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 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.
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?
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...
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?
Can anyone recommend a DC current transducer that can measure up to 100 Amps (1% accuracy) and operates off of 125 VDC or 24 VDC? (125 VDC is preferable) The required output is 4-20 mA.
I'm looking for something that is fairly sturdy and can be mounted to a backplane in a small NEMA Type 12...
I'm not exactly an expert on the NEC, but I'm trying to learn. I'm currently working on a project that involves power supply cables (208/120 V - 2000 Amps) being routed through duct banks. The cables are going to have to be derated, due to the fact that they are surrounded by adjacent duct...
We're installing test equipment inside the high bay of a manufacturing facility that will utilize voltages up to 400 kV (Line to Ground). Can anyone tell me what codes or standards would be relevant to the installation of a high voltage electrical test facility contained within a building?
I'm studying for the PE exam and am trying to refresh myself with transistor circuits. Everything has been making sense up to this point. Then I ran across the problem given below.
Can someone please tell me if there is an error in the problem or solution. It seems to me that a 5.4 volts...
Can anyone tell me which IEEE Standard gives guidelines on overcurrent relaying? I'm thinking it is C37.90-1989 (R1994), but I'm not sure.
I'm looking for the standard minimum coordination time buffer between time/current curves. I"m thinking it is 0.3 seconds, but I'm not sure.
Is there a generally accepted relationship between a transformer's positive-sequence impedance and it's zero-sequence impedance? I believe that manufacturer's usually only test positive sequence impedance. I'm not aware of any conversion, but there must be some relationship.
Any suggestions?
If two panel boards are located across an isle from each other, what is the total distance required between the face of the two panels? (<600 V, No live parts on either side of panel) If I'm interpretting NEC 110.26(A)(1)correctly, I think it should be 3 ft. for each panel (6 ft. total). Or...
If you have a differential relay (GE Multilin 745) that has time/overcurrent elements, then why do you need the instantaneous differential element? Wouldn't the overcurrent instantaneous element perform the same function?
