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The straightforward answer is 32v. Course dismissed.

You are watching: Can i use 208v instead of 240v

I’m just joking, the course. Detect the difference in between 208 and 240v power supplies might sound quite simple, however there are some nice sharp an essential differences.

Apart from the obvious differences in as whole voltage, 208 and 240v power offers use the electric company’s power differently. The motors likewise see entirely various sine waveforms. The potential throughout these waveforms varies, i m sorry is where we acquire the different voltages from. We likewise tend to usage 240v strength in residential applications, when we use 208v in irradiate commercial applications.

This article will go over the differences between single or split-phase 240v motors and 208v ones. The will additionally discuss the applications that each power source form and why it may not be a great idea to usage 208v motors for 240v applications.

Visualizing voltage

Before we dive into the differences in between voltage types, us should most likely talk around how we visualize voltage and also how the relates to engine movement.

As you know, electrical motors rotate in a circular motion. Us don’t view the corresponding voltage together a circle, though. Us visualize and also map voltage trends as sines, which room wavy lines that rise and also fall in ~ a regular rate ~ above a chart. 

A sine tide takes the rotation the a one (in degrees) and also compares it come unit time. Look at the snapshot below.

As you have the right to see, the sine tide “rolls out” the one by plot the alters in its degrees as time progresses. Once the engine rotates 30° indigenous a beginning point of 0°, you can see that rise on the sinusoidal waveform. The sine tide peaks at 90°, as that’s the highest point on the rotation. It likewise bottoms out at 270°, i beg your pardon is the lowest point. You can see every one of those ~ above the left circle. 

Each strength leg has its own sinusoidal waveform, and that’s whereby you will see the differences between 240v single-phase motors and 208v motors.

240v single-phase and also split-phase

We periodically use the state single-phase and split-phase interchangeably, and also it can be confusing. Back they approximately mean the exact same thing, castle sound contradictory, so we’ll describe the names.

“Phase” refers to the usage of the initial power native the utility. The power agency offers three legs of power, for this reason a single-phase mechanism only derives its power from one of those legs.

We also refer to single-phase strength as split-phase power since the single-phase strength can separation into two separate, the contrary phases. If girlfriend look at a waveform, you’ll an alert three lines: 2 opposite sines and one level line. The flat line is the facility tap, and also the sines space the break-up phases. 

The split phases are 180° directly out of step and always have straight opposing values. If you think about our previously circle, 90° and also 270° space 180° personally from every other, and they room the peak and also trough the the wave, respectively. Therefore, once one the those separation phases will its highest point, the various other phase will certainly bottom out. However, lock cross when they with the zero allude (on the facility tap). That’s because 0° and also 180° space on the exact same horizontal line in a circle. You deserve to see every one of this in activity below.

Single- and also split-phase electric motors are typically 240v or 230v. Some split-phase strength sources might be 220v, 120v, 115v, and also so on, yet higher-voltage applications are more common nowadays. You’ll probably see 240v the many often, yet you might see part even higher voltages, choose 245v or 246v.

So, wherein does the 208v come in?

As you can probably assume, power resources with 208 volts room NOT yes, really single-phase. They require two foot of power from the strength utility, conversely, 240v motors and also appliances only use one.

You will frequently see 208v present in three-phase buildings when “single-phase” equipment (like one A/C condenser) is wired to two legs that three-phase wye power. 

Here’s whereby some civilization get confused: if a split-phase motor splits a solitary power resource into 2 120v phases, climate shouldn’t a motor that offers two legs of three-phase power also equal 240v?

No, and here’s why:

Remember when I stated that the sine tide of split-phase motors are 180° out of phase? The power legs that 208v motors are in reality 120° the end of phase. The distance in between the sine waves isn’t completely opposite. They can not reach their complete potential if lock don’t straight oppose each other, and the voltage is lower overall as a result. 

You can particularly see this once you look at a graph. The sine tide look more like lock wind roughly each other, no cross end a fixed center point. The maximum potential between the points is lower overall. You deserve to see this in the photo below.

Can you usage 208v motors instead of 230v/240v?

You may an alert that part single-phase electric motors are rated because that 208/230v. So, it may seem like the motor will find ways to comprise for the lower voltage. That’s not quite just how these motors work. You’ll view some differences in power if you use a 230v motor because that a 208v application, even if the rated for both.

You can’t suppose the same level of performance when you use 208v ~ above 230v (or higher) applications. For example, when you use a 208v engine in a residential condensing unit that generally requires 230v, the unit won’t operation at its full capacity.

Some people say that you can expect a higher current as soon as you usage 208v in ar of 230v, but that’s quite rare. The motors don’t magically comprise in present what is shed in voltage, even if it could make sense to see greater current native the rated watt or horsepower. Instead, as soon as a typical 208/230v engine is associated to 208v, it usually slips an ext and operation at a reduced output 보다 on 230v or 240v. That results in lower wattage supplied at a reduced efficiency, which adds up to few BTUs produced.

208/230v motors additionally have a more tough time beginning up, and also they may create a problem voltage drop much more often when linked to 208v. Voltage drop normally isn’t an issue for split-phase 240v systems. However, ~ above 208v, the motors start v a lower voltage. Therefore, the exact same amount of drop will have actually a greater impact on the system.

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In short, just because a 208v motor might be design to operation on 230v or 240v solution by using 2 power foot from the energy source, that doesn’t mean that the will provide the exact same output efficiency.  You will see distinctions in power if you shot to usage 208v once 240v is commonly required.