May I ask a question about the single vs two phase stuff

[jumper]

it was a joke
the equation is nonsense :lol:

I never said it was a 2 phase power system
only that the sec is comprised of 2 waveforms seperated by 180 deg, hence comprised of 2 phases

I know that, I get it. I saw the equation was a joke.

I did not mean to imply you didn’t get this stuff. I was referring to the second sentence.

My rant was not against you, but against the people who cannot see that and still realize thati by conventional naming, we call that Single Phase.

It is merely the way we series the two secondary coils to achieve the desired signals and amplitudes of two 120 voltages and one 240 voltage out of a tranny.

We get the voltages we seek by modeling and creating them by the way we build the tranny.

 

[SG-1]

Fine, but is not very often done that way. You would end up with DC in each of the three phases which is not good and not actually permitted in some places.

If I were going to actually use the DC I would configure the rectifiers for two pulses per phase, for a six pulse system. We use 3-Phase rectifiers to generate our DC control voltage at work. A 3-Phase variac supplies the ac into a diode bridge, at 100V there is about 6V of ripple. Just enough to dimly illuminate the LED indicator lights.

 

[SG-1]

Why do we call it single phase ?
We already had a system named 2-phase.
All of the individual loads are supplied by two CC conductors. Light bulbs, heating elements, motors, etc...

 

[LarryFine]

Why do we call it single phase ?
We already had a system named 2-phase.

Why are 2-position switched called 3-way?

 

[mbrooke]

Physics and NEC/IEEE naming conventions do not always match.

IMO, in this case they do match. :thumbsup:

 

[mivey]

Why are 2-position switched called 3-way?

You sir are trouble with a capital T.

 

[mbrooke]

You sir are trouble with a capital T.

In other parts of the world its called 2 way

 

[jumper]

IMO, in this case they do match. :thumbsup:

Depends how one looks at it.

Three different waveforms called single phase.....

 

[LarryFine]

You sir are trouble with a capital T.

Moi?

"Trouble with a capital "T"
And that rhymes with "P" and that stands for pool!" ~ from The Music Man

 

[SG-1]

Why are 2-position switched called 3-way?

It would have to be the number of wire terminals on the switch body.

 

[K8MHZ]

It would have to be the number of wire terminals on the switch body.

That is exactly why.

Hydraulic valves are named the same way. A 3 way valve has three ports.

 

[Ingenieur]

IMO, in this case they do match. :thumbsup:

:happysad:

 

[Besoeker]

Note the description:

 

[winnie]

Note the description:

View attachment 20899

Interesting.

Note both the caption at the bottom and the labels on the 6 secondary taps/coils.

What is the benefit of this arrangement over the more common approach of 6 diodes as 3 half bridges connected to a three phase wye?

-Jon

 

[Besoeker]

Interesting.

Note both the caption at the bottom and the labels on the 6 secondary taps/coils.

What is the benefit of this arrangement over the more common approach of 6 diodes as 3 half bridges connected to a three phase wye?

-Jon

If you mean a full wave bridge such as gets used as the input bridge on a VFD*, only one diodes conducts at a time so lower losses. But my point was the document call it six phase yet it is three centre tapped coils of the arrangement that is being referred to as single phase.

*If you mean some other arrangement, can you provide a diagram, please.

 

[buffalonymann]

Why do we call it single phase ?
We already had a system named 2-phase.
All of the individual loads are supplied by two CC conductors. Light bulbs, heating elements, motors, etc...

Because it is single phase and nothing more

 

[ggunn]

Because it is single phase and nothing more

Once more around the park, guv'nor?

 

[wwhitney]

Seems to me that the "two phase" camp is biased against negative numbers. If L1-N and L1-L2 are the same phase (multiple of 2), then if you believe in negative numbers, L1-N and L2-N are the same phase (multiple of -1).

Cheers, Wayne

 

[Besoeker]

Because it is single phase and nothing more

What we, UK, call single phase is one live and one neutral. What you are calling single phase is two lives and one neutral.

 

[Ingenieur]

Seems to me that the "two phase" camp is biased against negative numbers. If L1-N and L1-L2 are the same phase (multiple of 2), then if you believe in negative numbers, L1-N and L2-N are the same phase (multiple of -1).

Cheers, Wayne

1/180 = -1 + 0j
180 deg and a non positive qty are the same thing in this case

1/120 = -0.5 + (sqrt3)/2 j

what is the diference?
other than the phase angle