Combine 3 x single phase/220v = 3-phase power?

[rolf.nielsen]

I have a 3-phase shore power connection to my ship. It needs all this power to run all systems onboard. Sometimes I dock where I can only get standard single phase/220v connections, and then I can't connect my shore power.

How to solve this? Is it possible to take 3 separate single phase/220v cables from the shore and combine these into the ship's needed 3-phase power? I understand that I can get phase converters that convert single phase to 3-phase power, that would work except I need the 3 x 16a to power all systems onboard. Is it possible to get a phase converter that can combine 3 x 16a single-phase inputs into one 16a 3-phase output? Space is not an issue, it's a big ship. I'd like to make the modification as simple as possible so that I don't have to rewire the whole system.

Needless to say, I'll get a licensed electrician to install it, so this post is just for my background info and to have a reasonably educated conversation with the electrician.

Any advice or experience with this? Surely I'm not the only one with big power needs occasionally docking at berths with single phase supply only. And no, I do not want to run the onboard generator out of respect for the other folks in the marina.

 

[RupertW]

One extra difficulty you will have is that usually there is just one socket per berth so if you do have to take two or three sockets (if you can get it to safely work which I am not sure about at all) then you may find the next boat coming in may have to unplug one of your plugs. I have certainly had to do that more than once and alas been shouted at angrily by the person who needs two or three.

 

[rolf.nielsen]

I agree that's a potential concern, and then I'll of course unplug and run fewer systems onboard out of respect for my fellow sailors. I live on my boat and sail around the year, so I'll often have access to as many plugs as I like, however.

 

[halcyon]

I have a 3-phase shore power connection to my ship. It needs all this power to run all systems onboard. Sometimes I dock where I can only get standard single phase/220v connections, and then I can't connect my shore power.

How to solve this? Is it possible to take 3 separate single phase/220v cables from the shore and combine these into the ship's needed 3-phase power? I understand that I can get phase converters that convert single phase to 3-phase power, that would work except I need the 3 x 16a to power all systems onboard. Is it possible to get a phase converter that can combine 3 x 16a single-phase inputs into one 16a 3-phase output? Space is not an issue, it's a big ship. I'd like to make the modification as simple as possible so that I don't have to rewire the whole system.

Needless to say, I'll get a licensed electrician to install it, so this post is just for my background info and to have a reasonably educated conversation with the electrician.

Any advice or experience with this? Surely I'm not the only one with big power needs occasionally docking at berths with single phase supply only. And no, I do not want to run the onboard generator out of respect for the other folks in the marina.

Are you talking about 3 inputs to the boat from 240 AC, or 1 single 3 phase 240 AC ? 3 phase is a totally different animal to single phase.

Brian

 

[Graham_Wright]

How to solve this? Is it possible to take 3 separate single phase/220v cables from the shore and combine these into the ship's needed 3-phase power?

No! You need a converter. But if you need 3 phase at 16A, you are going to need more than 16A from single phase.

 

[rolf.nielsen]

No! You need a converter. But if you need 3 phase at 16A, you are going to need more than 16A from single phase.

Agree and that's what I described. So the question is if it is possible to get a phase converter that can take 3 x single phase inputs and combine the power?

 

[Ian_Edwards]

Hi, I'm not sure how much you know about 3 phase power, but some basic might help, each phase is 120 degrees out of phase with the other 2 phases, and the phase to phase voltage is 415 volts, phase to the centre (ground) is nominally around 230 to 240 volts.
If your boat is wired for three phase, it is likely to have 3 seperate AC circuits, designed so that the load is balanced between the phase.
On a typical pontoon, I'm guessing, that in most cases all the sockets will be on a single phase, different pontoons being on different phases so the marina as a whole is a balance load. But they might be connected so that adjacent sockets will be on different phases. Someone will no doubt correct me on this point.
You can't just parallel up three 16amp sockets and assume that they are all on the same phase.
To generate a 3 phase supply from a single phase, you can either use a rotary converter, or rectify the AC to DC and the run three separate, synchronised (120 degrees apart) inverters to get back to 3 phases.
It might be possible to connect three different 16amp sockets to the 3 separate phases on your boat, by intercepting the wiring at the appropriate points, this might put all 3 of your circuits on the same phase , you'll need an experienced electrician to do this). This won't worry your electric kettle or microwave, but would be seriously expensive new for any three phase devices you may have, big electric motors for example, wouldn't spin.

