Ze of 3rd , 4th db etc

[Jay Sparks]

Hi Guys

I know that if you have a main DB feeding a 2nd DB, then the Ze for the 2nd DB is:
Zdb = Ze from origin + (r1 +r2) of the cable supplying the 2nd DB. Or measured Zs at the second boards supply. But how do you then get Ze for, say a 3rd DB fed from the 2nd and then Ze for a 4th DB fed from the 3rd etc?

Any advice would be appriciated

 

[JUD]

2nd DB - Zdb = Ze (Origin) + (R1 + R2) of cable supplying 2nd DB

3rd DB - Zdb = Ze (Origin) + (R1 + R2) of cable supplying 2nd DB + (R1 + R2) of cable supplying 3rd DB

4th DB - Zdb = Ze (Origin) + (R1 + R2) of cable supplying 2nd DB + (R1 + R2) of cable supplying 3rd DB + (R1 + R2) of cable supplying 4th DB

.....and so on

 

[robsparky1975]

Although on a periodic report etc it would be ZS not ZE(taken at origin)

 

[Jay Sparks]

Cheers Guys,

So basically after the first board your Ze at the others is actually the Zs reading of the cable supplying that particular board. Nice one.

 

[robsparky1975]

Yep on a periodic report,you will find ZS reading and pfc for that db,so zs at that point would be the sum of ze at origin plus R1 & R2 of the sub main circuit to next db and so on,but ze is only taken at origin.