Introduction
Hello and welcome to another blog, Here I have explained the purpose of electrical power because I got questions about this topic at my interview?
As a fresher, I got this question, "what is the formula for single-phase and three-phase power supply?"
Electrical formula
An Electrical formula has the purpose of solving many practical problems by calculation. Depending on the problem, electrical formulas can have different configurations, always basing on the problem. I have endeavoured to collect many formulas which can be brought forward to demonstrate.
Basic Electrical Formulas on power
Basic Electrical Formulas are starting with power. The electrical power formula helps in power analysis and required power calculation ie., it helps in the analysis of power transmission in KW and power required to operate the load. (You will get full information after derivation)
The unit of power is Watts and symbolized by the letter W or KW(Kilowatt)
Power is the word representing Electrical Energy which is nothing but the combination of Voltage and Current. So the formula can be written as
∴ P=V x I
P=Power V=Voltage I=Current
Now its become easy for us to derive voltage and current using the formula, power
∴ V=P/I
∴ I=P/V
Now, Ohms Law explaining that the Potential difference between two points of the conductor (V) is directly proportional to the Voltage drop across the conductor (IR) at a constant temperature.
The potential difference is V, and the voltage drop is IR.
∴ V=IR
R=Resistor
Now Electrical power can be written as ∴ P= V^2/R
∴ P= I^2 x R
So, By the derivation of electrical power, we can conclude that Electrical power (P) has only 3 formulas
- P=VI
- P= V^2/R
- P= I^2 x R
My Interview Experience
1- Phase Power formula
Interviewer: "what is the formula for single-phase and three-phase power supply?"
Me: For a single-phase power supply, the formula will be P=V*I (Cos φ)"
Interviewer: What is Cos φ?
Me: Cos φ is the power factor, and the value is 0.8 which is constant.
3- Phase Power formula
Interviewer: What is the formula for the 3-phase power supply?
Me: For a three-phase power supply, the formula will be P=√3 * V * I (Cos φ)
Interviewer: What is the value of √3?
Me: The Value of √3 is 1.732
Here the main question will arise "Where does the square root(3) come from?"
Me:😀blurrrr