I'm interested in learning how to perform motor starting studies. Can anyone give me any advice on any reference material I can use to learn this skill?
I can certainly empathize with you. I constantly worry about making mistakes and often lose sleep at night second guessing myself. Ninety-nine out of a hundred times, I worry for nothing. However, several times in my career I've discovered where I've made a decision in the past that I thought...
I apologize in advance for my ignorance on this topic....
If a neutral bus is solidly grounded, yet the neutral bushing connected to that bus (on the transformer) has a BIL rating of 150 kV, do you still have to worry about neutral-to-ground clearances between the neutral bus and grounded steel...
NEMA gives guidelines for clearances between live parts and ground and also live parts between phases for system BIL ratings and system voltages. (SG 6 - 1990 Table 32-1)
However, as far as I can tell, it does not give clearances between live parts of different system voltages. I'm mainly...
I recently purchased a radio fence for my dog and decided to mount the transmitter indoors. I had to run the antenna loop outdoors, so I decided to run the wires through the wall into an LB junction box on the outside wall. I then go down into the ground through conduit and just exit the...
Can anyone tell me where I can find a reference on modeling the surge impedance for transmission towers. I'm using this information to model a lightning strike on a transmission tower so that I may calculate propagation effects along adjacent spans.
jbartos:
I'm not interested in any particular level at the moment. I'm interested in knowing how to do this for all voltage levels from 120 V panels to 500 kV circuit breakers.
Thanks, rsherry. I hadn't considered the fact that symmetrical components requires balances phase components for each positive, negative, and zero sequence quantity.
I've recently applied for a license to use the free Alternative Transients Program. Does anyone have any idea how long it typically takes to get this license?
Stevenval:
I think you're right. If you look at the sequence network diagram for a L-G fault, you can see that the thevenin fault impedance is Z1+Z2+Z0 which is the same as 2*Z1+Z0 if Z1=Z2.
My questions were directed more to rsherry. I'd like to know what method she uses to calc offset...
If I'm interested in sizing equipment based on symmetrical and assymetrical fault data, then it seems to me that I need to know the assymetrical offset for each type of fault. I know that 3-phase faults are usually the highest magnitude, but not always. So, I think I probably need to know the...
I'm trying to calculate the assymetrical offset for a L-L-G fault and am not totally sure I'm understanding things correctly. If you look at the sequence diagram for a L-G fault and the Thevenin equivalent circuit for a 3-phase fault, it's easy to see how the X/R ratio is defined for each...
You wouldn't happen to have a contact number would you? I can't seem to get their webpage to work. It looks like there's an applet that supposed to load, but it's not working. And, there's no other info on their site.
Can anyone suggest a manufacturer of DC/AC inverters?
I'm looking for something in the 1 to 2 kVA range and has status contacts available for remote monitoring. These status contacts need to include transfer switch position as well as maintenance bypass switch position.
I'm looked at a lot...
Can anyone please point me to a guide on how to perform a motor starting study? I know it involves voltage drops in cables, starting curves, etc., but I don't know anything about the details.
Websites or books would be helpful.
What is the difference between a magnetic circuit breaker AIC and AIR rating. I see both listed, though I never see them listed together. Is it the same thing?
