I have been asked to make some generator curves, a Decrement Curve and a Thermal Damage Curve using EasyPower software. The generator data sheets were provided and I have attached them here.
I have found most of the information but am stuck on where to find:
> Field Forcing current as a per...
On an installation at a condominium complex the transformer is a 300kVA, 208/120V secondary. The secondary conductors are 500mcm AL 6 per phase. Transformer FLA is 832A so cable capacity is 1860A more than double transformer FLA. Each conductor has a BUSS Cable Limiter CDB-RV. I could not...
This cut-out is feeding a riser cable going to a pad mount transformer. Since the cut-out fuse blew and the cut out fuse holder fell open as it is designed to do, this would obviously indicate a fault. Therefore, I am surprised that the utility lineman just re-fused the cutout and closed it...
I think I may have mis-stated my question. I was looking feedback on people's experience with particular guards. For example: tried xyz's guard on pole mounted transformers and they blew off on wind speeds greater than 40mph. Or ABC brand looked great but the linemen hated installing them...
Hello,
I am working with a utility that is doing a 2400V delta to 4160V grounded wye conversion. One item that we are looking at is wildlife protection, mainly from birds. This is an island and there are no squirrels. It is an island so there is salt water so that may be consideration in...
Unless the barrier is a tested configuration, I don't believe you can take credit for it isolating an arcing fault. Unless it is specifically arc rated and testing equipment, I assume the arc will jump to the line side of the breaker and the upstream remote protective device will clear the...
You may want to post this question in Jim Phillips' brainfiller arcflash forum as there are people there who have been on the standards committees and should be able to answer.
What was going on at the time? Was a breaker being racked in? Was it being closed? Was it being opened? Was there a fault on the circuit it feeds and it was tripping? What is the maintenance history of the breaker? What kind of trip units are on the breaker? Was it isolated to one breaker...
The SCCR rating of the panel is 5kA as that is what is on the panel. That is what you have to live with.
Just because people confuse terms such as available fault current, Have you modeled the system using the available fault current obtained from the utility? This would not be on a chart...
start with reviewing the manufacturer's manual and also the IEEE standards on batteries. I don't remember the std number as it has been a number of years since I dealt with batteries but there may be a inspection sheet in those that you can use.
At the nuclear plants I worked at we used the DMA...
It sounds as if the issue is that the main breaker on the 15kV switchgear is not coordinating with the feeder breakers in the instantaneous region. What is the 30 cycle withstand of the main breaker? Did you look at turning off the instantaneous setting for the main breaker? Can the...
Are any of the motors fed by a VFD? It may be a non regen type so you could eliminate motor contribution from these. If you can't eliminate any conservative inputs and you can't find higher rated equipment, you may be left a CLR or replacing transformers with a higher impedance value. None of...
che12345,
This is an old switchboard made out of probably slate panels along with some newer board material. In it's original configuration, it probably had knife switches with fuses on the front of the board but they were replaced with breakers at various times, hence the breakers from...
Waross, I have continuity (about 0.2 ohms) and there are only 2 wires that go to wires wrapped around the pole pieces. When spin it with an electric drill I get varying voltages depending on the drill speed. The voltages are AC as expected as the two leads go to a Voltage Regulator. I suspect...
