Nice photos and I see Unitrol modules, small ones. I have seen these around on other plant. The biggest one I worked with was feeding a 500MVA generator so that was a set of six panels fed by a 3.8 MVA excitation transformer. That system was quite complex while my old school 1.5 MVA unit is...
Hi Catserveng. The problem is not being unfamiliar with generator and diesel gensets, the problem is I have not worked with anything this old. First time seeing a magnetic amplifier, never saw one before this job, assuming that is what it is.
I have people telling me that there's an amplidyne...
Hi TugBoatEng. Accessory drives, not sure; are these going to be accessible on the side of engine? Not sure that there is anything at the far end of the engine, don't have a good photo of that.
A replacement AVR may be an option, but only with a PMG installed as well, which is what you are...
attached image of my AVR which I am assuming is a magnetic amplifier. No data, drawings next to useless, no useful nameplate on this unit. I see winding sticking out the ends and this makes me think, magnetic amplifier. Looks like a toroid style than reactor units, but these were around, I...
Hi crshears. Firstly, this is a problem which someone handed over to me after the original engineer died. The second engineer was unable to devote enough time to it. Now I am the third one looking at this wonderful old school genset
Regarding Magamp, trouble is, how do I know that I am looking...
Hi Hoxton, yes I know it is old but my client wants to use it, if possible. It was working until the changes were made in the past year, and it should work again at least until the day it finally dies.
External changes : replaced original 11 kV switchgear with new 11 kV switchgear, which means...
I have an old diesel generator which has had external modifications and now has issues running; it starts but runs badly. I am trying to narrow down what is installed and as there is very little information available, I am struggling with this. The alternator is 1.5 MVA, operates at 11 kV, is...
More terminology that needs to be defined. A FEEDER will hook up another electrical panel? A BRANCH means connected to loads like lighting and power sockets, and motors if it originates at an MCC?
I understand feeder and use this the same way. A circuit that supplies a downstream electrical...
Thanks for that link to the Eaton tutorial. It makes panelboards and switchgear a little easier to understand. Still classifications that are generally confusing to me, particularly what the difference is for a switchboard, but then switchboard is not used in IEEE-1584, so maybe it doesn't...
Hello everyone,
Might seem like a too basic question, but comes down to being new to doing arc-flash calculations. I am looking at IEEE 1584 and where it states that there are classes known as LV switchgear, LV MCCs and panelboards. Just concentrating on low voltage with this. This standard is...
Hi,
Can anyone share a copy of this old standard? I have switchboards built in Australia to this standard, but I don't have a copy of the standard so I can't see what it required. It looks like I could buy it, but it seems like a waste of money since it is otherwise a long superseded standard...
Your Unigear switchboard has an IAC rating (internal arc containment) to match the IEC standard requirements. This means that flash-overs inside the switchboard in the cable compartment or the CB compartment are safely vented. I can see this in the system you have, ducting installed overhead...
Hoxton, can you provide the names of places where failures have occurred? I can then search what is available on the web.
GJY, thanks for that suggestion. We have thick insulation everywhere so its a bit of a guess what the external temperature would be if the internal temperature was reaching...
The cell fronts would definitely feel warm after some running hours. I can't see any extra heat effects on the fixed contact, centre leg, or the moving contact. The impression of extra heat is on the bolted connection area of the centre white phase.
Waross, these flexible leads are factory...
Thanks for your thoughts. Do you guys have these motor control centres with cooling fans installed? We don't normally. An exception is for a section carrying a variable speed drive, but a plain old CB/contactor/overload cell (or electronic motor relay as this one has) never has cooling...
A couple of months later, I have gotten hold of the contactor from the photos at the top. It is now easier to see the centre pole at the end that was getting the most damage. The electrician that was repairing this thought that an arc was escaping from the contactor and hitting the cable...
Bill, this lead with the verdigris on it is in a removable cell, installed in a motor control centre, and within a stand-alone building. Air issues could be from the sea as the wind can blow sea air our way, and/or cooling tower chemicals which we have seen affecting other parts of the plant...
Cupric Oxide (CuO), a stable black solid formed by heating copper in air at 300 - 800 celcius. That's really good to know. Always something new to learn. I will see if I can find evidence of black on the connection side.
Other joints that have the same lead, and have given trouble, have some...
Thanks for comments. The black carbon I see is produced from the PVC boot degrading?
The leads are manufactured by Cubic as busbars made from braided copper and the ends are factory forged into solid pieces. We have a number of these used in starter cells. Most are OK but some have given issues...
Looking at the attached photos, what's your first thought about what has failed? This cell set off an aspirated smoke detection early alarm. Heat damage (bad connection) or arcing damage (escaping from contactor) or something else?
