I need to choose and deploy a simple PLC. It will have about 10 digital inputs and 10 digital outputs, split between two specific locations. The main & remote locations will be connected by 100baseT and RS-232, carried by some fiber converters we're using.
It would be nice to also be able to...
I've not found a suitable remote propane tank level gauge. The propane tank industry seems to sell them with built-in cell phones, to call them; not very useful when you want a local readout....and there's no cellphone coverage.
I do find <http://www.rochestergauges.com/Pages/PDFs/R3D.pdf> &...
So from what I've read, when you have a generator or other alternate power source, and transfer switch, each is a SDS, and that switch should switch the neutral as well. Neutral is grounded at the source.
But the case I'm looking at will have a utility xfmr w/wye secondary at the transfer...
In a new residence being planned, we'll have a:
"MSP Meter/Main Service Panel 200A 277/480V 3PH 4W"
that will feed a 200A 3ph/4W transfer switch; choosing between the grid above and a backup source. We have no need for any loads on the PG&E side of the transfer switch, save one: VT's & a...
In a new residence being planned, we'll have a:
"MSP Meter/Main Service Panel 200A 277/480V 3PH 4W"
that will feed a 200A 3ph/4W transfer switch; choosing between the grid above and a backup source. We have no need for any loads on the PG&E side of the transfer switch, save one: VT's & a...
I found a 4.25" three-phase ammeter at a hamfest today, and bought it for a song.
Unlike much of the things I buy, I have an immediate use for this.
It has 7-segment displays for all three phases, some alarm limits & will show neutral current. It mounts in 3.97" circular hole. It's got a...
In 2004, a PhD student was electrocuted in NYC by a hot junction box cover. I was quite interested in the case because a friend's Seeing Eye dog was similarly killed (in another city..) a day or two later.
Jody Lane's family settled with ConEd by establishing a foundation in her name...
Does any vendor still sell resistive reduced voltage starters? I seek same to limit inrush surge on a large transformer.
This is 3 phase 208, FLA of ~50A application.
Thus far, I can't find a source: be it new, NOS or refurb.
Many vendors have tried to sell me SCR-based "soft-starters" but...
I'm looking for case studies on propane vs. diesel costs in a standby power application of 15-25KW.
Obviously, the relative fuel costs will favor diesel, while the initial purchase & lower maint. costs favor propane. At some # of hours/year, the lines cross. My goal is get some numbers to...
This story is a good reminder that out in the field, not all the problems you have were covered in school/training/ops manuals:
http://cityroom.blogs.nytimes.com/2009/04/22/hootie-and-the-parakeets-round/
ConEd has ongoing issues with the Queen's wild parrots, who love warm places to nest...
First, I appreciate my fellow's engineer's patience on what, to people who build MW power systems, must seem like a gnat's worth of watts.
Here's another view of the proposed system. The issue is the backup inverters do not supply 277 P-N, just 120V. So to feed the long cable, we need a step-up...
The electrician planner has spec'ed a 112.5kva 480 delta:208/120 wye transformer. This is to handle the house and pool loads. This is a challenge but allegedly not impossible to also feed from the limited standby power.
I was debating in my head the pros & cons of instead having say a ~75kva...
Was reading <http://www.eng-tips.com/viewthread.cfm?qid=272481&page=1> with interest.
Has anyone dealt with transformer startup surges & inverter sources?
This installation shall have a 112.5 kva 3ph 480:208/120 transformer at the house, about 1000 ft. away from the utility building (feed)...
I have two proposals offered to carry 480 Delta/200A service about 1000 ft. to a 208/120v destination.
One uses a 480:4160v 112.5 KVA transformer at the meter, 3*#6MV-105 cable, and a 4160:208/120Y transformer at the house.
The other approach uses 3*250 MCM cable to carry 480, & one...
Givens: planned large residence, incoming 480V Delta service, poor ground conductivity [2nd hand/anecdotal report.]
The property will have a house and a 1000 ft distant shed. The outbuilding will have the incoming service/meter; the house will then be fed by onward CPE buried cable.
Each...
There are dozens of resi. 240VAC heat pumps in this area with the "at the unit" disconnect being a pull block.
You pull the phenolic chunk with 4-prongs out; and the unit is dead until you replace it.
Are they still legal for new installations; and if so, what are they formally called? I've...
I'm an EE helping a homeowner planning a new residence in CA. The property will be fed with 4160v/20A, and we'll have a grid-tie solar array, backup inverters & generator. The house will be fed with 208/Wye.
I'm trying to SWAG ideas & prices before he goes to the local PE for a legal design...
I'm seeking a {brand} name for the protective sock that goes inside polyethylene fiber duct. It's a woven hollow tube; you pull in say 6 of them, then the fiber is pulled down the middle of each sock. This not only protects fiber from abrasion but also tangles with adjacent fiber bundles.
I can...
[This is hardly a sure hit as the best forum, but it is communications.. if no answers, I'll try another place..]
I'm seeking a {brand} name for the protective sock that goes inside a polyethylene fiber duct. It's a woven hollow tube; you pull in say 3 of them, then the fiber is pulled down the...
I'm an EE working on a planned multistory 3800ft^2 residence in Northern CA.
The house must have sprinklers running off a single combined domestic/fire pump. I'm trying to SWAG the needed capacity for pump & power planning purposes. We are 6-8 months away from a sprinkler designer.
The house...
