When you choose to select a solar panel system for your property, you can be exposed to a lot of unfamiliar electrical knowledge, including the physical quantities in various electrical calculations and the conversion formulas between them. However, more and more people are taking the initiative to learn this electrical knowledge out of the requirement to install a solar panel system. This article is going to cover two common physical quantities used in electrical calculations: amperage (A) and volt-amperes (VA), and how to convert between them.
In fact, the formula for calculating solar panel systems is not complicated, but in order to learn the formula for converting amperes to volts, we first need to recognize the following physical quantities.
1. What is an Ampere (A)?
An ampere is the basic unit of current in the International System of Units, abbreviated as ampere and symbolized as A. It is often used to describe the amount of charge that passes through a section of an electrical circuit in an instant, and it can also be thought of as describing the amount of speed at which a current passes through a section of a circuit.
2. What is a volt (V)?
The volt is a unit of voltage, abbreviated as V, and symbolized as V. It is often used to describe the amount of charge passing through a section of a circuit at the same time, and can be used to indicate the amount of “power” of the current in the circuit. The greater the value of the volt, the greater the force of the current in the circuit, and conversely, the smaller the value of the volt, the less the force of the current in the circuit.
Volt can also be used to measure a unit of electrons in the electric field due to the different TV produced by the unit of energy difference, the size of its value is equal to a unit of positive charge due to the electric field force from one end of the circuit to move to the other end of the amount of work required to be done, which shows that the volt can also be the unit of potential energy. When used as a unit of potential energy, a decreasing value indicates that the electric field force is doing positive work in moving the charge. Increase in value, that the electric field force in the process of charge movement to do negative work.
3. What is the volt-ampere (VA)?
The volt-ampere is a unit obtained by multiplying one unit of volt by one unit of ampere. In DC circuits, it is the unit of power (P), meaning the same as watts (w).
In AC circuits, it is the unit of apparent power. It is important to note that apparent power (S) in an AC circuit is not the same as real power. Since power does not remain customized in AC circuits, the presence of apparent power is a simplified representation of the rated power, and its magnitude indicates the minimum power required to operate the appliance. Therefore, when using an AC circuit to supply power to an appliance, the apparent power rating is a very important reference value, and the power of the power supply must be greater than the apparent power of the appliance as a means of minimizing the appearance of power surges during the supply process and avoiding damage to the appliance.
4. How to realize the calculation from amperes to volt-amperes?
After learning the units of measurement of the physical quantities mentioned above, we can begin to learn the formula for converting amperes to volt-amperes. Since the meaning of Volts Amps is not the same in AC and DC circuits, the conversion formulas used in the two different types of circuits are explained separately below.
DC Circuits
Although the Ampere and the Volt-Amp are both basic units of electrical knowledge, they do not measure the same physical quantities in DC circuits: the Ampere is the physical quantity of current, while the Volt-Amp is the physical quantity of power. In order to convert the two, we need to introduce an intermediate physical quantity, the volt (V). From this, the conversion can be realized by the following equation:
P (VA) = I (A) x V (v)
The p in the above formula is the power in the DC circuit, I is the current in the DC circuit, and V is the voltage in the DC circuit.
In order for you to better understand and grasp the above formula, examples of applications are given below. When you want to install a solar panel system for your property, and you know that the household supply voltage is 110v, and your appliances run at a total current of 20A, you need to install solar panels rated at 20A x 110v = 2200w.
AC Circuits
After you have understood and mastered the simpler DC circuit conversion formulas, you will be introduced to the AC circuit ampere to volt-ampere conversion formulas below. In fact, AC circuits are used far more frequently than DC circuits in practical applications, and the power supply for the most common appliances in our daily lives is realized through AC circuits. Including the DC power from the solar panel system also needs to be converted to AC power by an inverter before powering the equipment.
There are two types of AC power: single-phase AC power and three-phase AC power. For single-phase alternating current, the conversion formula is as follows:
S (VA) = I (A) × V (v)
It is worth noting that S in the above formula refers to the apparent power in a single-phase AC circuit, I refers to the current in a single-phase AC circuit, and V refers to the voltage in a single-phase AC circuit.
As for three-phase AC, there are two algorithms for its specific conversion formula, which are:
Calculate using the voltage across the line (V L-L):
S (VA) = √ 3 × I (A) × V L-L (v)
and, calculation using line-to-neutral voltage (V L-N):
S (VA) = 3 × I (A) × V L-N (v)
