Just A Couple Of Pics

[ricicle]

A Delta-Star transformer causes a phase shift of 30degrees iirc.

Correct in my experience although the primary was Delta wound and the secondary had two outputs (one Delta/one Star). The difference between these two outputs was 30 degrees thus giving six phases for the supply to a twelve pulse thyristor DC drive.

 

[Stoday]

A Delta-Star transformer causes a phase shift of 30degrees iirc.

Yes but the point was that the HV side was crossed. That causes a phase shift of 30° between the LV of this transformer and the LV of a transformer connected to the HV without a cross. It's impossible to phase out between the two LVs.

 

[Spark123]

To me, if you didn't have a transformer which resulted in a phase shift i.e. a star-star or a delta-delta all you'd end up with is a 180 degrees phase shift by playing about with the ends of the coils.

To get a 30 degrees shift you need to create a mixture of the other phases i.e. a delta-star transformer.

 

[Buzx1313]

so good to see red yellow blue again...

do miss thoses colours

 

[timtheenchanter]

I like these

edit: back soon, going to find somewhere to host my images....

sorted.

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• timtheenchanter
• 28 Feb 2011
• 1

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• timtheenchanter
• 28 Feb 2011
• 1

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• timtheenchanter
• 28 Feb 2011
• 1

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• timtheenchanter
• 28 Feb 2011
• 1

couple more pics here

//www.diynot.com/network/timtheenchanter/albums/8122

can anyone guess what/where they are??

 

[efiste2]

Transfomers used to be labelled RYBN or Hv side RYB, modern transfomers are marked abcN or A B C for the HV side....But going against the RED-RIGHT-RULE of thumb.....Looking at the HV box RED or L1 of A is on the LEFT!!! The CT's also have to follow the Phasing.....

Switches in new language are L1,L2 and L3

 

[Stoday]

In the old days you would never have seen singles going through a steel case like that. You'd have a paxolin panel or a slot between phases.

 

[aptsys]

Doesn't the grounded semi-conductive screen negate the need for paxolin cable entries?

 

[bernardgreen]

In the old days you would never have seen singles going through a steel case like that. You'd have a paxolin panel or a slot between phases.

Wasn't that necessary to reduce eddy currents in the steel due to the magnetic fields from the currents in the phases. So what has changed ?

 

[westie101]

what has changed

Primarily the construction of the cable with a fully earthed copper armour(!), under that a semi conductive layer, XLPE insulation and solid aluminium cores.

As most switchgear is for outdoor use also we cannot use anything but steel over all parts of the gear so paxolin etc. would be non-compliant