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 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
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...
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 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...
I am looking for some definitive write up on the use of fire rated PVC jacketed cable versus other types of fire rated jacketed cable. I need to know the differences in toxicity levels during combustion and also corossivity levels of gasses given off during combustion.
Thanks.
[yinyang]
