Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
Now this I agree, I hate imperial measurement. Metric would be SO much easier.
208V to 230V buck boost
- Thread starter cppoly
- Start date
Huh, I have a full understanding of these type of transformers, and I DO refer to the as Buck/Boost transformers , so I kind of take offense at your characterization. If I wanted to be snooty, then I would say, it is an autotransformer, not either a buck or a boost, because when you buy one it is usually a 12/24 to 120/240 transformer. Just sayin'
I refer to them as Buck/Boost transformers also.
Just saying you're not going to be using them for both at the same time.
You're either going to be Bucking or Boosting, not both for the application.
Jap>
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
The answer is because there really is no such thing a s "24V" coil. It is technically a coil that has an insulation rating that can withstand xxx number of volts. The transformers we are all talking about are basically a bunch of windings around a core, each one is independent. and you then select the in and out leads of each coil and hook some coils up in series and/or some coils up in parallel to achieve the end results you want.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
For those that care, the conversion formula is:
Boost % = (HV-LV)/HV
Buck % = (HV-LV)/LV
The typical individual transformer coils are either 120:12, 120:16, or 120:18. There are usually two sets of coils yielding 240:24, 240:32, and 240:36 or roughly a 10%, 13.3% and 15% change based on 240V for the HV.
Boost % = (HV-LV)/HV
Buck % = (HV-LV)/LV
The typical individual transformer coils are either 120:12, 120:16, or 120:18. There are usually two sets of coils yielding 240:24, 240:32, and 240:36 or roughly a 10%, 13.3% and 15% change based on 240V for the HV.
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Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
One thing I like to mention whenever talking about these is. Don't use them for voltage drop correction if you have variable va loads. If your load goes up and down it does so in series with the wiring and can produce undesirable high and low voltages. Not trying to get in to the theory of it, just be aware.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
As I mentioned previously, as a practical matter you will take a conventional 240V:24V (or 240V:32V, or whatever) transformer and _wire it_ into an autotransformer configuration. The big reason to use multiple coils connected together as a single coil is that some parts of the coil carry more current than other parts, so you want different size wire.
See this diagram:
The transformer is built with 4 separate coils, all wound on the same core. By connecting the appropriate jumpers it gets configured as a boost transformer.
-Jonathan
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
You are showing a single tapped autotransformer, which is not typical for buck-boost arrangements.
Buck-boost are usually field configurations of a standard two winding transformer.
Thank you kindly, sir! I'm just a grumpy old git, nearly eighty so, when I was at secondary school they still used Imperial units. I still used that for old variable speed drives.
Carultch
Senior Member
- Location
- Massachusetts
It's much more likely to survive an accidental shock from 120V than from 240V, so the majority of residential circuits are 120V connected line-to-neutral. It also comes from the history of Edison's attempt at using 3-wire bipolar DC power to supply homes, that didn't stand the test of time, so split-phase is also sometimes called a 3-wire Edison system. The choice of which line to use is staggered, in order to balance the lines on the service as much as practical. It's rare that 1500VA is insufficient for a receptacle load, so 120V is good enough in most cases. Electric kettles could benefit from a 240V supply, but most other loads don't need it.
The big ticket loads (A/C, ovens, electric dryers, etc.) that need a lot more power, are connected across the two lines (240V) or across two phases (208V). And even bigger ticket loads in commercial applications, are powered by all 3 phases. A lot of these loads are hard-wired, rather than plug and receptacle, so it's much less likely that a person will accidentally touch these circuits. When there is a need for a 240V receptacle, it has a special shape to prevent standard plugs from connecting.
I appreciate that. We do have pretty good receptacles to ensure that risks are not compromised and each of those sockets have individual fuses.
.Seems to be one of your favorite topics. We have 120 volts. Edison invented a 3 wire system that doubled the voltage to 240 volts while also providing 120 volts. Then a 3 phase system that still provides 120 volts will, by the laws of physics, produce 208 volts phase-to-phase. There is no confusion here. Everything starts at 120 volts and is built around that. Sometimes that means ending up with a weird number like 208. We just deal with it and don't spend too much time whining about it.
Double it if you want to. We don't need to to do so.
I wasn't suggesting that you should.
And we keep it simple.
Yeah. You're definitely simple.