When holding an electrical appliance, you will see the word capacity. So what is it? What types does it have? How to calculate? Those three questions will be answered by Vietts in turn in this article, you can read and refer to it.
What is capacity?
The capacity of this scrap press is, of this blender is… In life, we often hear a lot about capacity, but what it is, very few people can define. In Latin, Potestas means power. It is a quantity and tells humans the work done from ΔW, the transformation energy ΔE. They are determined for a specified time period T. T = t.
According to this formula, the power will be denoted by P.
Power is a word that is used a lot in industry and in everyday life. It is used when talking about machines, equipment, and engines that have a change in energy in a certain period of time.
We can take an example to make it easy to understand: The transformation from electricity to light in 1 hour (60 minutes).
The formula for calculating capacity that we often apply is as follows:
volumetric power formula
Power is measured in what unit?
Electricity capacity will be calculated according to the formula and applied the scale according to the international measurement system. The unit of measurement for electrical power will be Watt, abbreviated as W. The unit of measure is named after Jame Watt.
The advantage is: This unit we are most likely to encounter, especially on electrical equipment, electronics, lights, speakers, generators.
1 Watt will be equivalent to 1 J/s.
In addition, the prefixes added to this unit are also used to measure larger and smaller powers.
For example:
+ mW (milli watt) to measure smaller power.
+ MW (mega Watt) for larger power measurement.
Another unit that specializes in measuring power that we often encounter is horsepower. It also refers to engine power. Its abbreviation is HP.
And 1 HP is equivalent to 0.746 kW in the UK. In France, 1 HP is equivalent to 0.736 kW.
In the power transmission of the electricity industry, the commonly used unit of power measurement is KVA , the full name is kilo Volt Ampere. One KVA is equivalent to 1000 VA.
Types of capacity
Mechanical power
It represents the value of power used for mechanical machines, generally devices that operate on mechanical energy. And it will provide kinetic energy for other devices to operate.
Mechanical power will be divided into 2 cases.
In uniform motion
Time Δt, distance ΔS, moving the device with speed V under the action of a force F, the power will be calculated by the formula:
mechanical power in uniform motion
In rotary motion
Rotation angle Δφ, time Δt, angular velocity ω under the action of torque M, the power will be calculated by the formula:
mechanical power in rotary motion
Power capacity
To calculate instantaneous electrical power, one will use the following formula: p(t) = u(t).i(t)
where u is the instantaneous value of the potential difference
i are the instantaneous values of the amperage.
In the case, u and i are constant in time, meaning that at that time current constant we have the formula P = U.I.
For the commonly used alternating current , there are three types: effective power P, apparent S, impedance Q. We have the formula: S = P + iQ
Note: i: imaginary number unit
Or the formula: S2 = P2 + Q2
Some other types of capacity
Apparent power
It is called apparent power because it is the total power. The parameter will indicate the power supply from the power supply. Or more specifically, it is the sum of the real active power and the imaginary part of the reactive power in the alternating current.
Speaker power
Speaker power is often encountered on labels affixed on speaker equipment, amly. We can understand that is one of the important parameters, letting users know the volume of the speaker when working. This parameter is measured in Watt (W).
Rated power
Nominal power may sound strange, but in reality is it real or rated power. Even with the name of the date, it is also the parameter recorded on the products of the UPS. Through the rated capacity, the user can grasp the maximum value that the UPS can meet when the power is supplied to the external circuit.
Power Booster
It is a device, a component that appears in the sound system. This power amplifier is responsible for amplifying the audio signal so that it can be pushed to the listener’s ear.
Cooling capacity
Refrigeration capacity is a concept that represents the capacity or cooling capacity of electrical appliances in the house, namely air conditioners. Cooling capacity is measured in units of Btu/h. Through this number, we can know is the level of electricity consumption of the air conditioner.
Set capacity
Power set is the total rated capacity of power consuming devices in the network. The customer also needs to be careful as this is not the actual capacity that needs to be provided.
Those are the powers most commonly encountered in our daily lives.
Formula for calculating power consumption
Why calculate power consumption?
When most manufacturers publicly and specifically state the operating capacity on the labels of equipment, including household and electronic appliances, etc. However, calculating this capacity will help to know the average. electricity consumption in the year, in the quarter, know the amount of electricity payment. From there, a plan to use electricity appropriately and economically will be made and implemented.
The formula for calculating power consumption is as follows: A = P x t
With this formula, we need the following parameters:
+ A is the amount of electricity consumed, the unit is KWh.
+ P and symbol of power consumption. Its unit is KW.
+ t: Is the time of use, the unit is hours (h).
After getting the calculation results, proceed to convert to the most common units. The way to convert to W is as follows:
1KW = 1000W
1MW = 1,000,000W
If the air conditioner has a capacity of 120W, it is equivalent to 0.12KW and works in a day with 24 hours. The power consumption of the cabinet is 0.12 x 24 = 2.88 (KWh).
The higher the capacity, the higher the power consumption.
Formula to calculate 3 phase electrical capacity
Three-phase electricity is an electric current with a large capacity and power consumption. The number of V specified in each country is different, in Vietnam, the 3-phase line will have a voltage of 360V.
Compared with 220V or 24V, 1-phase lines, this 3-phase line has a higher cost. That is why it is preferred for use in industrial machinery, motorized machinery, mining machines such as car washing machines, industrial sewing machines, presses, industrial washing machines, etc.
3-phase power capacity is specifically calculated through the formula: P = (U1 x I1 + U2 x I2 + U3I3) x H
In this formula we have:
U is voltage, its unit is V
H is time, units are hours (h), minutes (m).
I is the amperage, in Amperes (A)
In addition, we can apply another formula that is: P = U x I x cosφ
So what is Cosφ? It is the power factor per working load.
How to see wattage on electrical equipment
On current electrical, electronic or household appliances, and refrigeration equipment, manufacturers must record power consumption parameters. This is a mandatory requirement to help consumers refer to and consider how much power is consumed in an hour to choose the correct one, serving the needs of work and production.
This is also a parameter that allows companies to compete with each other to offer good equipment with small power consumption. Since then, the equipment has an increasingly high use value, the market is more diverse and there are more choices for buyers.
To see the power value of an electronic device these days is also quite simple, not as complicated as we think. Each device has a label, with a data sheet attached. It can be expressed as power consumption, input power, device capacity… Customers should read the parameters carefully, have questions, contact technical staff for answers.
Some capacity of commonly used household electricity
To be able to choose or use electrical equipment effectively, users need to refer to a number of device capacities offered by manufacturers:
+ Electric rice cooker: The pot with a capacity of 1.2 liters has a capacity of about 350-400W.
Refrigerator: The cabinet has a capacity of about 120-150 liters with a capacity of about 80W.
+ Fan: The device has a capacity of about 40-120W.
+ TV
