
Rolling mill electric motors	6 000 000…9 000 000

What is power and power? What is measured by this indicator, while the instruments are used, and as mentioned physical quantities are applied in practice, we will look at the article further.

Force

In the world, all body physical nature begins to move through force. With its impact, with a passing or opposite direction of the body movement, work is performed. Thus, any power affects the body.

So, the bike begins with the place due to the power of the person's feet, and the electric locomotive thrust acts on the train. This impact happens at any movement. The work of strength is the value in which the power module is multiplied by the module for moving the point of its application and the cosine of the angle between these indicators. The formula in this case looks like this:

If the angle between these vectors is not equal to zero, then the work is always done. At the same time, it can have both positive and negative meaning. The body will not act at the corner, equal to 90 °.

Consider for an example a cart that the muscular power of a horse pulls. In other words, the work makes the force of thrust in the direction of the traffic of the cart. But the power of gravity, directed down or perpendicularly, does not work (by the way, horsepower is what the engine power is measured).

Work work is a scalar value and is measured in Joules. She may be:

relaxing (when exposed to several forces);
non-permanent (then the calculation is made with the integral).

Power

What is the measured this value? To begin with, we will analyze that it represents. It is clear that the movement of the body begins at the expense of the force performing mechanical work. However, in practice, in addition, it is necessary to know exactly how it is committed.

that is, the product of the vectors of force on the speed of movement - and there is power. What is it measured? According to the international system C, the unit of measurement of this value is 1 watt.

Watt and other power measurement units

Watt means the power, where in one second work is done in one joule. The last unit was called so in honor of the British J. Uatta, who invented and built the first steam car. But at the same time it used another value - horsepower, which is used to this day. One horsepower is approximately 735.5 watts.

Thus, besides watt, power is measured in metric horsepower. And with a very small value, ERG is also used equal to ten in minus the seventh degree of watts. It is possible to measure in one unit of mass / strength / meters per second, which is 9.81 watts.

Engine power

The title is one of the most important in any motor that has the most different power. For example, an electric razor has hundredths of kilowatt, and the rocket of the spacecraft has millions.

For different loads, various power is needed to save certain speed. For example, the car will become harder if more cargo put it. Then the friction force about the road will increase. Therefore, in order to maintain the same speed as in unloaded state, high power will be required. Accordingly, the motor will eat more fuel. About this fact is known to all drivers.

But at high speed, the inertia of the machine, which is directly proportional to its mass. The experienced drivers who know about this fact find when driving the best combination of fuel and speed so that gasoline goes less.

Current power

What is the current current? In the same unit of SI system. It can be measured by a direct or indirect method.

The first method is implemented using a wattmeter that consumes substantial energy and a heavily loading current source. With it, it is measured from ten watts and more. An indirect method is used if necessary to measure small values. Devices for this serve as an ammeter and a voltmeter connected to the consumer. The formula will in this case will have such a form.

Each modern device has electrical power. Its digital value is indicated by the manufacturer on the body of the hair dryer or an electric kettle, on the cover of the kitchen combine.

Units

The calculation of electrical power allows determining the cost of electrical energy consumed by different devices during a certain period of time. Watts and kilowatts in excessive amounts lead to the failure of wires, deformation of contacts.

Dependence between the electrical current and power consumed by the instruments

Electrical power is a job that is performed during the period of time. The instrument included in the outlet makes the work that is measured in watts (W). The case indicates the amount of energy that will be consumed by the instrument for a certain period of time, that is, the electric power consumed is given.

Power consumption

It is consumed that electron moves in the explorer. In the case of one electron having a single charge, it is comparable from the value of the network voltage. Complete energy that is necessary to move all electrons will be determined as a product of voltage to the number of electrons in the chain when the electrical instrument is operating. Below is an electrical power formula:

Considering that the number of electrons flowing over the period of time through the transverse cross section of the conductor is an electric current, it is possible to submit it to the expression for the desired value. Electrical power formula will look:

In reality, it is necessary to calculate the power itself, but the value of the current, knowing the voltage of the network and the nominal power. By defining a current that is consumed by a specific device, you can relate the nominal socket and the circuit breaker.

Examples of calculations

For the kettle, the electrical power of which is designed for two kilowatta, the current consumed is determined by the formula:

I \u003d p / u \u003d (2 * 1000) / 220 \u003d 9a

To connect such a device into a regular electrical network, a connector, designed for 6 amps, is clearly not suitable.

The dependences of the dependences between the power and the electric current are appropriate only with the full coincidence of the phase of voltage and current values. For almost all household electrical appliances, an electrical power formula is suitable.

