- Location
- New Jersey
- Occupation
- Journeyman Electrician
Just wondering is the common point on a WYE transformer called XO (ex-oh) or X0 (ex-zero)? Seems like X1,X2,X3 would make it the latter, X-zero.
Wye Transformer X0
- Thread starter infinity
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I have always considered it x-(zero). I believe x-(oh) is used for the same reason many people recite telephone numbers or any series of numbers containing a zero as "oh" instead of zero. They have lazy mouth. 
How about another question, Why "X". Why not "L" for low. "H" is for high, right? :?
How about another question, Why "X". Why not "L" for low. "H" is for high, right? :?
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
In symmetrical components, zero sequence is simplistically imbalance. Since the X0 is the grounded part of a wye, it handles imbalance.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Lazy American speech, or maybe lazy typesetters, typewriters, and poor penmanship.
In a similar vein the Square D breaker family was the Q4, the Q2, the Q1, and finally the famous Q-oh.
By the way, what about 'aught' wire sizes?
kwired
Electron manager
- Location
- NE Nebraska
Lazy American speech, or maybe lazy typesetters, typewriters, and poor penmanship.
In a similar vein the Square D breaker family was the Q4, the Q2, the Q1, and finally the famous Q-oh.
By the way, what about 'aught' wire sizes?
I'm pretty the O in QO is a letter and not a number. I think it stands for "Quick - Open" Which they boast they are quicker responding than most competetors - which they do seem to be most of the time.
John120/240
Senior Member
- Location
- Olathe, Kansas
I have a aught one Chevrolet truck. The economy went south in aught eight. QO is Q-oh as
stated by Kwired. XO in a transformer is X-oh. Aught is also a wire size.
stated by Kwired. XO in a transformer is X-oh. Aught is also a wire size.
kwired
Electron manager
- Location
- NE Nebraska
I think the X0 in a transrformer is a zero, not the letter O.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
My feeling as well since it fits in the scheme of X1, 2 and 3.
weressl
Esteemed Member
Perhaps if the European/English usage of 'null' were adapted instead of the confusing 0/O/o/'oh' we wouldn't be talking about this. The '/' mark across the oval/circle was also introduced, unfortunately it is not used or available in most typefaces and keyboards. (It would be a great change, but nothing short of an Act of God would be able to accomplish it.)
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
No, it absolutely does not stand for Quick-open.
Their original breaker family was the MO - which was called a Multi-open.
Then came the the XO breaker followed by the QO (Q1, Q2, and Q4). Finally we are at the HO family.
There is no doubt that it is called the Q-oh and is presently written with the letter O, I just wonder what it was intended to be, back in the late 50's, as every other Square D breaker at the time was a Letter-Number combination.
By the way, only the 15 & 20A, single pole QO breakers have the trademarked Qwik-Open mechanism.
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- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Take a look at the IEEE/ANSI standards for transformer nomenclature.
It, absolutely, positively, is written as X0.
The question is why we pronounce it as X-oh.
kwired
Electron manager
- Location
- NE Nebraska
You just mentioned the trademark "Quik-Open" yet can't see that is where the "QO" name comes from?
Only thing I had wrong in earlier post was spelling it "Quick-open".
As soon as you spelled it the way the trademark is spelled it jogged my memory - that is where the QO name comes from.
? Here is one from character map on most computers... Just curious to see to see if it posts. I use it in "word" and "excel" all the time.
?
(Just playing to see if it posts to forum)
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Read my lips IT DOES NOT.
After college my first job was Square D back in 78. My earliest catalog sheet is dated 1960, although I have Digests going back into the 30's.
Square D has used the letter Q to designate 240V circuit breakers since the late 50's. At the time of their introduction these breakers were the Q4 (400A max), the Q2 (225A max), the Q1 (100A max) and the QO (60A max). Their current generation of 240V breakers continues to use the letter Q.
kwired
Electron manager
- Location
- NE Nebraska
I don't know.I guess we need to know if there is any significance to the use of "Q". I suppose the 0, 1, 2, and 4 can be seen as progression of frame sizes.I think the Qwik Open mechanism was original to the QO line, maybe just a coindidence.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Maybe,
My guess is they called it a Qwik-Open mechanism because it was on a QO breaker.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
I agree entirely.
Computers can print 0 and O as different characters so this may become a thing of the past. The problem will always be with handwriting.
I started to use the null symbol (/) the second time I had to enter data onto punch cards.
Open Neutral
Senior Member
- Location
- Inside the Beltway
- Occupation
- Engineer
But here's the issue.... slashed zeros are a long standing norm in other fields, and that's no zero. To me, that's a phase...
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
I always thought XO was referring to the terminal we always assume is open.
Yea, it is to most in our field. I was thinking null set and empty set...
Maybe a lower theta?
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