I have an elevator motor that says exactly 'furnish a balanced, 3 phase, 3 wire electrical feeder system. I have a 240v, 3 phase feeder system in this building, a 3 phase high delta system tend to be unbalanced. Am I reading too much into this?? Does this need to be operated on voltages that can be balanced like 208. Even a 208v system can possibly be very unbalanced in some scenarios.
2023 NEC
Section 430.24
Several Motors or a Motor(s) and Other Load(s) (1) (2) (3) (4)
You can use 208 volt motors but you need 208 volt system. They balance same way.
A three phase 240 volt3 wire delta system is what you describe. It has no neutral conductor.
How many motors do you have?
It means that you must balance the motors on each line or "group" (phase).
You do not want to put the 208 volt motors on a 240 volt feeder or vise versa,110.4 Voltages.
Need compatible voltage for them.
Since they are all three phase motors then it will be easy to balance them.
Draw 3 horizontal lines and connect each motor to each line (phase).
Assume no other loads, only motor loads.
Use T.430.250 for 3 phase motors amperages.
Take the largest motor amperage times 125 % and the remaining motors at 100 % amperage.
Add them all up to determine the feeder conductors. Size per T.310.16 75 degree terminals for ampacity.
After adding them all you must
round down to determine the OCPD per T.240.6 (A)
For an example like this one I should sketch it out on paper for a better and more complete example.
For this reason I will not consider the required size of OCPD for the motors, which is unknown.
Thanks for reading.
TX+MASTER#4544