When renovating or designing a new building, you have to analyze the electrical systems. To do this, you need to be able to work with various measuring quantities, for example, to represent amperes in kilowatts. In the home network, the voltage practically does not change, but you still need to know about the limits of the electric voltage, because it is taken into account when connecting devices of different powers.
Content
- Translation table
- Single-phase network
- Production voltage and power
Translation table
It is not entirely correct to talk about converting amperes to kilowatts, since these are different physical quantities. The first is used to measure the strength of the electric current, and the second shows the electric power. The conversion table is used to find out the correspondence between these values.
Tabular ratio (in one- and three-phase network):
-
2 A corresponds to 0.4 kW in the first phase and 1.3 kW in the third; - 6 amperes = 1.3 and 3.9 kW;
- 10 A reflects values of 2.2 and 6.6 kW, respectively;
- 16 A = 3.5 and 10.5 kilowatts;
- 20 amperes are presented as 4.4 and 13.2 kW;
- 25 And this is 5.5 kW of the first phase and 16.4 of the third;
- 32 A = 7.0 and 21.1 kW;
- 40 amperes is 8.8 and 26.3 kilowatts, respectively;
- 50A - 11.0 and 32.9 kW;
- 63 amps = 13, 9 and 41.4 kW.
These values will be useful when selecting circuit breakers or fuses. To do this, they find out the power of all electrical appliances - a washing machine, an air conditioner, incandescent lamps, a boiler or a computer. Or if the indicator of the rated current of the protective device is known, the power of the consumers can be calculated.
It is impossible to convert amperes to kW without one more value - the supply voltage. The standard value is indicated on the household network, and the nominal value can be recognized by the inscriptions on consumers and protective devices. It should also be borne in mind that a three-phase network is used in production, where the voltage value is higher than the household one.
Single-phase network
If a rated voltage of 30 A is indicated on the circuit breaker, then during normal operation an electric current must flow through it, the voltage of which does not exceed that indicated. The physical formula allows you to determine the maximum allowable value:
P = U * I, where
- P is power, measured in watts;
- U - voltage, unit of measurement - volts;
- I is the strength of the electric current, amperes.
That is, it is necessary to substitute known data into the formula: 220 V * 30 A. The result is 6600 watts. To convert to kilowatts, the resulting number must be divided by a thousand. Now it is clear that devices with a total power of no more than 6.6 kW can be powered from an automatic machine with a rated current of 30A.
With a known sum of consumer capacities, the nominal indicator of the protective device is determined. There may be several consumers in everyday life:
- six incandescent lamps of 100 watts;
- computer with a power of 500 W;
- boiler - 1.5 kW;
- TV power - 0.6 kW.
First, all values are reduced to one indicator: 600W, 500W, 1500W and 600W. Then the sum of the powers is found: 600 + 500 + 1500 + 600 = 3200 W. After that, the formula is applied and the rated current is calculated: 3200 W is divided by 220 V, the result is 14.5 A. Considering the standard rated currents for single-phase circuit breakers in the ampere-kilowatt table, a suitable device has a rated current of 16A.
Production voltage and power
At manufacturing plants, amperes can be converted to kW in the same way as for a single-phase network. But for this, a different physical formula is used.
In this case, power is equal to the product of voltage, current, and the square root of three. If it is necessary to calculate the power that a protective automatic device of 40 A can withstand, it is necessary to substitute known numbers in the formula. In production, the standard voltage of the electrical network is 380 V:
P = 380 V * 40 A * root of 3, the result is 26 326 W.
After converting the values, it can be argued that a three-phase automatic machine with a rated current of 40 A withstands the total power of consumers equal to 26.3 kW.
With a known power, you can find out with what indicator of the current strength you need to purchase the machine. To do this, the power is divided by the product of voltage and the square root of three. The resulting number must be found in the tableif it is absent, the most suitable automaton is selected. If it is difficult to carry out calculations manually or there are no tabular values at hand, then you can use a calculator to convert amperes to kilowatts.
Physical formulas allow you to easily convert amperes to kilowatts and find out the power consumed by household appliances over a certain period of time. For production, these calculations are necessary in the selection of protective devices and the acquisition of new electrical mechanisms.
