R1+R2 Tests on 3Phase

[E.M.F. MAN]

Hi again sorry to be a pain but this 2391 practical is twisting my brain. Do you have to do a R1+R2 test on a 3 phase motor circuit and if so what is the proceedure???

 

[m4tty]

Not sure but wouldnt you test between L1 & CPC, L2 & CPC, L3 & CPC and note the highest as R1 + R2.

Might be wrong tho so await being corrected.

 

[E.M.F. MAN]

Hi again, This is the thing that is confusing, can it be done the same as the insulation resistance test by joining L1+L2+L3 together and to earth???

 

[Zeespark]

Nope 2 conductors together.

AndyGuinness

 

[sparkytim]

You can test all 3 Phases seperately to CPC and readings should be much the same. if you connect more then 1 phase then it will reduce the true reading as you have resistence in parrallel

As this test is to confirm continuity of the CPC then one test would suffice, but I tend to do it to all 3 just as matter of interest and this checks all 3 Phase conductors are equally well terminated.

 

[E.M.F. MAN]

Thanks all for your input...

 

[Brian 157]

As a 2391 assessor I expect all 3 R1+R2 readings to be taken, as for recording the results either record all 3 values (if recording the circuit on three lines) or the highest (on one line, but indicate that it is a TP&N circuit).

 

[Andy™]

As a 2391 assessor I expect all 3 R1+R2 readings to be taken, as for recording the results either record all 3 values (if recording the circuit on three lines) or the highest (on one line, but indicate that it is a TP&N circuit).

dont see the point in R1R2 on each phase - after all, your only requirement is R2. R1R2 is normally done to use R1 as your wonder lead

 

[Brian 157]

[quote name='Andy