Electric Power Generation Terms

Three major electric power generation terms you need to understand.

Here you will explore Alternating Current AC electrical frequency, voltage (or electrical potential), and current (electrical flow).

I will try my best to explain these concepts to beginners and provide links to further resources online.

On this website I want to help beginners understand the basics of electric power generation.

Voltage

When you think about voltage, think of it as electrical potential or electrical pressure differential.

Voltage is the force that causes electricity to flow, much like pressure causes water or air to flow.

Common voltages are 110/120 and 220/240, with 120V 60Hz being the common household voltage in North America and 240V – 60Hz being common for your clothes dryer and electric stove.

The rest or the world commonly sees 220V – 50Hz

I talk about more advanced topics on a different page, but these are all 1-phase voltages.  In industry you comonly have 3-phase power with common voltages being:

•  208V 3 phase.  This allows you to run 230V 3 phase electrical equipment AND have 120V 1 phase available as well
• 480V 3 phase is a common voltage in industry, mining, and emergency backup generators
• 600V is a newer 3 phase voltage used in industry.  The main benefit is that it allows you to use smaller diameter cables and save on copper costs.

When I was first leaning about electricity, I really found it helpful to think of voltage in terms of something physical. Pretending that electrical voltage is the same as the pressure water or air in a tank helped a lot.

Imagine you have two tanks at different pressure and they are connected with a pipe with a closed valve.  You have a pressure difference between the two tanks, which is similar to having a voltage difference between two electrical cables

If you open the valve, you will have have a flow of air or water from one tank to another.

But we are talking about electricity now – so imagine you have two wires at different voltages (electrical potential – electrical pressure).

If you close the switch or contact, then electricity is free to flow from one wire to the other.

For another perspective, visit the Wikipedia Voltage page.

Alternating current electrical frequency

If you already understand alternating current, then this is an easy concept.

The voltage that comes from an outlet in your wall is not a single, stead signal.

In fact, the direction of flow is always changing.  In North America it completes 60 cycles per second. This means that the direction of electrical flow changes 120 times per second.

An AC voltage signal appears as a sine wave.  For a good, complete tutorial, you should visit the Wikipedia Frequency page.

Current

If you close the contact between two electrical lines that have a voltage different, then you will have a flow of electricity.

The amount of electricity that flows is called the current.  This is the flow rate of electricity.  If you are coming from a mechanical background then imagine that current is like cfm of air or GPM of water.

As with voltage and frequency above, I am going to direct you to the Wikipedia Current page.

As you have probably heard, it is typically the electrical current that can make electricity dangerous.

Voltage causes the flow, but it’s the amount of electrical flow that causes damage to you.

Power Factor

Power factor is a more complex concept in electric power generation and I will explain it in a more in depth and technical format later.

A simple definition is “Power Factor is a measure of how much the current wave leads or lags the voltage”.

Power factor is entirely dependent on the load characteristics of your electrical system,

You already know that in an alternating current system (AC), the voltage and current signals form a sine wave.  You also know that the frequency of this sine wave is typically 50 or 60 Hertz – meaning the pattern repeats 50 or 60 times per second.

Well some of the components in your electrical system can cause the current wave to lead in front of, or lag behind the voltage signal.

A leading power factor can be caused by capacitors or some motors.

A lagging power factor can be caused by inductance in the system.

In the case that the current wave directly lines up with the voltage wave, this is referred to as a unity power factor (pf = 1).

A unity power factor is typical or a pure restrictive load (heaters) or most lighting circuits.

Power factor is a very important concept to understand once you get further in understand electric power generation.

I hope that this article has helped you to better understand some electric power generation terms.

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