# Xfmr



## orion1989 (Jul 27, 2017)

Hey guys, gonna have some hands on xfmr wiring as a part of a test. Just trying to prepare in all ways possible. Does anyone have an easy way of explaining just the working of a basic xfmr both 3phase and single phase? Maybe some real life videos to share/recommend. 
Thanks in advance!


----------



## Big John (May 23, 2010)

If you're really unsure, go to Home Depot and pick up a couple doorbell transformers for $25.

You can practice wiring them in series and parallel to see how the ratios effect voltage. 

Big transformers may look intimidating, but they work the exact same way. 
High voltage:Low voltage. 
3ø is nothing more than a group of three 1ø windings.


----------



## MechanicalDVR (Dec 29, 2007)




----------



## Bird dog (Oct 27, 2015)

What kind of test is this? Uglies book may help.


----------



## orion1989 (Jul 27, 2017)

Thank you for idea! I will try it out! All helps! 




Big John said:


> If you're really unsure, go to Home Depot and pick up a couple doorbell transformers for $25.
> 
> You can practice wiring them in series and parallel to see how the ratios effect voltage.
> 
> ...


----------



## orion1989 (Jul 27, 2017)

Thank you, I will watch the videos and get back to you! All helps! 




MechanicalDVR said:


>


----------



## orion1989 (Jul 27, 2017)

It is a test to get a job! I cannot use an uglies book, only my tools per a letter I received. 




Bird dog said:


> What kind of test is this? Uglies book may help.


----------



## MechanicalDVR (Dec 29, 2007)

orion1989 said:


> It is a test to get a job! I cannot use an uglies book, only my tools per a letter I received.


You can use the Ugly's book as a brief study guide.


----------



## orion1989 (Jul 27, 2017)

Just got it yesterday so I'll definitely use that. 




MechanicalDVR said:


> orion1989 said:
> 
> 
> > It is a test to get a job! I cannot use an uglies book, only my tools per a letter I received.
> ...


----------



## telsa (May 22, 2015)

An EE can spend a FULL YEAR studying up on transformers.

There are A LOT of complications at that level.

But you don't.

The short list:

Transformers are -- mathematically -- identical to motor loads. Yup.

They really, really are.

At one level of abstraction, think of them as motor-generator sets -- that have no moving parts.

Current goes in -- is transformed into a MAGNETIC CURRENT -- and the magnetic current is transformed to a different voltage, different amps -- with losses due to this or that -- that show up as heat.

Stepping UP and stepping down are -- mathematically -- identical processes.

The real world issues turn on the physical properties of conductors, insulation, and ferrous cores.

At 50 to 60 Hertz ALL transformers use iron cores. These are the transformers that will show up on your tests,,, and in the field.

&&&&&&&&&

Our industry is QUANTIZED. We don't design for every possible physical scheme.

Read Ugly's for the NEMA standard, quantized, dry-type transformers.

Any transformer can be built, but if it's not a NEMA standard, the price will ROCKET to the Moon.

Our industry is so standardized, so quantized, that we -- as a practical matter -- take our answers from TABLES... like the ones in Ugly's.

For 3-phase 480 to 208Y120 dry-type transformers, the most popular size is 75kVA. It supports a 200-225 panel board. 

The next bump down is 45kVA. It supports a 100-125 panel board. 

And so forth.

Small transformers are used for CONTROL. 

Tiny transformers are used for door bells and every trivial low voltage application. ( wall warts )

Ultimately, Watts are Watts.


----------



## Bird dog (Oct 27, 2015)

Learn how to wire standard power xfmrs, buckboost xfmrs, & control xfmrs generally speaking. There may be certain types or configurations that are specific for your area.


----------



## orion1989 (Jul 27, 2017)

Thanks for so much info, I like that! Give me some time to take all that in! 




telsa said:


> An EE can spend a FULL YEAR studying up on transformers.
> 
> There are A LOT of complications at that level.
> 
> ...


----------



## orion1989 (Jul 27, 2017)

Working on that now, thank you and please share any more info you can think of! 




Bird dog said:


> Learn how to wire standard power xfmrs, buckboost xfmrs, & control xfmrs generally speaking. There may be certain types or configurations that are specific for your area.


----------

