We have several 6.9kV - 480V (delta/wye) transformers. These transformer neutral bushing CTs are sized at 2000/5 to which we tie to a 51G relay. However, I need to understand the basis for sizing such a CT as the potential phase to ground current (in the event of a ground fault) would far exceed...
I have a question to which I hope one of you can provide insight.
I have a U.S. client who wants to know how to ground the MV cables in the MV contactor compartments so he can comply with the NESC when he does maintenance on the MV motors.
For Switchgear, we have the ground and test devices...
We queried the vendor and they responded that this was in the normal range. I had my doubts and therefore my question. The CT's and readings all checked out fine and motor temperature was O.K. also.
We are testing out a pulverizer motor (800 HP @4.16kV) and it is running uncoupled. The amperage reading is about 80% of the rated FLA. This seems high to me and was wondering what the rule of thumb (if any) regarding comparing the running current coupled versus uncoupled?
Thanks
icelad,
Thanks for your views. You state that you took the PE exam with the experience option. I would like to do that, but hesitate to go throught the work of getting 5 PE's to sign an affidavit and forward to the board for a review in hopes that they allow me to sit for the test. Was it a...
Thanks, but the issue here is why would a seperate disconnector be required local to the controller if the disconnecting means for the motor which is not within sighr (proper lockout/tagout procedures in place and with qualified personnel)and will cut the power supply off to the MOV entirely. I...
This question concerns compliance with Article 430.102(A) for disconnecting means for a motor controller where the controller is integral to a component such as an MOV, yet the disconnecting means resides at the MCC and not within sight and when opened will disconnect power to the motor and...
Dear Associates:
I am a non degreed engineer working for over 30 years in the business starting as a draftsman and working my way up to a front line mangement position. I have had a degree of success I am proud of, but would get some self satisfaction by getting a degree. Given the fact that...
A further question regarding the application. I am finding that the form to take the test may be more daunting than the test itself!! I need to show 12 years of progressive, qualified engineering experience and this needs to be either while under the tutaledge of a PE or if not I will have to...
DanDel- Let me say that I have discussed this matter with several of my colleagues and they all inform me that the FE is more difficult than the PE given the fact that it is so broad based in its format. Furthermore, my state will allow me to sit directly for the PE without the FE - if I prove...
I noticed that some of you have recommended the Potter book that is sold on the ppi2pass.com website. The website notes that this book is not set up for the new "breadth and depth" PE exam format. However, I was at my local library and borrowed the latest edition of the...
I stared in this business almost 30 years ago as an Electrical Draftsman. I am now an Electrical Engineering Supervisor on a large project managing other designers and engineers. I wish to keep my upward mobility and eventually move into Project Management. I have a major problem. I do not have...
I realize that the length of the tap is a qualifier in the NEC, my question was if this same type of tap rule exists in the British WIring Regulations. Nonetheless the tap in question is around 25 feet.
I am reviewing an existing installation in the U.K. Presently there is a 1000 amp feed to an MCC. Prior to entering the feeder breaker of the MCC, there is a cable tapped off the feeder and services a 160 amp breaker which in turn acts as a main to a distribution panel. The tap is sized for the...
