There isn't a lot of hydrogen gas produced in battery charging unless the batteries are overcharged either by rate (current) or potential (voltage). This question of the fan and it's classification is answered in 2008 NEC Article 480.9(A). There will be relatively little volume of hydrogen gas...
I recently designed a system at a cement plant for a crusher with a liquid rheostat. I used Eletele at the recommendation of the cement plant. They already had one which worked well. Eletele was quite easy to work with and no real language barrier. www.eletele.com.br/Reostatos_e.htm
I...
Hi Mark!
Here is another research project, http://www.strayvoltage.org/stories/index.php3?Story=20010812_researchers.inc
and another http://edis.ifas.ufl.edu/AE019
I have seen similar problems in California but in the Tulare area, where most of the dairies are located, we have several good...
I don't believe that there is any specific load requirement for a convenience outlet for HVAC equipment. Therefore the air conditioning companies can list the load requirement of whatever transformer or fuse rating which supplies the convenience outlet. The only NEC imposed load requirement...
I haven't heard that term before but it may mean the same thing as "fail safe". To be "fail safe" if the wire to the interlock sensor was cut or if you lost power to the interlock sensor the power to the machine should be cut off. Of course there are other ways for the interlock system to fail...
I agree with waross in how he describes to connect the neutral to ground at the two different sources. I don't see why a 3 pole switch would be any more reliable than a 4 pole switch. I always specify 4 pole switches for a couple of reasons. One is that a 3 pole switch is not always...
Jasonarac
I just went through the "Event" CSV dump and it does not give a "phase reversal alarm". Typical alarm sequence is:
AC power has been restored
AC Restored Message sent to registered clients
Utility power has failed
UPS bypass unavailable
UPS switched to battery power
AC Fail Message...
alehman
A tap of a tap is a good way of looking at it. If the exclusion was introduced in 2005 as you say then perhaps georgeshall's installation was previous to the exclusion and therefore is acceptable as is but he still couldn't make the new tap.
Perhaps the reasoning for the exclusion is...
georgeshall brings up an interesting point with the
I didn't realize this but I almost never utilize 240.4(B) anyway.
I agree with georgeshall but I add that per the NEC articles he quotes your existing system does not meet code (your secondary conductors have less ampacity than the...
Jasonarc
I didn't see that alarm and the tech support guy with initials MN (who like I said was helpful and I called him to tell him that the problem was solved) told me that the BladeUPS did not have a way to check phase sequence and that is why the frequency measurement is in error. I...
If a mistake was made on first power-up sequence then you would have to go through the power up sequence again with the correct phase sequence. I don't know if this requires complete removal of the batteries or if it can be initiated through software. Remember this is a UPS so after initial...
My understanding in talking the Powerware UPS tech support is that the UPS does NOT care what the phase sequence is at the input, it just doesn't want it to change. Apparently at the application of power to the UPS it notes the phase sequence and expects it to remain that way. I don't think...
edison123, the UPS is for a small data room only but there were two three phase loads, both air conditioners for the data room.
The client's comment was that "this explains why the air conditioners never came on when we were on standby power". Apparently they never had a long power outage, at...
First I would like to say that I should have stated "We have a client who has a ...", not "We have a ...". I had just gotten a call to go out there the next day and I was in a hurry to post this to give time for answers before the next morning and also have time to call Eaton Tech Support...
I have been an engineer for many years and not paid much attention to phase sequence, just connected A to A, B to B, and C to C. Of course motor and equipment rotation direction is important.
To answer 521AB's question, PG&E (Pacific Gas & Electric Company in California) uses ACB sequence and...
