I have a question regarding a ground application on a delta system. We bought a High Resistance Grounding system. We had a choice for a Wye(broken)-Delta or Zig-Zag transformer to create the neutral point. We chose the Zig-Zag for the added benefit of harmonics.
When we receive the unit we...
Team,
I'm really lost on how to determine the required protection columns for the UL Classification for FR3.
We are installing a 1000KVA 13.2 - 480/277 FR3 station type transformer next to building. Under NEC 450.23 we have met all the requirements for an UL install except for the Required...
Hello,
We are currently spec'ing out meters for different locations on our site and I started comparing Power Quality meters on the market today. I am currently looking at the Square D ION7650, Eaton Powerxpert 8000, Fluke 1750. The question is, does anyone out there have any good...
Hello everyone,
I was hoping to get input on a situation my site encountered last week.
System - VCP-W Breaker with ABB TPU relay. Distributes 13.2KV directly to 5 Oil Switches and a line up of MV Switches. Each of the Oil Switches feed to 1000KVA D-Y oil filled transformer. The MV switches...
Are these dry type transformers? If so open the covers and look at how the primary connections between the coils are connected. I've had this problem before when replacing a failed unit with a different manufacture in a main tie main 480 volt switchgear. I had the same voltage measurements...
If I understand this correctly, the CT was meggered on the primary side (36kV) at 1kv (assuming dc) and a value of 55Mohm was recorded.
Two problems. One if you did perform the test on the 36kV side. 1kv is to low of a test voltage for valid results. The test should of been conducted at 15kVdc...
See,
Calculations:
http://www.cda.org.uk/megab2/elecapps/pub22/index.htm
http://www.electrician.com/articles/ampacity.htm
http://www.timesfiber.com/techpdf/1075-tn.pdf
General Information:
http://www.stormcopper.com/design/ampacity.htm...
Its sounds like your on the right track. Your load is a phase to phase load, 208volts. Spliting the eight supplies between the phases is a good idea.
I'll just add that since you load is phase to phase you will not need a neutral conductor. A equipment ground conductor you will need.
You also...
you say the contactor was sized for the motor load only.
Maybe the engineer sized it for the transformer and motor coming on at the same time. That would almost double your contactor size.
Only thing I would recommend is test or at least operate the low voltage circuit breakers. Thus insuring that the protective devices work and the breakers operate correctly, mechanically.
As for the low voltage feeders. This can get very time consuming. Example, from your post you mentioned...
As a field service engineer, in my part of the world Caterpillar is highly recommented. Off hand I can think of 5 hospitals that run Caterpillar units in my area.
As for the 2000KW units, I've had experience with 2 of them at one hospital. As a third party testing company we loadbanked the...
Getting info on you loading could be performed a couple of ways. One you could get a testing company to monitor the loading conditions. This should be performed for a 30-day duration. Or you could call the utility and ask for the last 12-month billings. On the billings it should have the power...
This may help. If you are looking for a test set to give you a capacitance. You may what to use a Biddle dissipation factor test set. I only suggest this because it is what I'm familiar with. I do believe that the doble uses that same concept though. The normal tests run will give a capacitance...
