#96t Why does one need a Galvanic Isolator on a Boat | Sailing Sisu Leopard 45 Catamaran

in one of my previous episode episode that i was doing the under check for the boats um i mentioned that you need to check the galvanic isolator and this is the the one in questions the galvanic isolator so and people ask me what it was and i also say that i will make a video specifically on why do you need a galvanic isolator so for us to understand why we need a galvanic isolator um i need to maybe go back to a little bit about noble metals and least noble metals so noble metals another metal if we go back maybe even before that to an atom level atoms is consisting about neutrons which are electrons it's running around neutrons and protons which can make the the the core of the atom and then around it is spinning all the electrons and they've got very funny ways of spinning around it so we're not going to go into those kind of things but the the biggest thing is if you look and look at the shells and and of course these different shells because there's a figure a 18 is around one in lips one in and they all make all funny funny shapes and orbits around the core but let's just for for argument's sake say that we've got one ring on the outside so the electrons are spinning on that outside the outer shell if you want to call it like that if the if this atom has say five positions in outside shell and there's five electrons then this is a very very stable atom if there's one one electron missing um then it means there's four of them spinning around the outer shell and there's gap for one more so it's easier for this atom to gain an electron in that one once empty space than to lose four to actually make it completely that kind of like equilibrium it's not really equal agreement to say so it's easier to gain one to say all right we've got five instead of losing four the least noble ones is again the other opposite side so it is there's one electron there's supposed to be five but there's only one electron spinning on the outer shell and this electron is easier for this atom to lose this electron than to try and gain four to make five so the noble ones have just one empty space and it will gain the electron while the least noble ones will have one electron and will easily give it away rather than to take four new ones and this is what's happening with with galvanic voltages and galvanic currents so galvanic currents is the the least noble one will leave will give his um electron to the noble one to actually receive the electron in that one space so the electrons will flow from the least to the most noble metal and this is what's happening between the different metals if we look at this list of the currents that's basically the like the electron load if you want to call it like that the potential for it to lose its electrons and potential to actually get electrons so if you look at the just the electrical current that is possible in you will see the top of the list is magnesium or magnesium so that one will sacrifice its electron a lot faster that the ones that below it and if you look right at the bottom on the second page you will see there is plutonium and plutonium is a noble metal and that metal will rather take a electron than to try and give electron so if you look at this list it is actually in that priority the top ones will sacrifice themselves for the ones below them now if you look at the voltages we each one of these metals also have a voltage and a voltage is measured there's a neutral way of measure the voltage for each one and this is the galvanic voltage that we're talking about so again the the least double ones on top of this list will have a negative voltage while the platinum has kind of like almost not really high positive voltage but there's a voltage and a current will flow between this from the high one from the negative to the positive so the current will flow from the negative to the positive and it will flow again then from the magnesium to the platinum if you look at that so it will jump any metal that is above another metal will there will be a current flowing from the top metal to the bottom or the one below or all the metals below it and this is why we have this so this is a magnesium alloy for the sail drive so you can look at that this is a sail drive um anode and we call them anodes because these guys were then easily released its new electrons instead that the propeller for example will lose the electrons and you will actually basically lose your propeller because this one is sacrificing electrons and the more electrons it is sacrificing the more material and deteriorating the this metal will start deteriorating so this is the reason why we have these things so again why do we have then a galvanic isolator if we have already nice sacrificial anodes that will actually give itself for the more noble metals the thing is if you are going to be connected in a marina to shore power then this green wire here is going to be connected between your boat shore power and every other boat inside the marina if it's connected to all the boats they call it kind of like a galvanic cell or a big big ass battery and every piece of metal that is in the marina in the sea water in the electrolyte will then start acting as a big ass battery and you need to decide whether your boat is going to be a cathode or an anode or neutral if your boat has a least noble metal like the anodes or sacrificial anodes or a brass propeller and other guy as a stainless steel propeller then the stainless steel because it's an ir it is more noble so it's lower on the list and your propellers is brass propellers or something like that and it's higher on the list or your galvanic insulators or the sacrificial magnesium alloy that you're going to use that is going to be then the least