Close the Loop on Power!

Volts, amps, watts, kilowatts, and power. I don’t know about you, but until today, nothing has earned my ire and frustration quite as much as trying to clearly understand the difference between these electrical terms once and for all: volts, amps, watts, kilowatts, and power. They’re all to do with electricity, but what exactly do they each mean, and how do they all fit together? Today is the day for closing this loop!

A practical example involving all of these terms makes it easy to grasp them. Let’s say we have a motor with a dual rating of 230V/460V. Will running a motor at its higher voltage rating save money by using less amperage?

It won’t because we pay for power in watts or kilowatts. Volts are units measuring electrical potential, while amps are a unit of measurement for electrical current. Power is the combined value of amps (electrical current) and volts (electrical potential), and it turns out be the same for each “rated value” (meaning the 230V or 460V voltage values rated to the motor on its nameplate). Power, which is (amps * volts) is measured in watts or kilowatts.

So, for example, if we’ve got:

*14 amps run at 230V, (14 * 230) that’s 3,220 watts, or 3.2 kw of power

*7 amps run at 460V (7*460) is also 3,220 watts, or 3.2 kw of power

What’s interesting to note is that the higher voltage rated value of 460V is double that of the lower value of 230V. It takes half the amps (i.e., running electrical current) to get the same power (measured in watts or kilowatts) with 460V (of electrical potential) to attain 3.2 kw of power.

Running current at the higher rating can only save money on installation costs because smaller diameter wires can be run at the higher rating than are required for the lower rating.

This explanation, which I was lucky enough to stumble on in web research, finally had each term making clear sense, while showing how it all fits together in practical terms.

This is the source article via El Paso Electric: http://c03.apogee.net/contentplayer/?coursetype=md&utilityid=elpaso&id=12592

 

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