Thank you Stevenal. I'm sorry for asking, but did you mean that I need to set the primary side devices above the inrush curve meanwhile the devices on the secondary side (load) are not required to be above this inrush current in a TCC graph?
If so, do you know which standard (US) talk about this?
Hi everyone,
I’m setting up protection for a 13.8 kV to 400 V transformer and wondering how much inrush current should influence secondary-side protection. I know primary protection (relays, fuses) is typically set to tolerate inrush, but what about MCCBs or relays on the 400 V side?
At the...
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...
