added star delta converter module (#9649)

* added star delta converter module

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* fixed typo

* Update star_delta_conversions.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* Updates star_delta_conversions.py

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* updated to handle ac impedances

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* updating DIRECTORY.md

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Christian Clauss <cclauss@me.com>
Co-authored-by: cclauss <cclauss@users.noreply.github.com>

DIRECTORY.md

@@ -525,6 +525,7 @@
   * [Resistor Color Code](electronics/resistor_color_code.py)
   * [Resistor Equivalence](electronics/resistor_equivalence.py)
   * [Resonant Frequency](electronics/resonant_frequency.py)
+  * [Star Delta Conversions](electronics/star_delta_conversions.py)
   * [Wheatstone Bridge](electronics/wheatstone_bridge.py)
 
 ## [File Transfer](file_transfer)

electronics/star_delta_conversions.py

@@ -0,0 +1,103 @@
+# https://www.electrical4u.com/delta-star-transformation-star-delta-transformation/#:~:text=The%20relation%20of%20delta%20%E2%80%93%20star,of%20the%20delta%20connected%20resistances.
+# https://en.wikipedia.org/wiki/Y-%CE%94_transform
+
+
+def star_to_delta(
+    impedance_a: complex,
+    impedance_b: complex,
+    impedance_c: complex,
+) -> list[complex]:
+    """
+
+    Convert's star impedance arrangement to delta
+
+    Examples:
+    1.) Impedance with resistances and zero reactance
+    >>> star_to_delta(complex(2,0),complex(1,0),complex(1,0))
+    [(2.5+0j), (5+0j), (5+0j)]
+
+    2.) Impedance with resistance and reactance
+    >>> star_to_delta(complex(2,0),complex(1,2),complex(1,6))
+    [(-3.5+12j), (8.2+7.6j), (3.702702702702702+1.7837837837837838j)]
+
+    3.) Zero impedance
+    >>> star_to_delta(complex(0,0),complex(1,2),complex(1,6))
+    Traceback (most recent call last):
+       ...
+    ValueError: entered impedance value is zero
+
+    4.) Negative resistance
+    >>> star_to_delta(complex(12,0),complex(-1,2),complex(1,6))
+    Traceback (most recent call last):
+       ...
+    ValueError: entered resistance value is negative
+    """
+
+    if abs(impedance_a) == 0 or abs(impedance_b) == 0 or abs(impedance_c) == 0:
+        raise ValueError("entered impedance value is zero")
+
+    if impedance_a.real < 0 or impedance_b.real < 0 or impedance_c.real < 0:
+        raise ValueError("entered resistance value is negative")
+
+    delta_arrangement = []
+    impedance_chain = (
+        impedance_a * impedance_b
+        + impedance_b * impedance_c
+        + impedance_c * impedance_a
+    )
+    delta_arrangement.append(impedance_chain / impedance_a)
+    delta_arrangement.append(impedance_chain / impedance_b)
+    delta_arrangement.append(impedance_chain / impedance_c)
+
+    return delta_arrangement
+
+
+def delta_to_star(
+    impedance_a: complex,
+    impedance_b: complex,
+    impedance_c: complex,
+) -> list[complex]:
+    """
+
+    Convert's delta impedance arrangement to star
+
+    Examples:
+    1.) Impedance with resistances and zero reactance
+    >>> delta_to_star(complex(3,0),complex(5,0),complex(7,0))
+    [(2.3333333333333335+0j), (1.4+0j), (1+0j)]
+
+    2.) Impedance with resistance and reactance
+    >>> delta_to_star(complex(1,3),complex(2,0),complex(0,-3))
+    [-2j, (3-1j), (0.6666666666666666+2j)]
+
+    3.) Zero impedance
+    >>> delta_to_star(complex(0,0),complex(1,2),complex(1,6))
+    Traceback (most recent call last):
+      ...
+    ValueError: entered impedance value is zero
+
+    4.) Negative resistance
+    >>> delta_to_star(complex(12,0),complex(-1,2),complex(1,6))
+    Traceback (most recent call last):
+      ...
+    ValueError: entered resistance value is negative
+    """
+    if abs(impedance_a) == 0 or abs(impedance_b) == 0 or abs(impedance_c) == 0:
+        raise ValueError("entered impedance value is zero")
+
+    if impedance_a.real < 0 or impedance_b.real < 0 or impedance_c.real < 0:
+        raise ValueError("entered resistance value is negative")
+
+    star_arrangement = []
+    impedance_sum = impedance_a + impedance_b + impedance_c
+    star_arrangement.append((impedance_b * impedance_c) / impedance_sum)
+    star_arrangement.append((impedance_c * impedance_a) / impedance_sum)
+    star_arrangement.append((impedance_a * impedance_b) / impedance_sum)
+
+    return star_arrangement
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()