 

[halcyon]

I agree that's a potential concern, and then I'll of course unplug and run fewer systems onboard out of respect for my fellow sailors. I live on my boat and sail around the year, so I'll often have access to as many plugs as I like, however.

Yes but are you talking about 3 x 240 VAC single phase input sockets ? or 3 phase 240 VAC system, 3 phase mains is totally different.

Brian

 

[ip485]

Apologies for the thread divert but I would be interested to know why your boat is wired for three phase out of technical interest. Mine takes 32 Amp of which most marinas have a few and that enables most systems to be run at the same time. I assume you need to draw more power than that for peak load, but perhaps there are certain systems that you need to run and will not run without a 3 phase source? I assume your Generators are 3 phase?

 

[Graham_Wright]

Hi, I'm not sure how much you know about 3 phase power, but some basic might help, each phase is 120 degrees out of phase with the other 2 phases, and the phase to phase voltage is 415 volts, phase to the centre (ground) is nominally around 230 to 240 volts.
If your boat is wired for three phase, it is likely to have 3 seperate AC circuits, designed so that the load is balanced between the phase.
On a typical pontoon, I'm guessing, that in most cases all the sockets will be on a single phase, different pontoons being on different phases so the marina as a whole is a balance load. But they might be connected so that adjacent sockets will be on different phases. Someone will no doubt correct me on this point.
You can't just parallel up three 16amp sockets and assume that they are all on the same phase.
To generate a 3 phase supply from a single phase, you can either use a rotary converter, or rectify the AC to DC and the run three separate, synchronised (120 degrees apart) inverters to get back to 3 phases.
It might be possible to connect three different 16amp sockets to the 3 separate phases on your boat, by intercepting the wiring at the appropriate points, this might put all 3 of your circuits on the same phase , you'll need an experienced electrician to do this). This won't worry your electric kettle or microwave, but would be seriously expensive new of any three phase devices you may have, big electric motors for example, wouldn't spin.

You are assuming he doesn't have 3 phase machinery.

 

[KLBH]

Yes you can get inverters with single phase input giving a three phase output but it maybe expensive at the powers you are talking about.

 

[halcyon]

You are assuming he doesn't have 3 phase machinery.

We have been trying to find out since #4, cannot get an answer.

Brian

 

[Ian_Edwards]

You are assuming he doesn't have 3 phase machinery.

No, a rotary or solid state single to 3 phase converter will power 3 phase devices.
and I do say
"This won't worry your electric kettle or microwave, but would be seriously expensive new for any three phase devices you may have, big electric motors for example, wouldn't spin",
That's if you independently connect each phase on the boat to a seperate 16amp socket, and you don't know the phase of each of the three 16amp supplies.

I can't put a name to a company that produces a 3 phase converter that would, for example take 3 standard 16amp inputs of arbitrary phase and combine them into a synchronised 3 phase supply, but technically it is possible, each phase would have to be converted to DC, the 3 DC source would need to be summed, then 3 inverters, synchronised at 120 degree would be need to supply the required outputs.
The generator I run has a 3 phase multipole generator (magnets in the flywheel) the three phases are rectifier and combine into DC, which then runs a single phase 240volt regulated supply, but it's only 5KVA.

I would add the obvious, you can't get a quart out of a pint pot, if you connect a 3 phase converter to a 16amp supply you about 3.8kWatts out of it, or 1.2kWatts per phase.

 

[Bilgediver]

No, a rotary or solid state single to 3 phase converter will power 3 phase devices.
and I do say
"This won't worry your electric kettle or microwave, but would be seriously expensive new for any three phase devices you may have, big electric motors for example, wouldn't spin",
That's if you independently connect each phase on the boat to a seperate 16amp socket, and you don't know the phase of each of the three 16amp supplies.

