Zero Sequence CT

[Besoeker]

I'm working with an engineer from GE; they design and build this equipment, he knows what I'm looking for and has a CT in mind for me to use. The guy was a real pleasure to speak with.

A guy claiming to be an EE once told me that a center tapped transformer ( like those serving homes ) is 2 phase power. Is that your belief?

A bit of a digression on that point.

It is mine - two supplies 180deg out of phase.but I think it is not generally what it is taken to mean in this forum.
I base my take on hexaphase transformers which is an arrangement used for high current low voltage rectifiers. This a transformer with a three phase centre tapped wye secondary. But it is never, in my experience, called three phase.

Two phase is generally refers to a Scott or Le Blanc arrangement.

 

[buffalonymann]

Well, technically not correct. An imbalance can still vectorally sum to zero, whereas a GF will not. So you are looking for current leaving the system, not looking for an imbalance.

Let us know how this works out. Always open to learning something new.

First, my CT encircles the circuit conductors, the only imbalance possible is ground fault - so says Kirchoff

 

[buffalonymann]

A bit of a digression on that point.

It is mine - two supplies 180deg out of phase.but I think it is not generally what it is taken to mean in this forum.
I base my take on hexaphase transformers which is an arrangement used for high current low voltage rectifiers. This a transformer with a three phase centre tapped wye secondary. But it is never, in my experience, called three phase.

Two phase is generally refers to a Scott or Le Blanc arrangement.

Could you explain how you arive at the idea it creates 2 supplies 180 degrees out of phase

 

[Ingenieur]

Look, I appreciate that you responded and I'm sure you have the skills to run wires in a mine, but this subject is simply not your forte.

I worked in industrial process for 25 years
mining 5
I don't run wires, I tell people like you how to
btw: gfp is gfp, regardless of location, electrons are the same lol
simmer down cupcake, doesn't sound like you have a clue

 

[gar]

180720-1522 EDT

What is the definition of a Zero Sequence CT? What makes a Zero Sequence CT different than a plain CT?

.

 

[Ingenieur]

First, my CT encircles the circuit conductors, the only imbalance possible is ground fault - so says Kirchoff

wrong
the pos seq current magnitudes/phases can be unbalanced
you lack the understanding to see that

 

[Ingenieur]

Well, the circuit imbalance is the method to detect a ground fault.

wrong
the currents must sum to 0 but need not be balanced
you are out of your league

 

[Ingenieur]

I'm working with an engineer from GE; they design and build this equipment, he knows what I'm looking for and has a CT in mind for me to use. The guy was a real pleasure to speak with.

A guy claiming to be an EE once told me that a center tapped transformer ( like those serving homes ) is 2 phase power. Is that your belief?

not claiming to be an EE
my alma mater and the state claim it

yes
180 deg out of phase

 

[buffalonymann]

wrong
the pos seq current magnitudes/phases can be unbalanced
you lack the understanding to see that

Only in your world, in the real world the only current imbalance results from current leaving the circuit. LOL

 

[Ingenieur]

here's a question

3 ph delta load, a, b, c
load between a and b, c open
i on and b, 0 on c
will a 0 seq produce an output?

 

[buffalonymann]

not claiming to be an EE
my alma mater and the state claim it

yes
180 deg out of phase

That's exactly what I thought you would say, and that is proof enough that you have very little understanding of electrical theory.

 

[Ingenieur]

Only in your world, in the real world the only current imbalance results from current leaving the circuit. LOL

not only in my world buckaroo

where does the i that 'leaves the circuit' go?

 

[Ingenieur]

That's exactly what I thought you would say, and that is proof enough that you have very little understanding of electrical theory.

so
are you saying if you scope L1-n and L2-n they will cancel?

 

[Ingenieur]

L1 v = 120/0 = 120 + 0j
L2 v = 120/180 = -120 + 0j

v total = L1 - L2 = 120 + 0j -(-120 + 0j) = 240

 

[Besoeker]

Could you explain how you arive at the idea it creates 2 supplies 180 degrees out of phase

Live to neutral voltages are opposite polarities. That's how the get 120V across each half and 240V end to end.

 

[Ingenieur]

Live to neutral voltages are opposite polarities. That's how the get 120V across each half and 240V end to end.

:happyyes:

elementary my Dear Watson

 

[Besoeker]

:happyyes:

elementary my Dear Watson

The kiss principle.

 

[drktmplr12]

Could you explain how you arive at the idea it creates 2 supplies 180 degrees out of phase

 

[Ingenieur]

1 picture = 1000 words (or a few equations lol)

even called 'phase'!!! :thumbsup:

 

[Besoeker]

Good. But that would be an unusual system for household power.