Add py script for voltage drop calcs

power_calcs.py

@@ -0,0 +1,49 @@
+#!/usr/bin/python
+
+import sys
+
+cabletype = sys.argv[1]
+voltage_limit = 11.5
+
+cable_size = {
+    "13": 1.5,
+    "16": 2.5,
+    "32": 6.0,
+    "63": 16,
+}
+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,
+}
+
+drop = 0
+if "/3" in cabletype:
+    drop = three_phase[cable_size[cabletype[:-2]]]
+else:
+    drop = single_phase[cable_size[cabletype]]
+
+print("Voltage Drop (per ampere per metre): {}mV/A/m".format(drop))
+
+assumed_load = int(sys.argv[2])
+length = int(sys.argv[3])
+
+total_drop = drop * assumed_load * length / 1000
+
+print("Total drop at {}A over {}m is: {}V".format(assumed_load, length, total_drop))
+if total_drop > voltage_limit:
+    print("FAILED: VOLTAGE DROP TOO HIGH")
+max_length = (voltage_limit * 1000) / (drop * assumed_load)
+print("Maximum length of cable at this load: {}m".format(int(max_length)))
+
+r = total_drop / assumed_load
+pfc = 230 / r
+
+print("Estimated PFC is {:.1f}A".format(pfc))