Why Do Capacitors Fail? (It’s not why you think)

[Music] so depending on the part of the country that you live in you may have a major problem with capacitor failure or not and we noticed that in hotter states states with higher temperatures that we see much higher rates of run capacitor failure now the first thing about this video if you don't hear anything else I want you to hear that this is about run capacitors so capacitors that stay in the circuit all the time and for the compressor condenser fan motor and the blower motor and run capacitor doesn't have a relay in it like a start capacitor and so it doesn't it's not affected by turning it on and off it doesn't have to come out of the circuit at a certain point like a start capacitor so a lot of the confusion that I see when it comes to things that technicians think of as causes for failure they those are causes for failure for start capacitors but not for run capacitors so the reason for this video is when you have something that fails as much as run capacitors do especially in certain parts of the country people want to come up with theories about why they fail and it's important that we know what can cause them to fail so that way we can do what we can to prevent it and also so that we don't tell people the wrong thing we don't want to tell people that something causes something to fail if it in turn if it actually doesn't cause it to fail so in this video we explore some of the different common theories out there and so some of the common theories are that if your motor is drawing high amperage that will cause the capacitor to fail sooner so that there's something that goes on inside the motor itself that causes the capacitor to fail many have said that they notice that a system that's low on charge seems to have weak capacitors or a system with the dirty condenser coil seems to have more commonly failed capacitors some people have said including my own brother have said that they've noticed that it seems like capacitors fail more often when the voltage is low the applied voltage coming in is low and so I want to explore this and to start with before we go any further you have to have a basic understanding of what a capacitor is and the best way that I can kind of get you to imagine it is think of a capacitor a run capacitor like a storage tank or like a pressure tank so if you're used to pressure tanks and say well pumped for example you understand that it pressurizes that pressure tank and the amount of water that can be stored in that pressure tank is contingent on the incoming pressure so you can't have more pressure on the pressure tank than the incoming pressure coming in and that's how the Pasteur works a capacitor can store the electrons that are forced into it but at some point it can't store anymore and that's dictated by the amount of pressure which is why the amperage of a capacitor is dictated by the voltage applied to it the capacitance of the capacitor and the frequency and so first off the bat if you're in the u.s. frequencies pretty much 60 Hertz now could there be some cases you know we see capacitors installed in variable frequency drives and whatever where you have some various frequencies and so could that affect the capacitor absolutely it could but for most of what we do it's pegged at 60 Hertz and in Europe and other places it's at 50 Hertz so if you're hurt stays the same your frequency stays the same and your capacitor has a certain capacitance rating then the amount of electrons that can go in and out of that capacitor are now just fluctuate based on the voltage if you think of it like that pressure tank for the pump you may can receive electrons and it can store them and then it can release them that's that's essentially how it works and as that phase changes it's constantly storing and releasing 60 times per second so we're gonna explore some of these things and see if we can test and prove exactly how this works give you a better sense of what can actually cause the capacitor to fail [Music] the question is what are the things that can cause a capacitor to fail and there's a common belief in the field that there's something that the compressor can do or the system can do to cause the capacitor to fail but the more that I research it the more we learn that the capacitor has a fixed amount of current that can go in and out of it and so I want to do some demonstrations here to kind of show what I'm talking about first measure the voltage and then the amperage off of this test Oh 770 - 3 291 volts our start winding we've got 4.2 okay so he's gotta have that as our baseline four point two amps 291 volts that we've got 212 213 volts something like that [Music] you [Music] [Applause] this is just an image of a typical capacitor and then over here we have a kind of an old-school wiring diagram and so what we're going to be focusing on is the capacitor that's this part here and then this is a dual cap and a dual cap one side would be the C side and so the C side would be the side that connects over to the run side of the circuit so one of the legs of power the same side of the leg a power that connects to the runs out of the circuit is the one that goes to the C terminal and then our Herms ID is the side that goes over to the start winding so let's establish some things here in order for you to have a potential difference a difference of voltage between C and s on the start winding C here we have to have a movement of electrons in and out of this capacitor so a couple quick rules here capacitor electrons cannot pass through a capacitor they don't go through one side to the other they can't there's no connection between the C and Herm sides inside that capacitor there's just an attraction across the plates so they gather on one side so a positive charge gathers on one side and negative charge on the other and that it as the phase switches of the incoming alternating current on our lines then it switches back and so what this capacitor does it adds in a phase shift so it adds in a 90 degree phase shift which helps correct for the phase shift that occurs in the inductance of the motor and motor is an inductive load and so there's this thing called inductive reactance we won't go into that but it's correcting for you know it's creating a unitary power factor and it's helping the motor run in the right direction with torque as we'll keep it really simple when you have a run capacitor that capacitor has a capacitance rating so this capacitor here we'll say it's a 45 by 5 but in this case of the compressor it has 45 micro