Exceptional situations

In the event that there is a large container or inductance in the chain, the formulas used will be unreliable, they cannot be used to conduct mathematical calculations. For example, the electrical power for the AC motor will be determined as follows:

cosφ is a power coefficient that is 0.6-0.8 units for electric motors.

Determining the parameters of the device in a three-phase network with a voltage of 380 V, it is necessary to summarize the power from individual values \u200b\u200bfor each phase.

Example of calculation

For example, in the case of a three-phase boiler, calculated on the power of 3 kW, each phase consumes 1 kW. Calculate the values \u200b\u200bof the phase current by the formula:

I \u003d p / u_f \u003d (1 * 1000) / 220 \u003d 4,5A.

For a modern person, a constant use in production and in everyday life of electricity is characterized. It uses instruments that consume electric current uses such devices that produce it. Working with such sources, it is important to take into account the maximum features that are assumed in the specifications.

Such a physical value, as an electric power, is one of the main indicators of any device operating when electron flow through it. For transportation or transmission of electrical capacities in the large volume required in production conditions, high-voltage lines of electrical gear are used.

Energy conversion is performed on powerful transformer substations. Three-phase transformation is characteristic of industrial and household appliances of different applications. For example, thanks to such a transformation, there are incandescent lamps of different nominal nominal.

In theoretical electrical engineering there is such a concept as an instantaneous electrical power. This value is associated with flowing through a certain surface for a slight time interval of a single elementary charge. The work is performed by this charge, which is associated with the concept of instantaneous power.

Performing simple mathematical calculations, you can determine the power value. Knowing this amount, you can select the voltage for the full functioning of various diverse and industrial instruments. In this case, you can avoid risks associated with the burning of expensive electrical devices, as well as the need to periodically change electrical wiring in the apartment or the office.

Kilowatt - a multiple unit formed from Watt

Watt

Watt (W, W) - a system unit of power measurement.
Watt - Universal derivative unit in the SI system having a special name and designation. As a unit of power measurement, "Watt" was recognized in 1889. At the same time, this unit was named after James Watt (Watta).

James Watt. - A man who came up with and made a universal steam car

As a derivative unit of SI, "Watt" was included in it in 1960.
Since then, the power is measured in watts.

In the SI system, in watts, it is allowed to measure any power - mechanical, thermal, electrical, etc. Also allowed the formation of multiple and dolle units from the source unit (Watt). To do this, it is recommended to use a set of standard prefixes of the SI system, type - kilo, mega, giga, etc.

Units of measurement of power, multiple watts:

1 watt
1000 watt \u003d 1 kilowatt
1000 000 watt \u003d 1000 kilowatt \u003d 1 megawatt
1000 000 000 watt \u003d 1000 megawatt \u003d 1000 000 kilowatt \u003d 1gigavatt
etc.

Kilowatt-hour

There is no such unit of measure in the System system.
Kilowatt-hour (kw⋅h, kw⋅h) is an incidental unit that is derived exclusively for accounting used or generated electricity. The number of consumed or generated electricity is taken into account in kilowatt-hours.

The use of "kilowatt-hour", as a unit of measure, in Russia regulates GOST 8.417-2002, in which the name, designation and scope for Kilowatt-hour is uniquely indicated.

Download GOST 8.417-2002 (Dropping: 3014)

Exposure from GOST 8.417-2002 "The state system for ensuring unity of measurements. Units of quantities ", P.6 units that are not included in the SI (Fragment of Table 5).

Introduced units allowed to use on a par with SI units

What is needed kilowatt-hour

GOST 8.417-2002 It recommends using a "kilowatt-hour" as the main unit of measurement for taking into account the number of electricity used. Because "kilowatt-hour" is the most convenient and practical form that allows the most acceptable results.

At the same time, GOST 8.417-2002 absolutely does not object to the use of multiple units formed from Kilowatt-hour in cases where it is appropriate and necessary. For example, with laboratory work or when taking into account the generated electricity at power plants.

Educated multiple units from Kilowatt-hour look, respectively:

1 kilowatt-hour \u003d 1000 watt-hour,
1 megawatt hour \u003d 1000 kilowatt-hour,
etc.

How to write kilowatt-hour

The spelling of the term "kilowatt-hour" according to GOST 8.417-2002:

complete name you need to write through a hyphen:
watt-hour, kilowatt-hour
brief designation must be written through the point:
VT⋅ch, kw⋅h, kw⋅h

Approx. Some browsers incorrectly interpret the HTML page code and instead of a point (⋅) displays a question mark (?) Or other Krakoyar.

GOST 8.417-2002

Most of the national technical standards of the current post-Soviet countries are linked to the standards of the former union, therefore, in the metrology of any country of the post-Soviet space, you can find an analogue of Russian GOST 8.417-2002, or a reference to it, or its processed option.

