Harris Institute of Technical Training

Can a Form 9S meter a 3 phase 3 wire DELTA service?

Hey DW thanks for the question,
This connection at the meter will only use two of the three meter elements [the element where the meter brain is (if it is solid state) and one other element]. The meter potential coils in the two elements will be energized at the voltage of the 3 phase, 3 wire DELTA service so make sure the voltage rating of the meter is correct. Connecting the Form 9S meter and using two elements is a practice that has been done in the past with electromechanical meters and even though you would only use two meter elements (any two with an electromechanical meter) the potential coil of the third element would need to be energized at its rated voltage (the voltage of one of the other metered elements) with no current in that current coil. This would have also provided power to a demand motor if it was connected in the element that was not being used.
If you have other questions please let me know.
Thanks and Be Safe All Ways,
Brad

Gotcha I see how it works now. The company I work for uses 6S and 9S for 4 wire and 5S and 45S for 3 wire. That's the bad thing about being out of the field and not actually performing hands on, you forget some stuff.
Thanks
Dennis