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--- ve.bus:manual_parallel_and_three_phase_systems [2019-10-01 13:33] – guy_stewart
+++ ve.bus:manual_parallel_and_three_phase_systems [2019-10-27 02:23] – [A continuous, unbroken negative link must be maintained between all units] guystewart
@@ Line 50: / Line 50: @@
 For DC, one fuse per phase is best. If a big single fuse is not available, use one fuse per unit. Same type of fuse due to same resistance.
-Beware of phase rotation between the inverter and AC in. When wired in the wrong rotation, the system will not accept the mains input and only operates in inverter mode. In that case swap two phases to correct it.
+Beware of phase rotation between the inverter and AC in. When wired in a rotation that is different to the programming of the Multis, the system will not accept the mains input and only operates in inverter mode. [[https://www.victronenergy.com/live/ccgx:start#phase_rotation_warning|If a GX device is connected, it will signal a phase rotation alarm]]. In that case swap two phases to correct it, or re-program the units to match the wiring rotation.
 Note: Do not over-dimension the AC cabling. Using extra thick cabling has negative side effects.\\
@@ Line 56: / Line 56: @@
       * Using 2 units (A and B) parallel and using extremely good cabling one might achieve a total resistance for Unit_A of 0.0001Ω and a total resistance for Unit_B of 0.0002Ω. This results in Unit_A carrying twice as much current as Unit_B although the resistance difference is very small.
       * Using the same 2 units in parallel with bad AC cabling one might end up with a total resistance for Unit_A of 15Ω and a total resistance for Unit_B of 16Ω. This results in a much better current distribution (Unit_A will carry 1.066 times more current than Unit_A) even if the absolute difference in resistance is much bigger than in the previous example (1Ω vs 0.0001Ω).
 ==== A continuous, unbroken negative link must be maintained between all units ====
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 If units need to be isolated at both poles, or local wiring requirements demand double pole isolation for each unit, the communications cables must be removed first AND appropriate safety signage needs to clearly explain this.
-Double pole isolation of the system is allowed (and sometimes required), as long as it at the battery connection end of the DC bus, and the Quattros remain with continuous negative between themselves.
+Double pole isolation of the system is allowed (and sometimes required), as long as it at the battery connection end of the DC bus, and the Multis/Quattros remain with continuous negative between themselves.
+==== Theory and background information ====
-Theory and background information on wiring is further explained in these presentations:
+wiring is further explained in these presentations:
   * {{:ve.bus:4._ripple_in_a_ac_battery_system.pdf|presentation - DC Ripple}}
   * {{:ve.bus:rva_-_theory_on_wiring_large_systems.pdf|presentation - Theory on wiring large systems}}'