Power designation electrical appliances

Generally accepted practice - denote the power of electrical appliances on their housing.
The following symbol of electrical equipment is possible:

in watts and kilowatts (W, kW, w, kw)
(Designation of mechanical or thermal power of electrical appliance)
in watt clock and kilowatt-hours (VT⋅ch, kw⋅ch, W⋅h, kw⋅h)
(Designation of electrical power consumption of electrical appliance)
in Volt-amperes and kilovolt amperes (VA, KVA)
(designation of total electrical power of electrical appliance)

Units of measurement to indicate the power of electrical appliances

watt and Kilowatt (W, kW, w, kw) - Units of measurement of power in the system system are used to designate the general physical power of anything, including electrical appliances. If there is a designation in watts or kilowatts on the housing of the electrical unit - this means that this electro-unit, during its work, develops the specified power. As a rule, in "watts" and "kilowatts" indicates the power of the electrical unit, which is the source or consumer of the mechanical, thermal or other type of energy. In the "watts" and "kilowatts" it is advisable to designate the mechanical power of electric generators and electric motors, thermal power of electric heating devices and aggregates, etc. The designation in "watts" and "kilowatts" produced or consumed the physical power of the electrical unit occurs, provided that the use of the concept of electrical power will disorient the final consumer. For example, the amount of heat obtained is important for the electric heater owner, and then electrical calculations.

watt-hour and kilowatt-hour (W⋅Ch, kw⋅Ch, W.⋅h, kw.⋅h) - Introduced units of measurement of electrical energy consumed (power consumption). Power consumption is the amount of electricity consumed by electrical equipment per unit time of its work. Most often, the "watt clock" and "kilowatt-clock" are used to designate the power consumed of household electrical engineering, according to which it actually choose.

volt-ampere and kilovolt ampere (VA, KVA, VA, KVA) - Units of measurement of electrical power in the SI system, equivalent watts (W) and kilowatt (kW). Used as units of measurement of the value of the total power of the AC. Volt-amps and kilovolt amps are used in electrotechnical calculations in cases where it is important to know and operate precisely by electrical concepts. In these measurement units, it is possible to denote the electrical power of any electrical appliance of the AC. Such a designation will most comply with the requirements of electrical engineering, from the point of view of which - all electrical appliances of AC are active and reactive components, so the total electrical power of such an instrument must be determined by the sum of its parts. As a rule, in "Volt-amperes" and multiple them are measured and denoted by the power of transformers, chokes and other, purely electrical transducers.

The choice of measurement units in each case occurs individually, at the discretion of the manufacturer. Therefore, you can find household microwaves from different manufacturers, the capacity of which is indicated in kilowatts (kW, kW), in kilowatt-hours (kWh, kw⋅h) or in Volt-amperes (VA, VA). Both the first and second, and the third - there will be no mistake. In the first case, the manufacturer indicated thermal power (as a heating unit), in the second - consumed electrical power (as an electromotive), in the third - complete electrical power (as an electrical appliance).

Since the household electrical equipment is sufficiently low to take into account the laws of scientific electrical engineering, on the household level, all three digits - almost coincide

Considering the above, you can answer the main question of the article

Kilowatt and kilowatt-hour | What's the difference?

The biggest difference is that Kilowatt is a unit of measurement of power, and kilowatt-hour is a unit of measuring electricity. The confusion and confusion arises on the household level, where the concepts of kilowatt and kilowatt-hour are identified with the measurement of the produced and consumed power of the household electrical appliance.
At the level of the household appliance, the electroplator - the difference is only in the separation of the concepts of energy issued and consumed. In kilowatts, the heat or mechanical power of the electrical unit is measured. In kilowatt-hours, the electric power consumption of the electrical unit is measured. For household electrical appliances, the numbers produced (mechanical or heat) and consumed (electrical) energy practically coincide. Therefore, there is no difference in everyday life, in what concepts to express and in which units to measure the power of electrical appliances.
The binding of units of measuring kilowatt and kilowatt-hour is applicable only for cases of direct and reverse transformation of electrical energy into mechanical, thermal, etc.
It is absolutely unacceptable to use a unit of measurement "kilowatt-hour" in the absence of the process of transformation of electricity. For example, in Kilowatt-hour, it is impossible to measure the power consumption of the wood heating boiler, but you can measure the power consumption of the electric heating boiler. Or, for example, in Kilowatt-hour, it is impossible to measure the power consumption of the gasoline engine, but you can measure the power consumption of the electric motor
In the case of direct or reverse transformation of electrical energy into mechanical or thermal, link kilowatt-hour with other units of energy measurement can be using an online calculator of the website TEHNOPOST.KIEV.UA: