R1+R2 of a ring circuit

[Ste69]

I know you take the highest reading, though not sure if you take the highest reading on the ring circuit or a spur off the ring circuit?

cheers

 

[trev]

Whichever it is mate, obviously a spur will naturally have a higher reading

 

[NDG Elecs]

As Trev says record the highest. I would mention that the figure is for a spur and also jot down the average value of the RFCs r1r2 for the actual ring itself ie without the spur figures.

 

[GLENNSPARK]

come on boys...:

trainee section for this....

 

[Ste69]

excellent, cheers!

just to clarify

For when comparing r1+r2/4 to R1+R2, do i use the ring highest value or the spur highest value?

 

[GLENNSPARK]

excellent, cheers!

just to clarify

For when comparing r1+r2/4 to R1+R2, do i use the ring highest value or the spur highest value?

OK

the calculation of r1+r2/4 to give you (R1 R2) around the grounds so to speak does not take into account spurs....think about what r1, r2 & rn is.....:

end to ends...yes?

the value of (R1 R2) should be r1+r2/4.....we know that...yes?

the value off all points on the ring should be a Max. of 0.05 of each other....a spur will manefest itself by being considerably higher....thats how you will/should know its a spur.

its the highest value you would be putting down as the (R1 R2) of the circuit....this would be likely to be a spur...should there be any....

 

[GLENNSPARK]

but do not confuse a spur with what may just be dirty shutters.....

 

[Ste69]

OK

the calculation of r1+r2/4 to give you (R1 R2) around the grounds so to speak does not take into account spurs....think about what r1, r2 & rn is.....:

end to ends...yes?

the value of (R1 R2) should be r1+r2/4.....we know that...yes?

the value off all points on the ring should be a Max. of 0.05 of each other....a spur will manefest itself by being considerably higher....thats how you will/should know its a spur.

its the highest value you would be putting down as the (R1 R2) of the circuit....this would be likely to be a spur...should there be any....

Thanks a lot mate!

Sorry. one more question.

so if the reading of r1+r2/4 is not the same as R1+R2, is that ok because we are using the spur reading for R1+R2?

say on the ring you have r1 0.33 r2 0.56 rn 0.33............on the ring all readings are 0.25 but on the spur its 0.36....soooo the R1+R2 is 0.36. If you use r1+r2/4= 0.23. so it is off by 0.13 but with the 0.25 reading its ok.

are these readings good then?

really sorry, just want to get my head around this.

 

[GLENNSPARK]

Thanks a lot mate!

Sorry. one more question.

so if the reading of r1+r2/4 is not the same as R1+R2, is that ok because we are using the spur reading for R1+R2?

say on the ring you have r1 0.33 r2 0.56 rn 0.33............on the ring all readings are 0.25 but on the spur its 0.36....soooo the R1+R2 is 0.36. If you use r1+r2/4= 0.23. so it is off by 0.13 but with the 0.25 reading its ok.

are these readings good then?

really sorry, just want to get my head around this.

as long as all the points actually on the ring were stable..(to within 0.05 of ohm)..then yes...

let us not forget that your looking for a suitably low reading of (R1 R2)....as long as it concurs with the r1+r2/4 equasion

the whole point of (R1 R2)..is to prove theres CPC available at every point on the ring

so Ste69...:
can you tell us please how many stages there is to ring final testing (low ohms)

and if one of the outcomes is proving theres a CPC available at every point served....can you tell us another outcome?

answer here please:

 

[varilite]

Continuity of the line conductor proving correct polarity

 

[GLENNSPARK]

Continuity of the line conductor proving correct polarity

not quite....lol

we`re talkin about a 3 stage test here....arn`t we...

 

[varilite]

Ok end to end first check it's a ring

 

[GLENNSPARK]

Ok end to end first check it's a ring

yep...well done

and which 2 values on the end to ends would you be looking to develop into something you can use for the second stage test?

 

[topquark]

... and don't forget you can just as easily do the cross overs at a socket point you know is on the ring to avoid messing up the CU wiring. Easier to see which is the in and out legs too.

 

[varilite]

r1 and r2 /4 added to Ze to check if ZS complies

 

[GLENNSPARK]

r1 and r2 /4 added to Ze to check if ZS complies

no.

have another think about it...

 

[varilite]

r1 and rn

 

[GLENNSPARK]

r1 and rn

yep...

its R1 Rn around the ring...

what next?

 

[varilite]

Yes in the second part of test these values should be half of the values in the first part

 

[GLENNSPARK]

Yes in the second part of test these values should be half of the values in the first part

no...

its r1 + rn / 4= R1 Rn.....around the points....isn`t it..

why do you think we carry out an R1 Rn?