I can't put a name to a company that produces a 3 phase converter that would, for example take 3 standard 16amp inputs of arbitrary phase and combine them into a synchronised 3 phase supply, but technically it is possible, each phase would have to be converted to DC, the 3 DC source would need to be summed, then 3 inverters, synchronised at 120 degree would be need to supply the required outputs.
The generator I run has a 3 phase multipole generator (magnets in the flywheel) the three phases are rectifier and combine into DC, which then runs a single phase 240volt regulated supply, but it's only 5KVA.

I would add the obvious, you can't get a quart out of a pint pot, if you connect a 3 phase converter to a 16amp supply you about 3.8kWatts out of it, or 1.2kWatts per phase.

Beware......Especially an Aberdonian where so many rigs have an American influence.... Your assumptions may be wrong....Let's find out if his boat is UK and in Europe or is it a USA boat or ship which may well may be wired Delta and not Star!!!!

Some Aberdeen service companies overlooked this this when dealing with our rigs.

 

[Graham_Wright]

No, a rotary or solid state single to 3 phase converter will power 3 phase devices.
and I do say
"This won't worry your electric kettle or microwave, but would be seriously expensive new for any three phase devices you may have, big electric motors for example, wouldn't spin",
That's if you independently connect each phase on the boat to a seperate 16amp socket, and you don't know the phase of each of the three 16amp supplies.

I can't put a name to a company that produces a 3 phase converter that would, for example take 3 standard 16amp inputs of arbitrary phase and combine them into a synchronised 3 phase supply, but technically it is possible, each phase would have to be converted to DC, the 3 DC source would need to be summed, then 3 inverters, synchronised at 120 degree would be need to supply the required outputs.
The generator I run has a 3 phase multipole generator (magnets in the flywheel) the three phases are rectifier and combine into DC, which then runs a single phase 240volt regulated supply, but it's only 5KVA.

I would add the obvious, you can't get a quart out of a pint pot, if you connect a 3 phase converter to a 16amp supply you about 3.8kWatts out of it, or 1.2kWatts per phase.

I guess you could do it mechanically - three separate single phase motors on a shared shaft or with a countershaft. Quite an installation though!

 

[sailorman]

Are you talking about 3 inputs to the boat from 240 AC, or 1 single 3 phase 240 AC ? 3 phase is a totally different animal to single phase.

Brian

I wouldnt want 415v coming into my boat

 

[Graham_Wright]

I wouldnt want 415v coming into my boat

It's a bit less now - 388 I think. However!

 

[rolf.nielsen]

My boat is Danish. I have 3-phase power supply, well, because the previous owner chose to set it up like that I suppose. I run the equivalent of a full household on that supply, including dishwasher, washing machine, dryer etc. I also run a 3-phase pump. So I need the power and I need the 3-phase supply.

Thanks for all your input. My take-away is that it is not easy (didn't expect it to be), but converting 3 x single-phase to DC, combining and then converting that to a 3-phase output could do the job (thanks Ian Edwards). I'll look forward to seeing what my electrician will recommend!

 

[halcyon]

My boat is Danish. I have 3-phase power supply, well, because the previous owner chose to set it up like that I suppose. I run the equivalent of a full household on that supply, including dishwasher, washing machine, dryer etc. I also run a 3-phase pump. So I need the power and I need the 3-phase supply.

Thanks for all your input. My take-away is that it is not easy (didn't expect it to be), but converting 3 x single-phase to DC, combining and then converting that to a 3-phase output could do the job (thanks Ian Edwards). I'll look forward to seeing what my electrician will recommend!

Still think OP has three single phase inputs due to high power usage.

Can you buy 240 AC three phase domestic equipment ? how many marinas have 240 AC 3 phase on the pontoon ?

Brian

 

[rolf.nielsen]

Still think OP has three single phase inputs due to high power usage.

Can you buy 240 AC three phase domestic equipment ? how many marinas have 240 AC 3 phase on the pontoon ?

Brian

I am OP. I have a 3-phase power supply. Some marinas, including mine, offer that kind of power supply on the pontoon. Others don't, which is why I'm looking to add the ability to take multiple single-phase power supplies as described.