noble metal so the guy with the stainless steel propeller next to you will become the cathode and you will become the anode and all of your metals will go into the water because it releases the electrons towards the stainless steel propeller so you need to protect yourself against that so that you not become part of this battery if you part of the battery will either be a cathode or an anode and if there's any steel boats around you that have stainless steel in the water then you will become the anode and this is why we have a thing like this because this thing is creating a big gap between your earth and the marina earth the thing is if you look at the this this green wire this is earth and you need earth every boat needs earth if you have 220 volts if you have 220 volts then you need to have this green wire wired in otherwise all of these little switches here will not work this is no circuit breakers and things like that so you need a circuit breaker to actually detect that this earth leakage and you also need the earth leakage and if if that has been detected then it will trap and you will be saved from electrical shock you will get a shock but you will not easily die if this thing is in place so this is why each boat need to have a green wire now if you look here there's a gap in between so if this device doesn't work anymore for example if if the diode is breaking or something like that is breaking then there will be this big gap between the shore power earth and your boats earth which again brings you into a lot of trouble so you need to make sure that your your galvanic isolator is adhering to a lot of safety boards and after certifications for that and so on because if this one break you want this earth still to be working in a case of the pro safe i think they're using also a capacitor because the ac current is moving up and down up and down and because it is alternating it will also the the the capacitor the the plates will actually follow each other so this the current will still go through and you will still be protected but this one is working with two diodes and also capacitor so two diodes in series going one direction and two diodes in series going the other direction so that the current can flow in both directions so why do you use a a diode a diode is for it to start flowing is 0.7 volts then the current starts flowing so at 220 volt this one is perfectly working but the galvanic volts that mean the table that we just checked so the galvanic vaults according to this table here you will see that again you will see that again magnesium is a very negative voltage while platinum is almost it is definitely a positive voltage but it is just just over zero volt so these these guys here is a very negative voltage and the voltage will then again the current will flow from them to to the positive so they're sacrificing itself according to this table everything on top is more negative the one below it and that is the the reason why the the electrons will flow so what they do is they put inside this one they put a circuit to have two um diodes in series which means is point 0.07 plus 0.07 and that will then make up 1.4 volt which most of the time all the galvanic currents or voltages will not go higher than 1.4 volt on a boat and this is why this is making it then safe how do we test a galvanic isolator now i know this one has a capacitor in because it has a capacitor it has a few tricks up its sleeve but normally what we need to do is we need to make sure that the shore power first is off so we need to make sure the shore power is off so ensure your shore power is off and as you can see there's no shore power here so pull it out and we are at anchor so the chances of us having shore power is pretty slim but we do have an inverter so we need to make sure that the inverter is switched off and the way that we do it is we just come here and we switch that one off that's a short power there and this one is the transfer so it is now off the first thing that you need to do is make sure that your ic power is disconnected from the shore so unplug your shore cable and you you can even test whether there is any any voltage so i'm going to put mine on 400 because it's 220 um so i'm just going to i'm on anchor but you can you can also do it you put it here on uh 300 volts volt ic and then now i can measure between this point over here and that point and it is zero i can go to my neutral and i can also see it is zero so there is no live voltage on sisu and it's very good okay so we off shore power then i'm going to put it at the at the list ohmmeter we're going to disconnect this one we're going to disconnect this one from and take it completely out of the circuit and one of the requirements is is that it should be a ring and not a friction thing so now this one is out of the circuit i'm going to switch my my voltmeter or my multimeter to the lowest voltage to the lowest resistance i switch it to the lowest resistance and now i need to i need to check this and you will see there's a brief moment when there is something and it just jumps up very high so this means we've got a galvanic isolator device on this boat if it was not and it was it will go down to zero or very close to zero if you measure between this say uh this green wire over here on this side here and you measure your your shore power wire and there's there's no resistance then of course there's a problem but if you measure and it is like this and like that then it will go to zero the moment it goes to zero you know that you are or very close to zero then you know yes your there is no galvanic device on the boat okay since we do have one we know now we have one we can actually see it so i'm going to put this device now on the it is called the ohm testing so you can see it's a little diode and it has a