Here Goes Nothing...

[basic]

Ok, can any1 explain to me this

In a 3phase and Nuetral system operating on a line voltage of 450V the phase to nuetral voltage would be 260V.

I just don't understand. I mean I really don't understand.

If any one can just give me a quick explanation it would be really cool.

Thank You

 

[andy]

there are 3 lives. between each live there is 400V. in the middle, there is neutral, which is 230V between this and any phase. its not 230/460 because the phases are 120 degress from each other. that any help?

 

[andy]

phase to nuetral voltage to be 260V

no. in the UK its 400V phase-phase, 230V phase-neutral

 

[Lectrician]

Although, the 450/260v has the sq/3 relationship Where did you get these figures from??

 

[basic]

That was the question in a mock and the answer was 260v!

I could'nt understand it either. My group are split and to be honest the stand in lecturuer was'nt to confident either.

Can any1 be a hero?

 

[andy]

That was the question in a mock and the answer was 260v!

I could'nt understand it either. My group are split and to be honest the stand in lecturuer was'nt to confident either.

Can any1 be a hero?

the old voltages in thr UK were 440V phase=phase and 240V phase-neutral. dunno where the 260V came from

 

[plugwash]

the old voltages in thr UK were 440V phase=phase and 240V phase-neutral.

that pair of voltages CANNOT go together. The old standard in the uk was 415V phase-phase and 240V phase-neutral. I'm pretty sure 440V systems existed but not for normal domestic/commercial power supplies.

the phase-phase voltage is always

times the phase-neutral voltage

so if the phase-phase voltage was 450V the phase-neutral voltage the phase-neutral voltage would be 259.80762113533159402911695122588V which is near as dammit 260V

 

[basic]

450v /3 = 150v
150 x 1.73 = 259.5v

being that 1.73 is the square root of 3

Is that what you were saying???

 

[andy]

the old voltages in thr UK were 440V phase=phase and 240V phase-neutral.

that pair of voltages CANNOT go together. The old standard in the uk was 415V phase-phase and 240V phase-neutral. I'm pretty sure 440V systems existed but not for normal domestic/commercial power supplies.

the phase-phase voltage is always

times the phase-neutral voltage

so if the phase-phase voltage was 450V the phase-neutral voltage the phase-neutral voltage would be 259.80762113533159402911695122588V which is near as dammit 260V

i thought it used to be 440v? i havent done much with 3 phase

 

[supersparks]

i think 440v was when "split phase" was used?

or maybe that was 460v split phase

 

[Lectrician]

t was 480v split phase, and is now 460v split phase

 

[andy]

t was 480v split phase, and is now 460v split phase

er... what is split phase?

 

[supersparks]

A standard UK three-phase supply will typically consist of a star connected three-phase arrangement, with 120 degrees between phases, with neutral connected to the star point.

This commonly gives 400V between phases and 230V between phase and neutral.

By contrast, a typical split phase arrangement has only two phases available, 180 degrees apart.(usualy in rural areas where the rec don't think its worth their money to supply the three phase over head lines usualy at the 11kv stage)

This gives 480V between phases and 240V between phase and neutral.

but its now 460 between phases...thanks lec

 

[Lectrician]

Basically, the two phases from the delta fed 11kV may be used to transform down to 230volt single phase.

Sometimes the transformer used has a bigger secondary winding providing 460v, this winding has a centre tapping which is the neutral. This is earthed down aswell.

as said above, 460v between the two phases, and 230 volt from either phase to earth.

If this confuses, think of the yellow site transformers with their 110v and centre tapped earth.

 

[andy]

Basically, the two phases from the delta fed 11kV may be used to transform down to 230volt single phase.

Sometimes the transformer used has a bigger secondary winding providing 460v, this winding has a centre tapping which is the neutral. This is earthed down aswell.

as said above, 460v between the two phases, and 230 volt from either phase to earth.

If this confuses, think of the yellow site transformers with their 110v and centre tapped earth.

i understand now. but why use split phase?