Complex 240v 110v arrangement

Pgeee

Active Member
Nov 22, 2021
154
AUSTRALIA
Boat Info
Sedan Bridge 400 1996
Engines
Cat 3116
I am in Australia. My DB 400 has had a professional partial changeover to 240v. This was done as far as I can see by
A) taking out the port ac in socket and replacing with a 240v socket,
B) changing all the power outlets to 240v outlets, I assume existing cables were reused
C) adding a switch at the control panel to select 240v shore or 240v inverted from 110v at the genset
D) adding a 110v to 240v inverter to facilitate 240v sockets from genset

the downside is I don’t think port a/c 110v (vacuum , water heater etc) is ever going to work on shore power as it probably was totally disconnected from that circuit

But starboard a/c from shore power is perhaps viable with a fairly heavyweight 240v to 110v transformer connected to the starboard a/c shore power input. . The issue I would have with that is would all the starboard items work ok on 110v 50hz. The fridge transformer I think will be ok, the cruisair a/c maybe? , the a/c water pump not sure, stove probably ?

all 110v stuff works fine on the genset

I’m interested in learned opinions . If an expert comes back I’ll have questions on water heater and charging also
 
There have been a number of us who have either converted or are thinking about it.

Not sure about your power system down under, but you’ll have to post your AC system to get into the details.

However, with a 120/240 system, you should be able to power both 120 and 240 appliances, with limitations.

you could also convert your water heater to 240V.
 
I work with international data centers that are 240vac quite often.
We have three wires for 240 volt Hot-Neutral-Hot plus ground; H to H is 240, either H to N is 120v (which you don't have now)

The outlets can be converted easily as you noted because in a 240v country you use no "neutral" third wire like we do in North America. The existing two wires plus ground can be used for a 240v outlet.

As noted by @dtfeld the water heater can be converted to 240v simply by getting the correct 240v element locally. 50Hz will not matter it's just a big resister.

The vacuum I would just get a similar sized head from a 240v shop vac and swap it out.

The fridge depends on the make/model again. If it is really a 12v compressor. And just front ended with a 120v-12v power supply you could just swap out that supply with a 240v to 12v.


Now in item C) you say 240v from the generator, but D) "using a 120v to 240v inverter".
That's a bit odd all you normally need is a step up "transformer", no electronics required, but it may be at 60Hz if the generator is an NA model.
240v at 50Hz? Pictures can always help.

Now if your generator is also a NA unit it may have the option to change the terminals for true 240v instead of 120v we would need the make and model to look it up. It may even be able to put out both 240 and 120 as in NA but likely at 60hz. The frequency is controlled by speed of the engine, the governor could be adjusted to lower the rpm slightly. The problem that may arise there is if it has electronic voltage regulator with frequency monitor it needs be set to 50Hz or it will think the 50hz is caused by an engine under speed/overload. Replacement 50hz regulators are often available.

Assuming a 240v to 120v step down transformer, 50hz vs 60Hz: motor loads like A/C and refrigerator. Check the name plate ratings they may even be built for both. Motors will run a bit slower, use a bit more amps, and run hotter but may be alright you would need to monitor them carefully at least initially. An IR temp gun would be essential.

Things like a microwave would likely be best to just get a 240v locally.
 
There have been a number of us who have either converted or are thinking about it.

Not sure about your power system down under, but you’ll have to post your AC system to get into the details.

However, with a 120/240 system, you should be able to power both 120 and 240 appliances, with limitations.

you could also convert your water heater to 240V.
Thanks, i'll try put together a diagram. I am pretty sure I can get everything where I want it as long within the obvious constraints I have (i.e no 110v port shorepower socket) using a 240v to 110v transformer. But this will turn 240v 50hz into 110v 50hz . US devices often expect 60Hz. Some devices will go haywire if they don't have the correct hertz so it's a case of working out which will and which wont spit the dummy. For instance the label on the control box for the Cruisair A/C seems to indicate it's happy with different voltages, but the compressor itself says 115v at 60Hz, but 100v at 50Hz, which infers a voltage drop is needed to keep the compressor happy at 50Hz. Maybe the control unit handles this maybe not.
I work with international data centers that are 240vac quite often.
We have three wires for 240 volt Hot-Neutral-Hot plus ground; H to H is 240, either H to N is 120v (which you don't have now)

The outlets can be converted easily as you noted because in a 240v country you use no "neutral" third wire like we do in North America. The existing two wires plus ground can be used for a 240v outlet.

As noted by @dtfeld the water heater can be converted to 240v simply by getting the correct 240v element locally. 50Hz will not matter it's just a big resister.

The vacuum I would just get a similar sized head from a 240v shop vac and swap it out.

The fridge depends on the make/model again. If it is really a 12v compressor. And just front ended with a 120v-12v power supply you could just swap out that supply with a 240v to 12v.


Now in item C) you say 240v from the generator, but D) "using a 120v to 240v inverter".
That's a bit odd all you normally need is a step up "transformer", no electronics required, but it may be at 60Hz if the generator is an NA model.
240v at 50Hz? Pictures can always help.

Now if your generator is also a NA unit it may have the option to change the terminals for true 240v instead of 120v we would need the make and model to look it up. It may even be able to put out both 240 and 120 as in NA but likely at 60hz. The frequency is controlled by speed of the engine, the governor could be adjusted to lower the rpm slightly. The problem that may arise there is if it has electronic voltage regulator with frequency monitor it needs be set to 50Hz or it will think the 50hz is caused by an engine under speed/overload. Replacement 50hz regulators are often available.

Assuming a 240v to 120v step down transformer, 50hz vs 60Hz: motor loads like A/C and refrigerator. Check the name plate ratings they may even be built for both. Motors will run a bit slower, use a bit more amps, and run hotter but may be alright you would need to monitor them carefully at least initially. An IR temp gun would be essential.

Things like a microwave would likely be best to just get a 240v locally.
Thanks for the replies . I may have misled a little, the generator currently outputs 110v at 60hz. It can be changed to 240 as you say , but my intention for now is to leave as many 110 devices in place as possible, and just use a transformer to run them when on 240v shore power . So the hertz issue is the main one. A full 240v conversion is something I’ll look at at a later date.
 
OEM I think your boat was a two 30 AMP 120V 60hz shorepower supplies. There was no requirement for the US split phase 240 volt even though typically when connected we get that split phase.

So let's say everything on your boat is US 120V 60hz single phase. It is divided between two 120V 60hz shorepower sources. Those two shorepower supplies continue throughout the boat separately on both the hot conductors as well as the common conductors. In the US this is essential for Ground Fault Safety.

Wiring - All of the boat's wiring will be good to go as you are doubling the voltage but the amperage stays the same - in fact, now the wiring is oversized so to speak.

As your generator (probably a Westerbeke) is 120V 60hz the transfer switch disconnects the shorepower hot and neutral legs (all four) and connects the two independent systems on the boat to the generator's single 120V 60hz output.

There is a bit of an efficiency loss between 60hz and 50hz but essentially going from 120V to 240V the current can be doubled. This means that you can combine both of the existing 120V 30A shorepower lines to a single 240V 30A single phase supply. I would abandon / remove one of the shorepower receptacles and tie those wires into the other. Now the entire boat is 240V 50hz 30A.

Now the generator - the Westerbeke can easily be re-terminated to 240V 50hz single phase. Your owner's manual provides the details on how to do this. Somewhere I read the RPM of the generator needs to be changed but maybe that is automatic with the wiring change but needs to be verified. The transfer switch remains the same.

Circuit Breakers - The boat's circuit breakers are protecting the wiring and devices downstream of the circuit breaker. Essentially, you are doubling the power capability on a circuit by raising the voltage to 240 but keeping the amperage the same. So, a 20amp circuit at 120V is capable managing 2400 Watts whereas a 20amp circuit at 240V is capable of managing 4800 Watts. The boat's wiring is good to go but you need to look at the end devices to see if the circuit breakers need to be reduced in trip current.

Now, you are down to the end items on the circuits. Each (HVAC, Water Heater, Range, Outlets, Chargers, Inverters, etc) all need to be evaluated and adjusted/changed/converted to the new 240V 50hz power. I'm not so sure your HVAC units can be converted if they are older as the compressors are 120V 60hz motors. The newer ones have moved to variable frequency and most likely adaptable to either voltage and either frequency - possibly with a switch of wires on the board.
 
Not to throw a fly into the ointment here but a few things.

