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3 Phase supply Answered

What will be configuration to supply 3 Phase 460 V power into these strings having voltage range as shows in the pics. It can be either star, delta etc configuration. It should be balanced. Answer will be highly appreciated.


Jack A Lopez

4 weeks ago

Um... it kind of looks like it is wired correctly, if I can make some assumptions.

Assumption 1: Part of Picture 1 has been cut off. So I can only see 2 of 3 strings, each of which is named, "FLOOR HEAT STRING TYPE 1". I am assuming the missing string is identical to these two, and it should be wired between pin 7 of the relay, and the neutral line, N.

Assumption 2: Picture 2 is actually a detailed view of each string in Picture 1, named "FLOOR HEAT STRING TYPE 1."

Note that if I add together all the voltages of each series element in Picture 2, I get:

(40 V) + (62 V) + (62V) + (62 V) + (40 V) = 266 V

Also note for 3-phase power, the line-to-line voltage is greater than the line-to-neutral voltage, by a factor of 1.7320508 = 3^0.5 = square root of 3.

If I multiply 266 V by 1.7320508, I get approximately, 266*1.7320508 ~= 460 V. So I am assuming 266 V is the line-to-neutral voltage, and 460 V is the line-to-line voltage.

Thus, those strings intended for 266 V across them, are right where they should be, wired from a line (L1, or L2, or L3) to the neutral (N). Also this arrangement is a wye. Looks like the letter, "Y". Might be what you call, "star".

It is balanced, if all three strings are identical, like the picture suggests.

Also assuming all these voltages are measured in an RMS sense, since they are AC.