farad's micro farad's describes how many electrons can be stored and discharged in and out of that capacitor so the only electrons that can go through this start winding are ones that can store and the other side and then back again now that can change with frequency but as you know the typical compressor capacitor your frequency doesn't change and since the frequency is stays at 60 Hertz then the amount of current that can go in and out of this capacitor are completely dictated by the capacitor itself capacitors have voltage ratings on them we've talked about that and so if the voltage goes higher than what the capacitor is rated for then the capacitor can fail because the electrons can actually bridge either across the two plates or it could bridge to ground and that's a problem another thing we know is that the changes in ambient temperature can also affect the life of the capacitor alright so we've got a 90 degree ambient condition so it's good and good and warm outside I'm gonna use this K type B probe and attach it to the capacitor and see what we're reading with it running normally I've got the bead probe attached to the K type K type thermocouple attached and it's running ninety one point six degrees right now so just barely over ambient temperature she's good and running for quite a while now I set the temperature downs that will keep running I'm feeling I have it connected with alligator clips measuring the wattage and the power factor and it's showing that I'm at unity power factor which means that capacitance is doing its job to overcome the inductance that's a whole other kind of conversation but just want to make sure that the capacitor is indeed functioning properly and definitely is sure everything's everything sighs properly so now let's see if we can get the temperature to go up on this capacitor by short cycling the equipment all right here we go don't try this at home not good for the unit I'm gonna short cycle it like crazy all right so an interesting kind of unintended consequence happened here that compressors running backwards that the sounds of it and we get a backwards running compressor now pre-set enough yes oh this is a pretty new unit and it was only installed three months ago and it's got a Copeland scroll in it so it's a good good compressor but yeah we definitely saw that short cycling caused it to run backwards which you know when that happens in real life that's not a good thing it's not gonna run properly we were only drawing 3.6 amps on common wire whereas before we were drawing over 7 and you could hear that sound it was just not definitely not right now we're back running normally again can see so far no so first off you can see on this graph it shows you that the higher the voltage is anything above the rated voltage it very quickly decreases the life of the capacitor so if you have a high voltage surge from the Power Company or you have a lightning strike or anything like that in the area then that's gonna greatly decrease the life of the capacitor you're gonna get bridging across those plates and it could very easily cause it to fail and then if you look at this next image here the higher the temperature is the shorter the life of the capacitor is going to be the lower the temperature is the longer the life of the capacitor is going to be the ambient temperature around what you're not gonna see is an amperage rating well why is that well because amperage current is dictated by the number of electrons moving through a conductor and that number through the start winding is completely dictated by the capacitance now some of you may say hey I know for a fact that I see high ink I see high current on a compressor when it starts up so I think a locked compressor can cause a capacitor to fail I think high current can cause the capacitor to fail so you're reading on the common lead the lead coming from the common terminal a common isn't a winding it's just a point in between run and start so when you read current uncommon what are you reading you're reading run and you're reading start you're reading their current on both of those lines right if you were to just measure on the start winding though do it sometime if your meter has an inrush feature on it put it in in rush mode and measure your start amps and you'll notice that your start amps with a normal system that only has a running capacitor and not starting capacitor or starting capacitors it will not draw high current you will notice that when you have a start capacitor in place and a potential relay that initially when it starts up you will have high current on the start winding that's expected because the start capacitor only stays in the circuit and the start winding for the first couple milliseconds until that compressor gets up to 80 percent of its total speed so that's going to happen very very quickly I'm in the first fractions of a second if you have a meter that can do this that can read that in rush amps then you will see a higher start reading when it starts up and that's only because you have the additional electron capacity of these capacitors in the circuit if you don't have this whole you know set up in here you don't have a start capacitor with a potential relay and you only have a run capacitor then your amperage on start and run are going to be the same because your amperes are dictated I the number of electrons that that run capacitor can hold experiment sometimes put in a smaller run capacitor smaller than it's rated for and measure your start winding amps then put in a larger run capacitor and then measure your start winding amps you'll notice that when you put in a larger capacitor you have more amperage when you put in a smaller capacitor you have lower amperage so the amperage of your start winding are completely dictated by the voltage and by the capacitance now some people will point out well your motor does add inductive reactance when you measure in between these two points between start and common you see a much higher voltage than the applied line voltage and that's because of the back EMF that occurs within the start winding its back electromotive force your motor actually acts like a generator as well and actually generates a higher voltage but again the highest voltage that your motor is going to generate is when it's up to full speed that's not going to be during starting and much of the things that are attributed to failures in a capacitor or when people say well when the motor has a hard time starting or when the systems short cycling then that causes your running capacitor to