I'm using ETAP underground design latest version. If I have two duck banks, one has a layer of fluidized thermal backfill, and the other doesn't, why are they coming out at the same temperatures? See attached.
in this example, Concrete RHO=30
FTP RHO = 40
Earth RHO = 200
I'm using ETAP underground design latest version. If I have two duck banks, one has a layer of fluidized thermal backfill, and the other doesn't, why are they coming out at the same temperatures? See attached.
in this example, Concrete RHO=30
FTP RHO = 40
Earth RHO = 200
ScottyUK the UPS option was remove because of cost. A 480V 3/P UPS that is large enough to start the motors is about 26K. had about 3 manufactures price this for me
mikekilroy: great point! I am looking at a price point of between 1k-and 2k each for the first 500 units.
Skogsgurra...
there is not enough inertia to get the CFM I need.(@14 seconds i only have about 25% of the CFM i need) that was my first and most obvious path. next i tried to see if i could increase the rotating mass of the fans... for various reason this did not work. then i thought i could add more fans...
Battery's in series is not an issue for me. VD is not an issue. just need to find a VFD that will do this with no power on primary AC Bus. perhaps i'm posting the the wrong place. really need a VFD expert.
I have a 480V 3 phase fan motor (<5HP) that i want to keep running for 14 seconds once the power it cut off. is it possible to connect a string of batteries to the DC bus of the VFD that will keep the DC bus energized in the event of a power outage? the DC bus would also have to keep the...
One of the biggest misunderstanding about RHO is that engineers get the soil tested and then say " look it is X Rho In-situ lets use X RHO" good paper here on this. http://www.neher-mcgrath.com/41/neher-mcgrath_FAQ.html
Reality is present RHO is no guarantee of future RHO, The real truth is...
55 is not a safe number to use any more than 90 is a safe number for earth. We have concrete tested and it the RHO can range from 45-90.
Reality means you live until you die. The real truth is nobody wants reality.
great info thanks all. but my main area of concern is copper and aluminum bus bars that are inside electrical switchgear.
again thanks
Reality means you live until you die. The real truth is nobody wants reality.
Hello I am looking for information on the off-gassing or out-gassing (I have seen both terms used) of Electrical PVC conduit at various temperatures. Is this information available??
Reality means you live until you die. The real truth is nobody wants reality.
First of all I am not a chemical engineer so some of the terms I use may be incorrect but I will try to get my point across.
I have an HCL gas issue and I am looking for a table that will show at what PPM level corrosion will start of various materials.
The main materials in question are Steel...
Talking to SQD now. but they want me to replace the breaker on my dine. This was a brand new breaker. that saw a 40KA fault.
My point for posting was to find out more info on just what the "expectations" are for the end user. I think that i have convinced myself that this is a SQD issue and not...
still not convinced.
according to the lit. new masterpact breakers are designed to meet IEC 947-2
this is taken from page 10 of the attached document
______________________________________________________
IEC 947-2 & BS EN 60947-2
This standard replaces IEC 157-1,
applicable since 1973.
The...
Sounds like a bunch of CYA to me. If I really have to take the breaker out of service and test it after any fault trip I might as well use fuses.
thanks to all that responded.
Ohm's it not just a good idea, Its the law.
"the UL standards require only a very limited number of successful operations at the maximum fault current - I believe the number is six, but I'm not sure and I'm too lazy to look it up.
"
what is the UL standard for this. the breaker in question is a SQD master pack NWH
Ohm's it not just a...