If this was a 60hz boat then the only real way to covert this over is use a transformer where the power is coming into the boat. The AC compressors will burnup if ran at 50hz for very long. and why there is a transformer at one of the AC units. Things like the stove top (if digital) and the micro wave will not work at 50hz. It would be much easier in the long run to get a transformer and just fix the boat instead of the individual devices.

But since your part of the way through all of this it might behoove you to get another transformer for the 2nd AC unit. Then things like the microwave should just be replaced with 50hz appliances.

As mentioned the voltage thing seems to be covered and the original wiring is easily repurposed for the 240v requirement. Your year boat most likely has an 8 or 10K Westerbeke genset that is easily re-strapped for 240v/50hz. Please post exact year and model or a good pic and we can verify that. But that can be done by you it's only changing some brass straps on the transformer.
 
Not to throw a fly into the ointment here but a few things.

If this was a 60hz boat then the only real way to covert this over is use a transformer where the power is coming into the boat. The AC compressors will burnup if ran at 50hz for very long. and why there is a transformer at one of the AC units. Things like the stove top (if digital) and the micro wave will not work at 50hz. It would be much easier in the long run to get a transformer and just fix the boat instead of the individual devices.

But since your part of the way through all of this it might behoove you to get another transformer for the 2nd AC unit. Then things like the microwave should just be replaced with 50hz appliances.

As mentioned the voltage thing seems to be covered and the original wiring is easily repurposed for the 240v requirement. Your year boat most likely has an 8 or 10K Westerbeke genset that is easily re-strapped for 240v/50hz. Please post exact year and model or a good pic and we can verify that. But that can be done by you it's only changing some brass straps on the transformer.
A transformer cannot change frequency. Only a frequency converter can and they are expensive and big when needed to support any amperage at all.
 
A transformer cannot change frequency. Only a frequency converter can and they are expensive and big when needed to support any amperage at all.

Yes, sorry used wrong terminology, only one cup of coffee so far. But he seems to already have one installed, so perhaps get the same make/model. The best thing would have been an isolation transformer that incorporates this and keep the boat 60hz. I know Victron has smaller ones that will do this, I am waiting for them to come out with 12kva one that would also be the best fit here.
 
Yes, sorry used wrong terminology, only one cup of coffee so far. But he seems to already have one installed, so perhaps get the same make/model. The best thing would have been an isolation transformer that incorporates this and keep the boat 60hz. I know Victron has smaller ones that will do this, I am waiting for them to come out with 12kva one that would also be the best fit here.
Large yachts have to convert when traveling internationally. There are companies like ANG that make the converters and they make them in smaller versions like 15KVA. The issue is all of the devices that plug into outlets that they want to use are 240V 50HZ - so it's a mixed bag on the boat. They could install a converter for the boat's loads but it gets really complicated splitting up outlets from fixed systems and having a generator that can be only one or the other....
 
Large yachts have to convert when traveling internationally. There are companies like ANG that make the converters and they make them in smaller versions like 15KVA. The issue is all of the devices that plug into outlets that they want to use are 240V 50HZ - so it's a mixed bag on the boat. They could install a converter for the boat's loads but it gets really complicated splitting up outlets from fixed systems and having a generator that can be only one or the other....

That is a good point and one I hope I would have thought of on my 2nd cup of coffee.

But to your point, the external peripherals that are looking for 50hz would be an issue and probably why there is a converter for one of the AC units already. Costly to go with either option of converter or new AC unit.
 
That is a good point and one I hope I would have thought of on my 2nd cup of coffee.

But to your point, the external peripherals that are looking for 50hz would be an issue and probably why there is a converter for one of the AC units already. Costly to go with either option of converter or new AC unit.
So, I would have left the entire boat 60hz and installed a converter to convert the shorepower 240V 50hz to 120V 60hz. Then for the outlets get those small 120V 60hz to 240V 50hz plug in converters like we need to travel internationally for our plug-in devices.
The only issue becomes that when something fails on the boat (like a Cruiseair HVAC unit) they need to order from the US.
 
the amount of detail provided by the various contributors here is superb, as is usually the case clubsearay forums is full of really helpful people. Many thanks.

yes my westerbeke is a BTD8, the original one installed in 1996. It is changeable to 240v and this does involve it running at a different speed. But I probably am not going that route

I think I am looking for the simplest approach even if it's only a small increment of improvement with compromises.

When I am on the generator everything is as it was in 1996 except the visible outlets in the cabins which are powered from the generator by a step up transformer. So rather than interrupt that setup which works fine, I am more inclined to improve the hybrid system I have for shore power but not totally replace everything.

