Thanks Ralph
Just what I did and found it to work. Initially the trip time was a little long for my liking. I then found that if I move the horseshoe magnet located under the disc a little further away from the disc that the trip times shorten. Closer to the disc, the longer the trip time.
So...
Can the disc of a 5amp TJM10 relay be used in the same o/c element of a 1amp TJM10 relay? I have a broken puter frame-piece and it involves less work and adjustment to swop the frame with the disc than to dismantle all. I can understand that the current coils will differ, but are the discs the...
Sverker 750 is a nice unit but very sensitive to supply fluctuations. Not advisable to run it from a portable generator for remote location testing without some form of voltage stabilising on the supply to the unit.
Any links to info on the Pro test software?
Making the smoke come out is...
For earth fault testing, inject across 2 phases and short them out on the P2 side of the CT's (ie 1 lead of test unit to P1 of say red, the other to P1 of say white, then connect the P2's of red and white together with a suitably sized lead). Avoid using flexible aluminium conductors/leads for...
Thanks Ralph. I will work my way through it all.
I am still open to hear what others have to say as well.
Making the smoke come out is easy; getting it back in is a bugger.
Doing a recent installation of a 2,5MVA 6,6kV/525V delta/wye trafo in a sub, the question came up again. Earth is earth, or am I wrong? There is an NER installed on the LV side. Should the earth conductor running with the MV supply cable be connected to the same common-earth bar in the sub as...
In the mist belt of the west African Coast we have changed to "Rodurflex" silicon rubber insulators on 33kV network and witnessed a remarkable improvement. Heavy sand and dust storms followed by heavy sea mists and no more flashovers. They are well worth the money. Interesting find...
1) How do I determine the minimum distance between 2 parallel cable runs of different voltage, eg. 11kV and 380V?
2) How does the one voltage effect the other, and why?
Bigamp
Oops! That is supposed to be (AC).
The stations (5"X3") used are made of a non conductive material, but have an earth connected to the earth connection point inside the enclosure. Could the operator be completing a circuit for the leakage current from the station through the...
In the designing of an extension to our plant, the issue of operators experiencing electrical shock from operating the push buttons on numerous existing IP65 rated field stop/start stations has raised a few possibly thought provoking questions. The debate is about which control voltage to use...
If the 2 trf's are to operate simultaneously, the difference of impedances should be less than 10% of the lower trf's imp. value.
Example:
trf1 = 8.35; trf2 = 7.67
8.35- 7.67 = 0.68
0.68 / 7.67 *100 = 8.87%
<10% difference, thus can do.
We use Snapshot, works fine. Enough detail to locate the hotspot on 66, 30, 6.6kV and 525V systems, from as far as 8m.
As a first time buyer, I would also try a few cameras (if renting is an option) to find what suits your needs and budget.
DanDel
-They are paralleled primary and secondary (buscouplers on pri and sec).
-Secondary voltage drops enough for motor drive contactors to "drop out" at plants 7km and 32km away.
-My mistake, further enquiry reveals that the other trf does the same when re-energised.
-Source: 66kV...
Kantor, do you do infra red monitoring/imaging on your system as part of a condition monitoring program?
Loose connections can be spotted and repairs effected before they become a problem by comparing the temperatures of adjacent connections in the same box. We have an extensive infra red...
