2391 - would like to double check advice from tutor

[chronyx]

Would appreicate any clarification of what I have been told at college.

The tutor has told us to use 240V for calculations as this the output of a sub-station. Do you agree, or should I use standard 230V?

We were also told to remove the bonding conductor from the pipe clamp to test the continuity without parallel paths, but surely the logical thing is to disconnect at the board so that you also test the connection from the clamp to the pipe?

For those who remember the test board, am I right in assuming the MIMS cable sheathing earth is verified by the standard R1/R2?

How did you test the motor starter R1+R2 and insulation resistance values? Press in the contactor, or split the supply and load and test individually?

Cheers chaps :cheesy:

 

[rich.250]

I would use 230, and did on my 2391

Disconnect bonding at the db

Yes r1+r2 is verified in the same way on mi

And I would be tempted to link out the contactor to be able to test r1+r2 at the motor

Hope this helps

 

[chronyx]

Certainly does Rich, thank you very much and enjoy what's left of the weekend.

 

[rich.250]

No worries mate.

 

[brman]

it has been suggested to me that for the motor we measure method 1 to the contactor and use method 2 to measure R1 and R2 for the contactor to motor then add them all together.

I guess it all comes down to which is going to be quicker as they are all valid approaches. I suspect his checklist expects him to see method 1 on at least one circuit but after that I reckon it is your choice as long as it gets the right results.

And yes, 230V has been drummed into us, as has removing the bonding at the MET and measuring to the pipe, not the clamp.

 

[chronyx]

Thank you, this is a great help to my classmates too! The tutor is a nice bloke but not a natural teacher.

 

[i=p/u]

how you going to check you 3phase stuff, is it L1 to earth nd check at points on circuit then the same for L2 asnd L3

 

[brman]

I believe so. Basically treat it as 3 different circuits. Until you come to the IR test where you need to test all combinations of course.

 

[rich.250]

Yes as brman says.
If you think of the schedule of tests for 3phase. It will be three lines, so 3 r1r2s.

 

[SirKit Breaker]

If you get any questions that need voltage, other than one where you need to work it out, you will be given the voltage value.

i.e. You wont get a question starting like:- On a single phase supply. It will be worded, On a single phase supply with a nominal voltage of 230v, or words to that effect.

You may need to do volt drop calcs, but even then you will be told the voltage. The 2391 exam does not leave things open to interpretation.

Cheers.............Howard

 

[SirKit Breaker]

Would appreicate any clarification of what I have been told at college.

The tutor has told us to use 240V for calculations as this the output of a sub-station. Do you agree, or should I use standard 230V?

We were also told to remove the bonding conductor from the pipe clamp to test the continuity without parallel paths, but surely the logical thing is to disconnect at the board so that you also test the connection from the clamp to the pipe?

For those who remember the test board, am I right in assuming the MIMS cable sheathing earth is verified by the standard R1/R2?

How did you test the motor starter R1+R2 and insulation resistance values? Press in the contactor, or split the supply and load and test individually?

Cheers chaps :cheesy:

You are worrying too much. You will be walked through the tests as part of the course, before you do the practical assessment. It doesnt matter how you do the tests, as long as you do them all, do them properly, and work safely.

Cheers............Howard

 

[chronyx]

You are worrying too much. You will be walked through the tests as part of the course, before you do the practical assessment. It doesnt matter how you do the tests, as long as you do them all, do them properly, and work safely.

Cheers............Howard

I've done the course, and it was of limited use. Like I said, we were told how to do the bonding test incorrectly.

 

[chronyx]

My exam is today, so having a revision session!

Would anyone be able to confirm what details can be obtained only by enquiry (From the DNO) rather than measurement?

I am thinking earthing arrangement and in some cases the supplier protective device.

Number of phases?

Ze, frequency, phase sequence, Ipf and voltage can all be measured.

 

[timbobelfast]

DNO enquiry will be Ze and Type and size of main over current protective device.

Got my exam tonight aswell so best of luck to everybody else taking it.

 

[brucelee]

good luck to you both