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Hi cranky108, I apologize for any confusion earlier. When I mentioned "PLC," I was referring to a Programmable Logic Controller. For instance, certain Kohler generators use an AMP403 Controller, which provides genset protection. My understanding is that this controller sends a signal to the main...

I’m modeling a system with an Eaton IZMX-16 (1600A) circuit breaker equipped with a PXR25 trip unit, and I need to configure the overcurrent protection to 350A. However, the lowest setting I can achieve is 640A, based on the PXR25 trip unit’s minimum multiplier (Ir x 0.4). Is there a...

I'm conducting an arc flash study and encountered an issue when testing a bus failure at 0.4kV (MC-002). The protective device immediately upstream of the bus does not open; instead, the device farther upstream does. In the attached case, and according to the TCC, I would expect the breaker that...

The upstream transformer that energizes this system is solidly grounded. Please can you clarify more why it would not make sense to detect low intensity ground faults? Thanks!

Thank you dpc!. That's what I'm trying to achieve but by design, the minimum delay time that I can set on the C441 is 1 second. At first I thought that ETAP had it wrong but the catalogue and user manual also says that the time delay setting goes from 1 second to 60 seconds.

Hello! I'm trying to coordinate ground fault protections for several low voltage motors (2, 5 and 11 kW) that are protected by a C441 Motor Insight (Eaton). About the pickup current, I'm considering 3% of Full Load Current of the motor but for the instantaneous region I'm having trouble as the...

I work in the mining industry and we use a table that has load, operating and demand factors for every type of load (conveyors, fans, crushers, compressors, blowers, hoists, etc). However, I want to validate these values with a book or any reference.

This is a 230/400 V diesel generator (QAS 100 - 100 kVA). Which standard specify a ground grid resistance value of reference for this kind of installation (isolated)? I was reading IEEE 142 and 4.1.3 "Recommended acceptable values" specify: "Resistances in the 1 ohm and 5 ohm range are...

We have containers with offices inside and the lightning protection mast is supported to a container with galvanized pieces. Also it has three steel wind wires attached to the top of these containers. All of this containers are grounded. Could it be a problem with this configuration? Edit: It's...

I've been told that a single lightning protection (franklin type) mast covers around 250 meters (800 ft). The total area under study is between 200 and 300 m2. Under which standard are these masts covered? Thanks!

I only have 2 years of experience doing engineering and now I am in the construction area as an electrical supervisor. The project is really simple, just 2 pole transformers (100 kVA each) and an optical fibre tie-in, of course with a few electrical and instrumentation panels. The thing is that...

I'm trying to model these systems in ETAP but I don't know how to. These systems consist in a rectifier to energize DC overhead lines that will feed the truck's wheels through an inverter and a induction machine. I was thinking in a lumped load with a 65%/35% ratio (motor/static load). Any...

I'm a trainee engineer and I want to learn good practices when drawing a oneline diagram for a project in my work. Do you know an online resource where I can study these diagrams that are ready to construct with? Thanks!

Is around there an open source software, excel sheet, etc to plot at least the standard curves that protection devices often utilize? I use ETAP but sometimes is time consuming to just check a TCC for an specific relay. Also I wanted to ask if it's the same to use an Extremely Inverse curve for...

I was designing a oneline diagram at work where I have substations (5) with a distance of 1 km between the first one and the next one (and so on). At tie-in I have a switchgear with the corresponding main circuit breaker, however, I have a cutout fuse upstream (2 km) of the switchgear to protect...

I'm currently working on oneline diagrams and I need to determine the current rating for the horizontal bus in motor control centers, switchgears, switchboards, etc. Which reference should I consider in order to write a voltage/current/short-circuit rating which is commercially available? For...

Thanks prc, that is what I wanted to hear because I couldn't find an IEC standard that contemplates damage curves.

I've always seen a 50/5 for almost any load but recently I wanted to understand why my coworkers select that ratio. On what depends? FLA, direct starting (7 times FLA), etc... For example if a 575V motor has 190 FLA, a 50/5 would be undersized right? Any help would be great, thanks!

I'm trying to figure why ETAP gives a transformer damage curve with a huge difference under ANSI Std and IEC Std. If you have another source it would be great. Thanks!

I'm trying to assign a TCC curve for a Noja recloser in ETAP (Extremely Inverse, Very Inverse, etc). On what depends these curves? How can I be sure that I'm selecting the correct curve? Also, if you know of a reference to educate myself I'd really appreciate it. The system I'm trying to model...