3 phase testing???

[mickytuff]

Hi all, done a lot of single phase testing but not much on 3 phase.any advice on this part of testing like loop readings when testing ie between phases and psc values, any advice greatly appreciated folks:smilewinkgrin:

 

[needasparks]

Good question mickytuff, this part of the site i think is great for learning. I hope you get some usefull tips on this. I'm gonna let someone else start the bun fight but for now just get to know all the functions on your meter as it will make the answers you get easier to understand.

 

[mickytuff]

thanks for that, i hope i get another reply soon.......

 

[Edd]

For PSCC test between Phase and neutral, then double it. And for the Ze do Each phase to Earth and take the highest reading..

 

[johnboy6083]

they teach you to double your phase to earth/neutral, but its actually closer to x 1.732.
if your tester requires a neutral for Zs, and you have a balanced 3 wire load, then you can put your neutral lead on the CPC.

 

[SirKit Breaker]

they teach you to double your phase to earth/neutral, but its actually closer to x 1.732.
if your tester requires a neutral for Zs, and you have a balanced 3 wire load, then you can put your neutral lead on the CPC.

We are taught to double it because it is easier for the maths and memory, and err's on the side of caution. It also an acceptable answer if the question crops up on the 2391 course. There are Instruments about which can do phase to phase, but unless you know for certain then assume it wont and do the calculation, cos if you do and it isnt, you wont like it, and neither will the instrument.

Cheers........Howard

 

[johnboy6083]

other things relevant to 3ph testing, is on R1 + R2, and Zs, it is the highest of the three phases that is recorded. As part of the functional tests, phase rotation must be tested.
During inspections, one of the extra items that must be checked, such as that all phases and neutral pass thorugh the same hole in ferrous containment, unless a slot is cut between seperate holes.
balncing of loads is also another consideration, although in practice its almost impossible to do perfectly.

 

[MarkieSparkie]

... phase rotation must be tested. ...

It's phase sequence that you should test NOT phase rotation which something quite different. 612.12