fail now high ambient temperatures can cause you're running capacitor fails so if the unit's getting hot you have a failed condensing fan motor or something like that then that can cause it to fail prematurely and then also high voltage conditions can cause it to fail prematurely or if you had some you know higher frequency or something that could cause it that would be extremely abnormal but with all things being usual the only things that can cause a run capacitor to fail are high voltage high current or a run capacitor that is poorly designed poorly executed poorly manufactured or it's just at the end of its life I mean so everything has a life expectancy over time but that's the reason why I'm a big fan of the mrad capacitors because we've seen that they form more to spec than some of the other ones that we've seen we see that they're they're very well made faster so that's it what can cause a a run capacitor to fail well the only thing in causes to fail is higher voltage which also could lead to higher if you have higher voltage than you will have higher amperage on your start winding higher than designed voltage or higher than design temperature or just higher ambient temperatures over a longer period of time will also cause failure alright so let's try it again I'm going to try to give it a little more between my cords I came [Music] now we're going to test in rush amps on the start winding and show the difference between in rush and full load amps on the start winding verses the runway alright so this is our regular running amps our start winding coming from our capacitors so that's connected to her connected to her am rad turbo 200 so it's connected to 45 micro farad's I'm going to go ahead and shut it off and then I'm gonna put it on in Russia there we go in rushing amps so now let's see what we get on startup let's try it again just to see if there was something weird going on there amps it's currently off in rush there you go in rush amps let's see what we get nothing alright now we're gonna try it again on the common of the compressor actually let's do it let's do it on run just so that we're because what I'm wanting to show you is that it's run that sees that in rash not start no that's it in rush so this is on the run winding of the compressor here we go alright so there we had an inrush of 60 so no inrush on started all didn't even log it and that's because on the start winding the capacitor inhibits the amount of current that can flow through the amount of current they can go through the start winding it's completely dictated by that capacitor because electrons aren't allowed to move actually through the capacitor they can only go in and out of the capacitor so the capacitance dictates that and see here still at 92 degrees even after all this monkeying around and short cycling that I'm doing what you see uncommon is start bus run right so you get that so let's now measure the inrush amps on common to help additionally prove that the all of the inrush is on run and not on the start winding in rush all right now well would you look at that common and run show the same in Rush and start doesn't show an inrush at all so if we have a locked compressor that capacitors not gonna see that increase in amperage that increase in amperage is going to be seen on the run not on the start in some cases you're gonna notice that your run wire is connected not back to the contactor but actually back to the capacitor so in some cases your run winding isn't going to go to the contactor it's going to go to the capacitor and then the capacitor acts as the junction point in that case you will get additional heat because it's using the capacitor as a connection point to make connection for run in this application here your run winding goes right back to the compressor there's right from the contactor to thing compressors so any heat that's built up is gonna be built up through here it's not gonna go to the capacitor at all if you look here we've been messing around with this thing for a while now and our temperature of our capacitor is not increasing when we talk about amperage we're always talking about amperage on common that's where we measure it and so the assumption that a lot of technicians have is that when you see an increase in amperage on common that that's going to equal an increase of am and amperage on start but the thing that they miss is that the amperage on start is dictated by the capacitance of the capacitor and the incoming voltage higher voltage is going to result in higher amperage on the capacitor and the capacitance of the capacitor is going to result in higher amperage on the start winding of the capacitor some Tech's get confused they combine together the concept of a start capacitor which has very high capacitance and thus will have a lot of amperage on it but it's supposed to be taken out for a short time with a run capacitor that is always in the circuit or on capacitor never comes out of the circuit all right so this may be another way that's kind of helpful to you to understand what I'm talking about because the thing that techs have a hard time getting their head around is the fact that the capacitor is what dictates the amperage on the start winding this doesn't seem right because we just imagined that somehow electrons are coming through one side getting boosted up and then go into the compressor like that's how a lot of texts imagine this and you got to get your head around the fact that that's not how it works at all in order to help this make sense what's actually happening is you have a current that's gonna travel through here and then go to start is this common and then it's going to go through to start store and then release back the same direction that it came from and that's what creates that phase shift and then we also have a higher voltage applied on it because of the back EMF from the motor and so in this example this is how to test to run capacitor under load it's on the resources tab of HVAC our school comm and so here you can see we have an applied voltage across the capacitor of 292 point nine from here to here and then we have a compressor start wire seven point eight this is actually a real unit I got these readings off of and so if we want to find the capacitance we can use these live readings right well how would that work if this amperage wasn't completely dictated by the capacitor and the capacitor size and the voltage you understand that it wouldn't work the amperage the voltage equal the capacitance and that's how we do it so we take the amperage 