3 phase supply voltage

[reynard116]

Has anyone ever encountered this before?

p1 to earth 240v
p2 to earth 110 v
p3 to earth 400v

on an incoming TNS supply. Then 5 minutes later back to normal. 240v to earth on each phase.

 

[stef]

I have. Was mainly down to a missing phase. In your case might be a termination fault.

 

[GStueyXR]

Was there work going on at transformer?

 

[reynard116]

All terminations apear to be ok. No work at the transformer as this is on site and in the next room to where these measurments were taken.

I will monitor this through out the day. I may even put the energy power monitor onto the supply and check the graph over 24 hrs.

We have had quite a few problems over the years with drives on this supply and now obtaining strange readings from the 240/110 step down transformer in this panel. This is what got me to check the incomer.

Could this be a bad earth? The soil is very wet and sandy where the star point is grounded.