Initial work on web based voltage calculator

powerweb/power_calcs.py

@@ -0,0 +1,39 @@
+#!/usr/bin/python
+
+voltage_limit = 11.5
+
+def calculate(cabletype, assumed_load, length):
+    cable_size = {
+        "13": 1.5,
+        "16": 2.5,
+        "32": 6.0,
+        "63": 16,
+        "125": 35,
+    }
+    single_phase = {
+        1.5: 31,
+        2.5: 19,
+        6.0: 7.9,
+        16: 2.9,
+    }
+    three_phase = {
+        1.5: 27,
+        2.5: 16,
+        6.0: 6.8,
+        16: 2.5,
+        35: 1.1,
+    }
+
+    drop = 0
+    if "/3" in cabletype:
+        drop = three_phase[cable_size[cabletype[:-2]]]
+    else:
+        drop = single_phase[cable_size[cabletype]]
+
+    total_drop = drop * assumed_load * length / 1000
+    max_length = (voltage_limit * 1000) / (drop * assumed_load)
+    r = total_drop / assumed_load
+    pfc = 230 / r
+
+    #print(f"Estimated PFC is {pfc:.1f}A")
+    return drop, total_drop, max_length, pfc