> groups.google.ca

> In article
> <22f6648f-0997-460f-acb1-716c8a652bdd@c65g2000hsa.googlegroups.com>,
> ssylee gmail.com> wrote:
>

>> groups.google.ca

>
> What in the world is a Three-phase transformer phasor clock diagram?"

> It refers to a "standard" phase shift for star delta transformers. As I
> recall, the standard is that primary A phase leads secondary A phase by 30
> degrees. The way that the A phase as indicated on a drawing is not really
> that important- as long as it is marked -but there is likely a standard.
>
> It is related to field wiring applications. If everyone does it this way,
> there is less likelihood of misconnection, particularly for some protective
> relaying.

> In article <4scQj.91369$Cj7.801@pd7urf2no>, "Don Kelly"
> wrote:
>

>> It refers to a "standard" phase shift for star delta transformers. As I
>> recall, the standard is that primary A phase leads secondary A phase by
>> 30
>> degrees. The way that the A phase as indicated on a drawing is not really
>> that important- as long as it is marked -but there is likely a standard.
>>
>> It is related to field wiring applications. If everyone does it this way,
>> there is less likelihood of misconnection, particularly for some
>> protective
>> relaying.

>
> It sounds like one of those coo-book things that are needed only if you
> do not understand what is going on, I prefer working with fundamental
> principles rather than recipes. ...

> ----------------------------
> "Salmon Egg" sbcglobal.net> wrote in message
> news:SalmonEgg-56ABF8.13011725042008@news.la.sbcglobal.net...

>> In article <4scQj.91369$Cj7.801@pd7urf2no>, "Don Kelly"
>> wrote:
>>

>>> It refers to a "standard" phase shift for star delta transformers. As I
>>> recall, the standard is that primary A phase leads secondary A phase by
>>> 30
>>> degrees. The way that the A phase as indicated on a drawing is not
>>> really
>>> that important- as long as it is marked -but there is likely a standard.
>>>
>>> It is related to field wiring applications. If everyone does it this
>>> way,
>>> there is less likelihood of misconnection, particularly for some
>>> protective
>>> relaying. ...

> "Don Kelly" wrote in message
>
> news:GezQj.92135$rd2.11586@pd7urf3no...
>
>
>

>> ----------------------------
>> "Salmon Egg" sbcglobal.net> wrote in message
>>news:SalmonEgg-56ABF8.13011725042008@news.la.sbcglobal.net...

>>> In article <4scQj.91369$Cj7.801@pd7urf2no>, "Don Kelly"
>>> wrote:

>

>>>> It refers to a "standard" phase shift for star delta transformers. As I
>>>> recall, the standard is that primary A phase leads secondary A phase by
>>>> 30
>>>> degrees. The way that the A phase as indicated on a drawing is not
>>>> really
>>>> that important- as long as it is marked -but there is likely a standard. ...

> Sure, one can connect in such a way that the secondary a,b,c phase voltages
> lag or lead primary A,B,C by a number of different angles. However, life is
> a lot easier if a single standard is used, within a utility and between
> utilities and manufacturers. It can eliminate a lot of expensive mistakes.
> It is not a lack of knowledge of what is going on but rather a knowledge of
> what possible phasing problems (in differential protection for example or
> even fault analysis) can occur that leads to setting a standard. --

> In article ,
> "Don Kelly" wrote:
>

>> Sure, one can connect in such a way that the secondary a,b,c phase
>> voltages
>> lag or lead primary A,B,C by a number of different angles. However, life
>> is
>> a lot easier if a single standard is used, within a utility and between
>> utilities and manufacturers. It can eliminate a lot of expensive
>> mistakes.
>> It is not a lack of knowledge of what is going on but rather a knowledge
>> of
>> what possible phasing problems (in differential protection for example or
>> even fault analysis) can occur that leads to setting a standard. --

>
> I am in a situation where (aside from being retired) I have little use
> for my PE license. Most of my need for a license has been to use the ...

> ----------------------------
> "Salmon Egg" sbcglobal.net> wrote in message
> news:SalmonEgg-465681.17292126042008@news.la.sbcglobal.net...

>> In article ,
>> "Don Kelly" wrote:
>>

>>> Sure, one can connect in such a way that the secondary a,b,c phase
>>> voltages
>>> lag or lead primary A,B,C by a number of different angles. However, life
>>> is
>>> a lot easier if a single standard is used, within a utility and between
>>> utilities and manufacturers. It can eliminate a lot of expensive
>>> mistakes.
>>> It is not a lack of knowledge of what is going on but rather a knowledge
>>> of
>>> what possible phasing problems (in differential protection for example
>>> or
>>> even fault analysis) can occur that leads to setting a standard. -- ...