I am working on a ground o/c coordination and i am having a bit of trouble on the wye-resistor grounded wye-solid grounded with delta tertiary transformer. Solidly grounded is connected at 230kV while the resistor grounded (50ohms) is connected at 34.5kV. Now, my questions is:
1. Will a ground...
the subject is 3-100kVA, ungrounded wye-delta transformer bank, 2400/4160Y-240/480V. During a spot check-up on this bank, we were surprised with the line-ground voltages 302V/320V/198V that were measured between the secondary terminals and the tank equipment grounding (as ground point). thinking...
Hi,
I would like to be "enlightened" on the basic Code requirements about motor overload protection.
1. What is the rationale with the now NEC requirement of having 3-Overload relays for 3-phase motors, versus the then allowed 2-overload relays for 3-phase motors.
2. What's the reason behind...
