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HVAC School - For Techs, By Techs

Single Phase, 3 Phase, and Split Phase Explained

HVAC School - For Techs, By Techs

Bryan Orr

Training, Careers, Airconditioning, Self-improvement, Hvac, Business, Education, Refrigeration, Heating, Ac, Apprenticeship

4.8985 Ratings

🗓️ 22 December 2017

⏱️ 42 minutes

🧾️ Download transcript

Summary

In this podcast episode, we discuss power distribution and some practical tips about three-phase, single-phase, and split-phase power.

The power company generates three-phase power; a power pole transformer typically has three current-carrying conductors. Each phase of power runs at 60 Hz and generates a sine wave. That sine wave peaks and valleys in a wavy formation. Power is generated in a rotating magnetic field, so it is helpful to think of a sine wave as a variation of a circle.

Transformers take high voltage and bring it down to 120V split-phase via a winding on the left, a winding on the right, and a neutral tap. The split sine waves are exactly 180 degrees out of phase; they are direct opposites, and they will intersect and both be "off" at the same time. The center is neutral. This 120V split-phase power results in 240V total; therefore, we can use them in 240V applications. Split single-phase motors require a capacitor.

Three-phase power uses all three legs of power, and the sine waves are 120 degrees out of phase with each other. In three-phase power, only one wave will be "off" at any point in time. Three-phase power is a more efficient means of running motors; split single-phase power is relatively inefficient and requires a capacitor. However, reverse-phasing is a possibility and may run motors backward, causing damage. The most common type of three-phase transformer uses the wye configuration and works for 208V applications.

Bryan also discusses:

  • Wye vs. delta configuration
  • Delta configuration high leg
  • Start assistance and capacitors
  • Residential vs. commercial applications
  • Capacitor failure
  • 277V and 480V applications
  • Replacing single-phase with three-phase power or vice versa
  • Three-phase condensers with single-phase air handlers

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Transcript

Click on a timestamp to play from that location

0:00.0

This episode of the HVAC School Podcast is made possible because of generous support from our sponsors,

0:15.7

Rector Seal, Testo, Carrier, and Mitsubishi.

0:21.0

And one thing that I want to mention quickly about Mitsubishi is that we've dealt Mitsubishi.

0:25.0

I guess it's been since about 2009. We started our business in 2005 and I actually drove up to Asheville, North Carolina to take a class in order to become a Mitsubishi

0:36.0

diamond dealer.

0:37.7

And since that time we've sold just thousands of Mitsubishickless systems and we really like how sturdy they are, how they

0:45.9

hold up.

0:47.4

And one thing that's kind of nice in having both Rector Seal and Testo and Mitsubishi Duckless as sponsors of the podcast is that the three of those

0:57.6

brands really converge a lot for us day to day when we're testing and cleaning and installing

1:04.0

duckless systems because we use the rector seal

1:07.2

dissolve kit in order to get the evaporator coils on

1:09.9

ductless systems really clean when we need to do a really

1:11.9

thorough cleaning of the unit in place.

1:14.5

We can do that with the Rector Seal Dissolve Kit.

1:17.4

For testing Mitsubishi-Duckler systems, we use the Testo 605 eyes, as well as the Testo Smart Probes when we have to connect to the

1:24.7

actual refrigerant lines. We don't want to use a regular gauge manifold and

1:28.6

potentially lose even a few ounces of charge, so we use the Testo Smart Probes to connect so we use the testo smart probes to connect and we use the

1:34.7

testo 605 eyes to actually verify delivered capacity on the unit and all in

1:40.3

all Mitsubishi rector seal Testo have been great partners.

1:44.6

If you want to know more about how we do a duckless cleaning, a duckless maintenance,

1:49.3

we actually just put up a video just a few days ago, actually, last week, on our our YouTube channel if you go to the

1:54.6

HVAC school YouTube channel you can find that video there of us using the

...

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