little peep and if there's a short circuit it will make a noise okay so let's see the reading over there i'm going to it is now set for if you look here it is set for diode so it makes the noise if it's a short circuit and if i press it over the two you will see it it has already a reading and it goes to zero and that means there's a capacitor inside there we can reset the capacitor so we reset it by short circuiting these two things and then now it will briefly start and it will count up and it's testing the other diode so the diode is is that is basically millivolts that you see there so it's 300 millivolts so it's 0.4 volts already and a diode normally start conducting at 0.7 because we have two diodes in here it will start conducting at 1.4 if it doesn't at basically 1400 if it doesn't start conducting at 1 400 then and it climbs to say 1 500 1 600 you need to release like let it go otherwise it will it will maybe damage it so let's see how far this one is going one three uh one three three one three three seven so it goes all the way to 1.337 which is very close to two diodes in series that is 1.34 volts at this moment so it's one thousand three hundred 340 millivolts and this is how many 1.3 volts okay so i can now exchange remember the black was on top and the rate was at the bottom so if i exchange now the two it will count down down down or what i can do is i can just short it so the capacitor is now shorted so we will start again from zero and it will count up up up and hopefully it will stop at one point four let us see if it's going to stop if it doesn't stop it means the diode is not working if it goes only to if it goes less than 1.4 like yeah say for example 0.8 then it means the other one of the diodes is open and your device is not working if it doesn't go at all it means both of them is open and then you have a problem so um it has to be around 1.4 if there's two diodes in your device there we go one three three is the same as the other direction so it means both the diodes in both the directions is working properly and this is how you test it so in short this device is making sure that the earth is still still connected so that if i do have working on 220 volt then we are good if we don't work um if it does break it doesn't make a big gap in the wire so that you lose the earth capability inside your boat so you must have that fail safe built into your galvanic isolator that if this device breaks that you still have earth on the boat otherwise that becomes dangerously dangerously unsafe but the main thing why it's called the galvanic isolator is there's two diodes inside so from there is one dire two diet and then it reaches then it reverses as well one direct from there to there to to there so there's two diodes going from there to there and two rays going from here to here and those two diodes combined as you now just saw mine is 1.337 gives you that voltages that actually make sure that the galvanic voltage difference between any metals on this boat and the water it will not start flowing so my boat will not sacrifice any of our metals like the propeller or our zinc all the magnesium sacrificial anodes it will not sacrifice any metal because of another boat which has a problem that is a big thing if you want to keep your nice because you can have you can protect all of your boats stuff but if the neighbor next door from you has a problem remember the old big battery thing we are in one big battery then all our points that's going into the in the water is either anode or a cathode and you would rather to be neutral in this whole whole saga of the battery because this is what the galvanic isolator is trying to do to you is making your boat completely neutral if your boat doesn't have it you become an adult or a catholic so if you have these things you become an anode and you sacrifice this if you have a brass propeller and a guy next door have a stainless steel propeller you will sacrifice your your brass before he will lose his stainless steel propeller so that's that's the reason why we have a galvanic isolator stray currents don't don't get confused with straight currents this will not protect us against straight currents because a strike current is basically a short on any of these ones here and that short will be much higher than 1.4 volt so your anodes will definitely go very fast strike currents can be either onshore while you at shore so you can have a short one one of your two 20 volt systems or you can have two different different batteries in a two starter batteries and the two starter batteries might not have a very good negative wire connecting the two battery negatives and because the maybe it's a thin negative wire and because it's a negative wire the batteries is is struggling to to equalize and then they will use the one propeller and other propeller to try and get the equalization uh running between the batteries that means one of your propellers is becoming an anode and that is a problem so that is a stray current and not a galvanic isolate galvanic current so galvanic current is just between dissimilar metals it is a current between two dissimilar metals there's similar metals between two dissimilar metals the similar metal

Channel: Sailing Sisu

Views: 5,953

Keywords: Sailing Sisu, leopard 45 catamaran, leopard catamarans, catamaran for sale, catamaran cruising, sailing catamaran, catamaran, catamaran sailing, sailing, sailing around the world, sail around the world, blue water cruising, circumnavigate, yacht, cruising, boat life, vlog, cruise, living on a yacht, sailing video, sailing life, sailing yacht, solar powered, wicked salty, impi, delos, the wynns, galvanic corrosion, galvanic isolation, galvanic cell, galvanic isolator marine

Id: Ai8fRiaurKU

Length: 24min 15sec (1455 seconds)

Published: Fri Aug 14 2020