Gang, I have a question if such an animal exists, at least exist without the complication of a PLC, etc. The AHJ (USCG) s requiring that the fire pumps be outfitted with LVR controllers for obvious reasons. The existing plant uses LVP types but with additional remote start/stop from two...
We have three 37.5 kVA 480/120 single-phase transformers wired Delta-Wye to derive 208/120 at the secondary. At 37.5 kVA, the single-phase Voltage and Current at the primary is 480V x 78.125A. Configured in Delta, the Primary Line current is 1.732 x 78.125A = 135.3A - indicating a new kVA...
Does anyone know of testing standards governing the testing of lv power distribution systems. I have an industrial system presently fed from a DG plant and need to evaluate performance to determine what is needed for a utility service option. So I will be testing things like motor inrush, pf...
Gang, I have an application for a 50-meter 460 V cable run subgrade in ASSHTO class heavy grade precast concrete culvert with cast metal grate. The area is subject to periodic storm flooding to about 5 feet over grade. Many of the US cable manufacturers are telling me that their standard...
Wading through old, archived EE treatises involving the MVA method of performing short-circuit analyses and I came across a Delta to Wye conversion for two sources connected to a common bustie feeder (one source on each end of the bus-tie feeder) where the author computed "S/Y, where S is the...
I have an application in China where they are running 380 V 3-Phase for motors, etc and for the utilization receptacles, they are coming directly off the line phase to neutral for 220V without using a lighting transformer. The receps serve the standard items from coffee pots, office equipment...
Checking the archives I see several entries that makes sense - however, does not cleanly map to my circumstance. I am looking to parallel to a old (~1965) GE 480V, 3 phase, 6 pole, 1200 rpm generator. The stator shows 108 slots and a pole covers 14 slots. From what is written, the pitch is...
I can't seem to find a solid basis for the notion that I have been applying for as long as I can remember with regard to limiting the control voltage for hand-actuated devices to 120V. I am looking for an NFPA, OSHA, etc cite. I did find a reference in IEEE 45 that limits control voltages in...
thread244-427694
This is an old post - but ....UL used to have a "Marine Supplement" to accompany UL 2202 and this supplement was invoked by the USCG is handling on-board battery chargers. It included the added rubric governing corrosion, humidity, etc.
