This is probably a bit of a stretch, given that it's a pretty niche area, but I thought I would ask and maybe find that someone does have a suggestion.
I work as an Engineer for a university in their energy services division that provides several utility services to campus, including steam and...
We have an chiller / cooling tower installation that is using these new direct drive / permanent magnet motor application that requires a special VFD that runs at about 7Hz maximum speed. I do know that these were the first of this size in this application. We have three of these installed...
I have a question about an unusual installation. The current situation is as follows: 12.4KV utility service to a step down transformer that reduces the voltage to 4160V. The 4160 feeds a chiller VFD through a motor disconnect. We're looking at adding another variable speed chiller. One of...
A question has come up amongst some people in my department, for which I don't have an informed answer and I am hoping to get some opinions on the subject.
In a chilled water application, we have some buildings that have flow meters used for measuring the BTU usage. The meters are mostly...
This morning during a project meeting where we were discussing making some wiring modifications to our building, the question was raised as to whether or not it was permissible to run liquid tight (flexible) conduit into a distribution panel or if we would need to use rigid (we avoid EMT) and...
I have two questions regarding (non fusible) disconnects that I would like to ask:
1 - I have been told by a manufacturer that it is an NEC violation to add a fuse to a "non fusible" disconnect. Is this true?
2 - With a fused disconnect, for service entrance, do the fuses go up or down stream...
I have been looking at literature for on/off water detection sensors and I am looking for some opinions regarding which brands, or even products are decent. From looking through old eng-tips posts, I am finding (old - and yes I was around ET for the original depth of water sensing thread)...
Normally, I don't like to double post, but it was suggested that this forum may be a better place for my question, which was originally posted here.
I am experiencing some trouble with an ABB Mag Master, electromagnetic flow meter and I am hoping that someone with some experience might have...
I am experiencing some trouble with an ABB Mag Master, electromagnetic flow meter and I am hoping that someone with some experience might have some ideas as to what could be the trouble.
The meter is measuring the flow of water (ranging from 45-75 deg F - well within operating range) in the...
A search on the topic of negotiating job offers shows that is has been discussed here before, but it has been a while. Today I received an job offer that I had been waiting for.
The salary is within my acceptable range, but near the bottom of it. Based on the job postings, the offer appears...
Here is a question that is a varient on a common topic: backfeed protection. In a large, non pluggable, UPS, you are required to detect and stop any backfeed at the input voltage within a one second time frame.
My question is, how does one detect the presence of backfeed?
Measuring voltage...
This is a question for all the UL gurus, regarding a hardwired (not pluggable) UPS.
The magenetic devices in the UPS will cause leakage current through the UPS ground. I am trying to find out 1 - how much ground current is allowed, and 2 - what is the spec that applies here.
We have looked...
I am looking for two AC film capacitor, a 35uF at 370Vac, ~6.35A rms and a 70uF at 330Vac ~11.3A rms, with SCREW TERMINALS.
I have looked through the catalogs of several manufacturers, Cornell, GE, Aerovox, Mallory, Vishay, etc and while I am comming up with plenty of AC capacitors that are...
I was visiting a customer's installation that uses a building managment system to monitor the real time status of our equipment via modbus.
During my investigation, I discovered that the installation is wired with a combination of 45 Ohm cable interspersed with aproximately 6' sections of non...
Has anyone here ever dealt with this real estate / relocation company? If so how would you rate your experience?
Back in January I took a position with a company that required me to move to a different state. When I took the position I was told that they use this Crye-Lieke company to...
For the past couple of days, when time allows, I have been attempting to analyze the behavior of a PLL implemented in software that is used in some of our products. The PLL is modeled after a linear PLL in that it multiplies the incomming (sine) wave with a reference sine wave, filters (?) the...
Greetings All,
I am looking for suggestions for software analysis tools to help evaluate and analyze source code, predominantly written in C.
I have been tasked with managing a product development project, where the majority of the development will be done by an off shore team. From looking...
I was having a conversation with my boss the other day and he alluded to a concept that I wasn't familiar with: using two CTs in a series combination where the secondary of one CT sources the primary of another.
Now, I can understand where one might do this in really high current applications...
All,
I have been dragged into a problem at work that is a bit over my head and I am hoping that some of you could help shed some light on it for me. The problem relates to our motor soft start controllers. The production test department has learned that there is an apparent problem with...
This morning I turned down an offer from a company that would have involved relocation. There are several reasons for turning down the offer, some of them financial, some not, but one of the sticking points was amount that they were offering to relocate.
In this instance it would have been a...
