I am involved in some research about subject. Quite frankly I was a little concerned as to the size of these guys relative to a severe ground fault, e.g. 65kA. I just received a letter fromthe Dept. of the Navy with reference to the effect. I'm told that they are pulling them off their ships...
I was wondering if anyone has had experience with application and ROI with these guys. The input I've received thus far is how did we ever get along without them! My application is shipboard.
Thanks
where did I goe wrong? I braced the bus bar on about 2 feet intervals meaning supported to frame front and back. I was referring to the distance between insulators. Most of our applications are low voltage, 480 down. The question is: Is there a table (other than the one I have) that will give...
Can anyone help me with bus bar spacing for different kA bracing? I have a spread sheet with formulas but it seems way over kill. I thought that 21" between insulators was capable to withstand 65 kA but me table says it should 7" for single 1/4" x 4" bus!
Thanks,
I noticed you guys give a lot of thought for worst case scenarios. I agree with that but I would think along the lines (motor starting and sizing generators) with the technology that I see daily, i.e., permanent magnet generators. We have a lot of customers that are not aware of the motor...
I work as an EE for a switchgear company and assure you that UL891 is more stringent. Ironically though, their not interested in short circuit and coordination studies. I you claim 10 kA, you build to 10 kA. The big difference is bus bar sizing, bracing and name tags.We build most of our...
I appreciate you folks response to my questions. I didn't get the answer so I must have ask it wrong. Here goes again:
Bus bar tables reflect imessity factors and degree rises in centigrade. Wonderful! Now I have to size bus bar (been doing it for years via IEEE table A27 but when evaluating...
I am confused as to why bus bar ampacity tables show a higher ampacity of bus sizes with a higher degree of temperaturs, i.e. 50 deg. C apposed to say 75 deg. C.
anybody know?
Thanks
I agree with one of your respondants, increase your power factor! With such a low power factor, heating goes to the moon consequently raising the exciter current. Common on drilling rigs. Put a recording DC ammeter on your field leads and watch the trend.
Jim