howdy friends! this time we will learn how to find out how many amps delivery to a transformer but before I want to leave three clear things that were left of the previous video there are three doubts the previous video is about how to identify the wires of a transformer up here I leave the link. Ok the first doubt that I view is that it is a central TAP so, the central TAP it's a center point that comes out of a winding for example we have a winding that from here to here, in the extremes we have 50 volts there is a center point that is taken out with a cable what makes here from here let's have 25 volts or from that same point to the other have 25 volts that central point we connect it to ground and so, when the amplifier is at stand by at the output of the amplifier have zero volts while if we did the amplifier with a simple power supply that is, with a winding directly from 50 we would have to the amplifier output Vcc 1/2 that is half the total voltage that would generate a Huum noise and we would have to place a decoupling capacitor so that we have 0 volts at the output it gets a bit complicated ... or the configuration is different and sometimes amplifiers are a bit more unstable when he has a simple source that's why symmetric source is used and the winding of the transformer must have a central TAP this topic can be seen a little better in our video how to make transformers that here I also leave the link the other doubt or annotation that I view was that when we watch the primary winding there was a point that looked like a TAP but it was not because when we measured there it also gave us the same voltage then, that point is the output of a fuse it turns out that there are many branded transformers that have a protection fuse then anyway they leave a pin of output in case the fuse burns we can connect directly and we do not have to change it although the ideal would be to disarm the transformer and change the fuse keeping the protection but if we do not want we simply omit it OK and the third annotation is that some tell me that to be able to measure a transformer you do not need the serie circuit that with the single multimeter can be done that's true it turns out that we we can place the multimeter on ohm scale and the winding that has the highest impedance that is the primary winding but that does not always work because if it's an elevator transformer for example what at the entrance we have in the primary 120V but we want you to deliver us at the exit 600 volts because it's a transformer for a tube amplifier of valves Well, it will not work or this other case may happen much more interesting we have for example a transformer 120 volts in its primary winding which has a 20 gauge but on the way out we have an additional winding apart from the main winding we have an additional 30 volt winding with a 32 gauge it turns out that the thinner wire is more impedance has then the case may come that we measure that secondary winding that is very thin and it turns out that there we have an impedance highest that the impedance we have in the primary winding and suddenly if we are beginners we connect there directly the public network and we burn the transformer at least we burn that winding so I do not think that it can always be done with only the multimeter I recommend you always use the series A series is very economical it's a very cheap circuit, it's a very simple circuit use it! OK now we'll see how to know how many amps a transformer has Construya Construya su videorockola to know how many amps a transformer delivers We can use two forms one, using instruments like this one a multimeter that we are going to use in amperes scale or a clamp meter and the other way would be using a calibrator let's see this form first. it is about to find out what gauge of wire has the secondary winding and then we look at our AWG table for example: here I have a transformer and this transformer It has three 18 gauge wires rolled up at the time to achieve a thicker gauge wire that's what they do in some companies since as that is rolled with machine it's a little more comfortable to wind thin wires and add them OK it turns out that here I have a little wire 18 gauge and I started to compare and yes It is the same thickness this one has 18 gauge wire Nevertheless If I had not I did not know what wire is I measure it with my calibrator and here I am realizing that you have 1.03 there you can see out there, yes 1.03 when looking at the AWG table that's an 18 gauge wire and there, in the equivalence of my table say what which supports 3.2 amperes so this transformer that we just saw here 3.2 by 3 = 9.6 amps that supports it turns out that by measuring it I view that he actually delivers 10 amps Well ok but then it means that it is not accurate? measure the caliber of the secondary winding? no, it's not exact. Why is not it accurate? It turns out that there are many AWG tables. for example: There are people who write me on the page and they tell me: hear, but is that your AWG table is wrong because mine says that 18 wire delivery 3.6 amps and you say that delivery 3.2 or vice versa OK what happens is that there are many qualities of wire and each AWG table it must be generated by the company what does that cable do in my case I buy the wire to a company called procables from here in my contry and they gave me the AWG table and with that is that I work. because when I buy the wires I buy there sometimes I buy recycled wire and I know that will not give me the same because I do not know the quality of that wire So what do you have to do if they are going to assemble transformers you ask him to the company where they buy the wire they ask for the AWG table of them and so you know exactly how many amps deliver their wires. of rest there is no way. OK there will always be a variation Ok So what do we do with that case? we have to know that there is a tolerance because for example this transformer I do not know who made the wire and see is of more quality than what I would have thought but the opposite also happens We will find less quality because more or less we give each other a range of how many amps our transformer has but they will not be exact. if we want more accuracy we have to measure with the instruments what are we going to see next Well, the first way we're going to see to measure the amps of a transformer It is the simplest it is not very accurate but it gives us an approach how many amps does the transformer have for this we need a diode bridge of good amperes watch out in this case I use one of 50 amperes and a 20 watt resistor it can be between 1 and 2 ohms all right what we do is the two transformer cables in this case this transformer has TAP then I use the TAP and one end they do not have to be the two extremes they can be only the two sides that is center and one side I connect them in the AC of the bridge the bridge as you can see here has a pin that has a different position than the others that is the pin + the positive output diagonal of this It will be the negative exit. and the two that remain they are the alternates so it's the inputs current we connect there our transformer Ok until there everything goes well Now: we need to measure the voltage of the transformer when we are measuring the amperes Ok It sounds confusing but what do I mean? here I have a multimeter that I place in alternating voltage and that multimeter I'm going to connect on these two pins on the same pins Transformer output do not worry if they do not see well here what we are doing if they are armed with a scrambled cables that down