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How to Convert AC Power for a DC Inverter

Configuring Power for a 220 to 120 Converter for a DC Inverter System: If I use the converter, is 27 amps within the tolerance levels for using a 10 amp power tool, that needs 30 amps on start up.

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Converting 220 Volt to 120 Volt
Electrical Question: Here is my situation. I am on 40 ft sailboat in Lima Peru. The country has 220 volt, 3 wire circuits. My tools are all 110 volt so I need to find out how to get power while my boat is out of the water (I know a lot of this stuff will be out of code. SO I understand that these are HYPOTHETICAL Questions, so you will in no way be liable. BELIEVE ME, there is not much of a code here). I realize some of these questions deal are more on a electronics side of thing, but I would appreciate any input.

Project Background:
1) Checking the breaker box.
I have found that they have 2 cables (Red & Black) that are carrying 220 volts each. These are tied into double breakers. Originally they told me it was a 4 wire system, with two 110 volt legs. Now when I need the power this is not the case. All the voltage supplied to the box is 220 volts, 3 wire. This is at the box. When checking an outlet, and I connect my meter from one of the hot leads across to ground, and I get 274 volts, when I use the other hot lead I get 99 volts. This equals 273 volts, yet when I check the two prongs on the outlet I get 220 volt. I don’t get it.

2) Converters.
Looking locally at the converters I am only finding converters (very expensive) for 3000 VA (Va, I understand is equal to watts at low power usage). This gives me 27 available amps ( 3000 Va / 110 volts). Some of my tools require 10 amps, and on start up, I understand that I should have 3 times the amps or in this case 30 amps. So I am hesitant to use a converter because of possible damage to my tools.

3) Existing Converter/Inverter.
I have a combination system that I use in conjunction with shore power, and my batteries on the boat. On batteries, the unit inverts DC power to 110 AC. When plugged into 110 volt shore power, the unit transfers power to the AC Receptacles, and also charges the batteries. The unit will accept 220 volts coming in, but will only act as a battery charger. It will not convert the AC power, not will the inverter work. Also there is no transfer of power.

4) Required Power or Ideal Outcome.
I need to be able to both charge the batteries, and have 110 volt AC power, with enough amps for my tools.

Thanks in advance for you help Dave.

This  electrical wiring question came from: Dave, in Lima Peru.
Thanks for your electrical question Dave.

Dave’s Answers to the Specific Questions:

Application: Convert AC Power for a DC Inverter.
Skill Level: Advanced. This electrical project is best performed by a Licensed Electrician.
Tools Required: Basic Electricians Pouch Hand Tools and a Voltage Tester.
Estimated Time: Depends on personal level experience, ability to work with tools.
Precaution: Identify the circuit, turn it OFF and  Tag it with a Note before working with the wiring.
Notice: Installing additional electrical wiring should be done according to local and national electrical codes with a permit and be inspected.

Configuring Power for a 220 to 120 Converter for a DC Inverter System

Specific Electrical Questions and Answers:

1) Is there a way to get 110 volts out of 220 volt 3 wire system?
I can either come from the box, or the outlet. I can not find anything on the web that tells me if it is possible to rewire/change breakers, to get 110 volts from a 3 wire 220 volts system. Common sense tells me that I need to use a convert since the power supplied is 220 volts. The local electrician tells me that I can get one leg of 110 volts, but the amps will be halved. Do not understand this.

2) If I use the converter, is 27 amps within the tolerance levels for using a 10 amp power tool, that needs 30 amps on start up.

3) How to wire the converter?
The converter has 2 black wires going into it, and 2 black wires coming out. Do I need to worry about which are positive or negative on the incoming/outgoing legs?

4) Can I use the converter to change the power into my inverter/combiner on my boat?
So if the converter comes in with 110 volt, pure sine, and 27 amps, and my combiner is rated to receive 30 amps, I am thinking that I can then use the electrical outlets on the boat to run power tools, and any deficiency in amps on start up, will be handled by the batteries.

5) Do converters going from 220 volts to 110 volts produce a pure sin curve?

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