Quote:
Originally Posted by foggysail
Yeah!!!!
... they MUST be isolated from the boat's grounding system.
Consider an electrical schematic that resembles the letter H where the load is connected in the middle of the bar in H.
+170V
__|__
| |
\ |
|-**-|
| \
|___ |
|
0 Volts
+170V
__|__
| |
| \
|-**-|
\ |
|___ |
|
0 Volts
This is the standard so called H bridge with the ** being the load. Notice that current each side of the load is alternately connected to 170V depending on which switch is closed and the switches close alternately at 60 times per second. NEVER IS THE OUTPUT TERMINALS CONSTANTLY TIED TO GROUND as house hold power is via its grounded conductor. IF you tie one side of your inverter's output to ground you create a short circuit and possibly destroy your inverter...
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This is incorrect. The bridge operates on the 'Hot' wire only. The 'Neutral' wire is a grounded conductor, as in household systems. In an Inverter/Charger, the transfer relay disconnects the ground to neutral bond when transferred to incoming power and connects it when inverting. In an Inverter only the G and N are permanently connected. In either case, the output neutral conductor must be kept isolated from the vessel neutral buss when any other source is providing power. Otherwise, a ground-loop will exist and current will flow in the grounding circuit. This is a portion of the load current which should all flow through the N wire but is finding a shared path through the improper G-N connection. Voltage produced by this fault current is impressed on underwater metal parts and causes corrosion and premature depletion of anodes.