110 vs 220 power question

[Boatsb]

The point was 60 is less than 50.

As an aside the 50 / 240 volt is not the same as 2 120 services.

It has a single neutral that could not handle 2 x 50 (100) amp loads .

 

[Avenger]

Because 2X 120V @ 50A is 100A. Either that or 2X 120V @ 30A is not 60A. And yes the neutral can handle it if they're on opposite phases which 240V 50A is by default.

 

[Boatsb]

Because 2X 120V @ 50A is 100A. Either that or 2X 120V @ 30A is not 60A. And yes the neutral can handle it if they're on opposite phases which 240V 50A is by default.

2 x 120 volt 50 amp is not the same as 220v 50amp. The opposite phase of the 220 is the key.

It means less than 50 amps on the neutral. With a balanced system the neutral cancels out.

 

[Avenger]

2 x 120 volt 50 amp is not the same as 220v 50amp. The opposite phase of the 220 is the key.

It means less than 50 amps on the neutral. With a balanced system the neutral cancels out.

I never said it was, but when you split the phases of 240V to power 120V equipment it becomes 2X 120V @ 50A which is more power than 2 30A circuits.

Now that we're all in disagreeable agreement about something we all agreed on in the first place let's move on. Agreed?

 

[Boatsb]

Yes. But it's dependant on the 2 phases being correct.

 

[Avenger]

If you have 240V service the phases have to be correct or you'd have 120V service.

 

[Boatsb]

Kind of.

First it's supposed to be 240 volt. Many times you get 208 from 3 phase power. That's not the same.


Also there is 125 volt 50 amp cords. Y cables and uneducated owners rewiring things. That explains the boat fires.

Remember that a drop in voltage is dangerous, a transformer can correct the voltage but it costs amps. That could leave you down 10%.

 

[Walter P]

So Scott, You're saying that by my having a voltage booster between my boat inlet and the dock
has cost me amps. I guess you're probably correct but I never have everything on (4 AC's, stove,
water heater, washer/dryer etc) at the same time. Actually it never occurred to me to try, but I have
never had a breaker shut off so it seems all is OK. Funny thing is that when we are away from the dock
and on generator power, I don't need the voltage booster and I get the prescribed voltage.

Walt

 

[MikeP]

I'd have to look at the schematics to be positive but I don't think the isolation transformers are in the circuit when the generator is selected - there would be no functional reason for them to be. So the transformers have no affect on Genny power and, if the genny is working properly, it will supply 120/240 VAC and more current capability than the 240/50A shore power circuit. So what you are describing makes perfect sense - problems on low voltage dock power/no problems on genny power. We have had that happen at a nearby marina on several occasions.

FWIW on 240/50 we occasionally pop the shore breaker if we are running the two big ACs (salon/gallery) plus a few other items and the water heater activates or I turn on the block heaters (1500W each). The Genny will run every electrical component on the boat at the same time, including all ACs, all stove burners, oven, washer, dryer etc, etc

 

[Boatsb]

So Scott, You're saying that by my having a voltage booster between my boat inlet and the dock
has cost me amps. I guess you're probably correct but I never have everything on (4 AC's, stove,
water heater, washer/dryer etc) at the same time. Actually it never occurred to me to try, but I have
never had a breaker shut off so it seems all is OK. Funny thing is that when we are away from the dock
and on generator power, I don't need the voltage booster and I get the prescribed voltage.

Walt

The boost of voltage is a trade off . Watts are watts. When you boost the voltage the watts stay the same minus and small loss. The amps is watts divided by volts. Higher volts is lower amps.

 

[SKYCHENEY]

Generator power does not pass through the transformer.

 

[Boatsb]

Generator power does not pass through the transformer.

Unless Bubba screwed it up. There's no reason to run it through a transformer if it's the right type of generator .

 

[Avenger]

Right. You don't want to be pulling two legs off a three phase generator and only getting 208V.

 

[Boatsb]

Never underestimate Bubba if he thinks he's saving a buck.

 

[Avenger]

Well, there's a lot of truth in that. In fact there's a very non PC phrase to describe that. I just think we've way outrun the OP's question.