As said, my current shore power setup is merely 240v into all the visible power outlets using the port receptacle which has been changed to 240v, but only for those outlets. The electrician would not have connected the port appliance circuits (vacuum, microwave etc) to that 240v supply as there is no step down transformer. In fact I am probably never going to flick the 110v shore power switch on the panel for the port circuit as I can't get my head around what might happen if he didn't fully isolate it.

Here's a pic of my control panel, it might illustrate better. The added switch in the middle switches between three options
a) Shore power 240v to outlets
b) No shore power no generator to outlets
c) Generator to transformer to outlets.

Also a pic of the receptacles where you can see the port receptacle replaced by 240v but cruelly sacrificing shore power to port circuit appliances

I think the smallest improvement, would be to send 240v thru a transformer to 110v into the starboard receptacle, at least giving me charging (would charging work at 50hz?), and the fridge should be ok as it's 12v Tundra with transformer (Vitrifigo same deal but different name). But the hertz issue arises with A/C , as said in above responses, the old cruisair compressor will probably spit the dummy not to mention the pump running slower so less water feed. So no A/C, no stove probably, and I would still not have Port appliances on shore power. So I don't get much for the effort but it's a start

I might talk more about the water heater (i have another idea) but I'm cognisant of the effort taken with all the help already provided which I really appreciate
 

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c) Generator to transformer to outlets.

That is a scary statement, one which I hope has a breaker somewhere in there.

As for the generator, dropping the rpm to 1500 is quite easy. And removing a transformer is just as easy.

I my opinion you should fix the boat right for your area. Or what @ttmott suggested and leave the boat @60hz and only convert the incoming power to what the boat wants.

No offense but your going at this the wrong way and you will only end up with a very big dangerous kloogy mess.
 
That is a scary statement, one which I hope has a breaker somewhere in there.

As for the generator, dropping the rpm to 1500 is quite easy. And removing a transformer is just as easy.

I my opinion you should fix the boat right for your area. Or what @ttmott suggested and leave the boat @60hz and only convert the incoming power to what the boat wants.

No offense but your going at this the wrong way and you will only end up with a very big dangerous kloogy mess.
Thanks Skybolt, yes there is a breaker, the system as it stands was professionally done. Any changes would also be done by a qualified mar(ne electrician as my insurance would not stand up to diy in this space.

yes, I would like to leave all the 60hz stuff really, but I can’t convert 50hz to 60hz from shore power without according to the trail seriously expensive kit. I think at the end of the day that’s the key blocker in a nutshell , I can see why the electrician did it the way he did. I have an abundance of 240v power from both shore power and genny (via the added transformer), so it’s not all doom and gloom. A full conversion means two new a/c units, new cooktop, microwave, water heater, etc. I reckon the PO who did it looked at the cost, the value of the boat and as we say in Australia, said Yeah, No.
 
I felt I had to update this thread as I started it and I had it wrong .

I’ve since tested the system and my understanding or probably more my assumptions, we’re in error. The installation for shore power is a single 240v feed through the port receptacle, which goes to a step down transformer (which I thought was a step up for the genny. ). When on shore power with my 240v sockets running nicely, I bravely flicked on the two standard 110v shore power switches , as I could see the little indicator lights flickering. This said to me that power was coming available to the 110v system. Maybe they only flicker because they are designed for 60hz. Anyway, all the 110v stuff works from shore power. The meters on the panel fired up it straight away registering 110v. So very happy.

I didn’t test the a/c because the compressors specifically say 50hz in the label, I might experiment with this one day and use a temperature monitor, as a post above implied I might burn the compressors up.

The thing I don’t understand is why my step down transformer hums when I draw lots of 240v current on an espresso machine, I’m wondering why that transformer is involved at all when the supply is 240 and the appliance is 240. I would have expected that 240v circuit to bypass the transformer. Maybe there’s another step up transformer somewhere that takes the 110v from the step down and turns it back into 240 for the sockets . That would tie in with the genny which must be using a step up that’s hidden away somewhere I haven’t found, ohh or maybe the genny has been set to 240v and it always goes thru the step down for 110v. So a few questions left for me to answer. I’ll be doing more discovery in due course, but at the end of the day, everything works and the hertz issue is not biting me, yet ! Woohoo
 

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