the video I will leave you a link with all the diagrams of connection of the different forms of measurement so do not worry let's look at is the content itself of what we are doing we already have this one here To measure the voltage OK? I'm going to put it ... let's put it here there it holds ready, OK Now we have our auto multimeter here but this is in amperes and obviously we passed the pin to amps the wire we had amps if we leave it here we go to the multimeter this goes here and here we are at 10 amps watch out If the transformer has more than 10 amps this does not work and for that there is the amperometric tip well then this one let's put it where do we put it on the screen let's put it there there, there you see on the screen Ok a little mess then here we go back to our bridge when we connect to the public network we see that the transformer has 26 volts here we have the resistance so see what I'm going to do this pin of the multimeter I'm going to connect in the negative I already have at this moment here the black tip of the multimeter with which we will measure amperes I have it ... there it is. on the negative pin and on the other side let's place the resistance to have how I make it look look what I do I put this tip at a terminal of resistor in a resistor terminal and with this one we're going to touch quickly the positive pin of the bridge Not very long, it has to be fast and read because this resistor gets hot since we are using it as cargo as if it were a burden on the transformer they will spend many amps for it then let's measure we see 7 amps 21 volts did they realize what happened? we have 26 volts but when I connect the voltage is lowered to 21 volts and we see 7 amps in the multimeter there we are realizing that the transformer is forcing it to deliver 7 amperes that does not deliver Really if we look at the cable that has the transformer it's a 17 gauge wire and the 17 gauge wire delivers 4 amps if we want really keep the voltage we can not demand this transformer more than 4 amperes that's what it gives but as we can see if we needed only 21 volts We could use up to 7 amps of he but yes, that transformer is going to overheat so we should always look not just the measurement we make with the multimeter but also the measurement What we do about the wire gauge it is important both if we really want to be shure how much the transformer delivers friends thinking in that problem that when we put a load too big to the transformer he gives us more amperes but the voltage drops I designed this card that has resistors to make different amounts of cargo There are 10 resistors in parallel you see these two on this side as if were in series, but no, everything is connected in parallel in the link that I leave bottom I'm going to leave you a very complete diagram of this circuit, to do it ere I did it on an aluminum plate so that the resistors dissipate their heat towards aluminum here is the diode bridge and every resistance has a switch with which we activate or deactivate. with this card we can measure a transformer and we are increasing the load to the point where the voltage begins to fall when the voltage drops we know that up there is that we can force the transformer and so we get a result how many amps delivery in a more precise way let's connect it then the first thing we do is to connect the transformer cables to the AC inputs from the diode bridge are the ones that are here Ok now the multimeter being on the scale of amps and with the cables in place to be able to measure up to 10 amperes we will connect it in these pins the black pin on the negative of the diode bridge and the red pin in this cable that we leave here which is the output of this circuit watch out! I come back and I remind you this circuit and all forms of connection They are in the link that I leave below the video. so everything will be very well explained now: our multimeter that is on alternate voltage scale we will connect it to the transformer pins on the two output cables of the transformer there is now that everything is connected correctly let's feed the circuit let's see. have 26 volts what the transformer delivers when it's empty that is, without load. let's turn on the first resistor It is a 10 ohms resistor so we're going to give you a 10 ohms load to the transformer. see what happened It dropped a little more than one volt, because we have: 26.3 and when turning on low to, 24.9 as 1.7 volts more or less fell and we have 2 amps of consumption the circuit gives us 2 amps with a very slight drop in the transformer well, up there it's very good. Ok I'm going to turn off a second the resistor heats up immediately this one is already hot then I will work with the one that next there it is, and I'm going to turn on another I took two, look, this had a fall... 23 volts and we have 3.9 amps up there, it seems to me what is really what this transformer delivers 4 amperes because he has a 17 gauge winding 4 amperes is fine and it only had a 2 or 3 volt drop that's the right thing if the transformer already falls more volts we are really forcing it for example: I'm going to learn 3 resistances one two, and three see what happened 5 amps but fell to 22 volts overly it should not be like that now I turn off I could light them all and if I set them all let's force it in an impressive way the transformer let's do it I'm turn on, it's and look what happened the transformer 13 amperes I'm going to turn off because it can damage my Multimeter since it has a tolerance up to 10 amps but if they could see I can connect again quickly Look! 13 amps we have there and it went down to 17 volts overly that is wrong we are already forcing the transformer too much then it does not work for that reason I tell you that one can not force a transformer and can not believe that because he put a super load already made the perfect measurement when one measures with a resistance of 1 ohm as usual will always have a measurement wrong because it is not checking the voltage so a good measurement of amperes it does with a voltmeter also that is, volts and amps must be measured at the same time and the fall of the transformer must not exceed 3 or 4 volts maximum maximum and from there to there those are false amps are not the amps that actually deliver that transformer and we will be forcing until we damage it Also if the voltage drops and we are talking about an amplifier it will sound smoother anyway Because is what the power of an amplifier depends on the voltage and if the voltage is down Well, we will not expect too much power I return and I remind you that the most precise diagram or with more order since here it is difficult show you all these cables find below on the page in the description there is a very complete article that they have to read to finish understanding this topic. this topic is not so simple I already leave all the details plus if they ask questions need I will be complementing that article so that the explanation is very complete ok friends and the last recommendation if they are going to measure transformers over 10 amps I recommend that you use a clamp meter like this one they lent it to me in a store called audio robótic in the center of my country in race 9a number 20-13 I send the greeting but it's not a sponsored video simply I'm giving thanks for lending me this clamo metter and can show it in the video it's no more. ok friends they already know hand up share that in that way they help us to continue with this work visit our web site construyasuvideorockola.com a hug for all and remember take care of your health!
