Difference between revisions of "ACSecondarySystems"
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The boat's secondary electrical system is AC. In Europe it will be designed for 230-VAC single phase. In North America it will be either 120-VAC single phase or 240-VAC double phase. A manual switch in the Pilothouse selects "boat power" (inverter) or "shore power" as the power source, with automatic detection of the voltage and frequency of the shore power. In the boat, the green AC ground wire is connected to the Common Grounding Point – the white ground wire is left floating. AC wiring should be stranded copper, not solid or tinned, to better resist breaking from vibration. All AC light bulbs adjacent to metal, especially in the engine room, are protected as shock hazards. All AC outlets are equipped with ground-fault-circuit-interruption (GFCI) circuit breakers. | The boat's secondary electrical system is AC. In Europe it will be designed for 230-VAC single phase. In North America it will be either 120-VAC single phase or 240-VAC double phase. A manual switch in the Pilothouse selects "boat power" (inverter) or "shore power" as the power source, with automatic detection of the voltage and frequency of the shore power. In the boat, the green AC ground wire is connected to the Common Grounding Point – the white ground wire is left floating. AC wiring should be stranded copper, not solid or tinned, to better resist breaking from vibration. All AC light bulbs adjacent to metal, especially in the engine room, are protected as shock hazards. All AC outlets are equipped with ground-fault-circuit-interruption (GFCI) circuit breakers. | ||
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== Inverter/Charger == | == Inverter/Charger == | ||
Revision as of 13:39, 26 April 2016
ACAlternating current Secondary System
The boat'sSecond secondary electrical system is AC. In Europe it will be designed for 230-VACVolt alternating current single phase. In North America it will be either 120-VAC single phase or 240-VAC double phase. AAmpere (amp), SI unit of electrical current manual switch in the Pilothouse selects "boat power" (inverter) or "shore power" as the power source, with automatic detection of the voltage and frequency of the shore power. In the boat, the green AC ground wire is connected to the Common Grounding Point – the white ground wire is left floating. AC wiring should be stranded copper, not solid or tinned, to better resist breaking from vibration. All AC light bulbs adjacent to metal, especially in the engine room, are protected as shock hazards. All AC outlets are equipped with ground-fault-circuit-interruption (GFCIGround fault circuit interrupter) circuit breakers.
Inverter/Charger
A combination inverter/charger is attached to the house bank for generating AC when offshore, and/or charging the batteries from shore power when in port. Points to consider in an inverter/charger are:
- Peak power output
- Peak charging current
- Continuous charging current
- Battery size AHAmpere-hours (A*H)
- Output voltage
- Output current regulation
- Safety factor of 30%percent
Shore Power
Operating on shore power almost anywhere in the world requires voltage conversion and frequency conversion.
AC voltage conversion is readily done with a transformer having multiple taps that can step-up or step-down a range of voltages. For a specific input voltage, the corresponding tap is selected manually or automatically. The transformer then delivers the correct output voltage.
This fits well with best practices. Although there are several ways of bringing aboard AC, the best way is an ABYCAmerican Boat and Yacht Council-approved isolation transformer between the shore power inlet and the breaker panel. This avoids polarization issues and doesn’t require a reverse-polarity indicator. AC shore power is brought aboard through an electrically isolated marine-rated receptacle in the side of the Deckhouse. A multitap isolation transformer meets this specification.
The incoming AC is grounded (green wire) at the shore end but is not grounded to the hull. Frequency conversion may or may not be critical. Most modern electronic equipment is designed for 50-60 HzHertz, SI unit of frequency, and should operate without difficulty (check the label).
The problem areas are timing devices that reference the AC, microwave ovens and AC motors, including those in domestic refrigerators. AC motors designed for 60 Hz will run more slowly on 50 Hz, and tend to overheat. To avoid this, you can:
- Use DCDirect current motors only
- Put AC motors on the inverter power only, not on shore power
- Install a voltage- and frequency-converting inverter/charger
