One (1) new 2000A bus, 1200A VCB, 3P, 3W, 60Hz, 50kA, 2sec vertical feeder section will extend each bus of my existing 4.16kV double ended metal-clad switchgear model PowlVac® manufactured by Powell Industries Inc. to feed the two (2) new 4.16kV, 1200A, 3P, 3W, 60Hz, 50kA, 1sec metal-enclosed...
In this system the primaries of distribution transformers form a loop. The loop circuit start from the substation bus-bars, makes a loop through the areas to be served and returns to the substation. The circuit provides for quick restoration of service in the case of transformer or feeder fault...
Contact the vendor rep of the existing GIS if you know the manufacturer of the equipment. You have to have data sheet and SLD of existing GIS to get conservative quotation of one additional bay unit.
Your last paragraph is the present situation of the connection of the two incomer feeder cable of our ATS. We used the emergency generator as normal “N” (preferred) power source-1 of ATS and we used the utility grid as emergency “E” (alternate) power source-2 of ATS base on facility existing...
Thanks waross, to describe more of my question in my first post, our local standard state that critical security system loads should be supplied by emergency power regardless of how emergency power is defined in NEC or IEEE. My question was if we swap the two feeders does it impact the existing...
This question is mainly in regards to consequences. I have a 480VAC open transition Automatic Transfer Switch (ATS) to put in service soon; and I'm wondering what happens if we designate single ended 480V switchgear SG-002 fed from existing upstream generators as normal “N” (preferred) power...
As per our project specification, it state that “Space” – is a switching assembly locations which are not be equipped with a switching device but shall be developed to accept, with no modifications other than the installation of devices within the compartment door, a switching device suitable...
Thanks jraef,
Our vendor offer indicate that space bucket do not have door interlock such that if there is an accident happen due the reason of accessing the space bucket live parts by opening the shutter will void the warranty of their supplied equipment.
Does the above statement acceptable...
For an "SPACE" bucket in MCC, does UL 845 requires to be equip with automatic or manual shutter. Or a cap plugs is suffice to cover the stab opening of vertical bus?
See below sample of Vacuum Circuit Breaker sizing. While the demand load current is only 335.26 Amps, the selected VCB rating is 1200 Amps.
Actual application rating of Vacuum Circuit Breaker depends on the CT ratio and the relay settings.
Vacuum Circuit Breaker (VCB) is electrically...
Don't confuse the derating factor for multicore cables touching each other (as illustrated in your sketch) with the installation of multicore cables which are laid in several layers on the same tray, I mean does your standard in cable installation allows you to lay low voltage multicore cables...
1- Ampacity calculation and cable sizing can be as per NEC, or from the tables in IEEE 835, or IEC 60364, and IEC 60502-2.
2- Cable derating factors of ETAP or CYME can be use to calculate ampacities, as an alternative to the NEC, IEC or IEEE 835 tables.
3- Soil temperature is 40°C. The soil...
@rcwilson, thanks for describing clearly the control operation philosophy.
- When you said the lockout relay contacts (with 125VDC coil voltage) to energize the block transfer relay (with 24VDC coil voltage) in the ATS. Would that be OK. The 24VDC coil of inhibit transfer relay in the ATS is...
OK guys hopefully attached diagram is clear by now. Sorry for attaching truncated images.
http://files.engineering.com/getfile.aspx?folder=309f8d26-6698-4891-92f1-43d0b9b09204&file=Clear_E1L_Diagram.jpg
I attached clearer picture of the control diagram.
When fault occur at feeder CB in SG-002, the 125VDC 86 LOR located at MCC will trip and lockout. The 125VDC 86 LOR will block transfer and re-transfer control operation of 24VDC inhibit transfer relay located at ATS...
The 24VDC contact of relay will melt when block transfer and re-transfer operation of Automatic Transfer Switch due to the trip and lockout in the 125VDC 86 LOR. Would this be the case?
waross also pointed out there is issue of differing 24VDC and 125VDC relay coil voltage and failure to clear...