7.8 amps we multiply it times a constant 26:52 some people use 26:53 or 2650 makes the very little difference 7.8 times 26 52 divided by the applied voltage equals the capacitance you'll notice it doesn't know we're on here are you taking the amperage of the compressor other than the start wire you're not taking the run wire amperage you're not taking the common wire amperage you're not measuring the applied voltage earning that stuff you're literally just saying what is the voltage applied to the capacitor and once you know the voltage applied to the capacitor and the amperage then you can determine the micro farad's of that capacitor under load which indicates to you that it's the capacitance and the voltage that dictates the amperage that the compressor is going to draw on the start winding the only way that you could have higher amperage on this start winding is if you had higher voltage or higher capacitance and the voltage increases above the applied line voltage based on the back EMF that comes from the motor which only happens when the motor starts to speed up so that tells you that if anything you're only have a run capacitor in the circuit that if anything your amperage will be lower on your start winding when it starts then once it starts running because that back EMF only comes up this voltage only increases once this motor gets up to speed all right so let's do another quick demonstration so a lot of technicians you know that this is a run capacitor right or something real quick there's no relay in this this is constantly in the circuit when it's when it has voltage applied to it when it has potential applied to it a lot of confusion between a start capacitor which has a potential relay that takes it out of the circuit and a run capacitor which constantly stays in series with the start winding of a motor okay so this stays in the circuit all the time let me ask you a question if I take this plug and I plug this into 120 volt source and I connect it to this capacitor what's gonna happen well some guys think I've asked a few and some think it'll do nothing some think that it will be a direct short and so let's show exactly what happens when get in that way so this is a turbot tuber 200 mini I am and so it has a five two point five and a 7.5 so we're gonna go for the 7.5 we're gonna go for the gussto here 7.5 is the brown then we're gonna connect this to the center I'm gonna put on my gloves my glasses so that way here it remember what you think is going to happen first and then I'll show you what does actually happen and rather than showing you the voltage I'm just going to prove it to you by showing you the amperage on this wire look at there things drawn half an amp drawn half an amp how's it drawn half an amp is it actually creating any heat is it doing any work the answer is no it's not that is all reactive power which means that it's creating and out of phase so it's storing and discharging it's taking from where it came from and then putting it right back again that's what a capacitor does if you imagine almost like a balloon fills up and then discharges fills up in the discharges that's sort of what it's like but there's no actual connection in between these terminals these two terminals aren't shorted together you have a plate and then you have a magnetic field or an electrical field that builds up on either side of the plates that attracts and then repels the electrons in and out so this thing is like a little electron balloon that's just constantly filling up in discharging filling up and discharging there's a differential charge across those two terminals what will happen if I apply a higher voltage to this well first before we do anything else I want to show the temperature of this capacitor with it unplugged and then let it plugged in you can see we're unplugged here I'm going to go ahead and discharge the end of this because right now there's actually a charge here again this is the correct way to discharge your capacitor with the discharge which is 20,000 K 10 watt resistor that I have connected all right so thick I measure the temperature first let's take a look at the ambient right now when the ambient temperature actually went up quite a bit we're 95 degrees right now outside so we're gonna use this Cape type heat probe the actual temperature of that metal is below the outdoor ambient I just brought it in from outside so we'll let that stabilize for a second see what we see what we end up at now one thing to know about these is these are rated at over 150 degrees Fahrenheit so regular ambient conditions shouldn't cause these to fail but what we do know is is that increases on ambient conditions can cause them to fail earlier than they would otherwise so it's not like being in a hot temperature environment is going to make it fail but what will happen is if you're in a higher temperature ambient environment it's not going to last as long all right so we've stabilized here at 86 0.9 now let's go ahead and plug it in so we're gonna have some current passing in and out of it you actually now have electrons going in and out of this capacitor I can prove it there you go get electrons going in and out of this capacitor now the reason why these capacitors have metal shells they have oil inside of them and that oil helps keep them cool as as electrons are passing in and out because there is some heat generated as those as those electrons are moving in and out of a capacitor and because it's always in the circuit never comes out it doesn't have a relay that takes it out it needs to have something to keep it cool now over time it will slowly increase in temperature but with the oil fill and the amount of load that I'm applying on it right now it's not going to increase any significant amount of I've actually tested some of these before obviously it's going to increase in temperature because the outside is warmer than 87 so now let's go ahead and apply a higher voltage to it I have it connected to a disconnect section 208 so it's gonna be about 2 13 volts 1 13 volts right now our temperatures been rising because it's hot outside so right now it's 88 point seven degrees it's kind of hard to see what the glare but 80 89 degrees see if the temperature keeps increasing right so now we're gonna check the amperage you can see the amperage went up with the voltage so as the voltage goes up so does the amperage now make sure you the voltage that we're seeing on it you'll notice that the temperature it's not really going up just the capacitor doing its job 213 volt supply to Cross Fit capacitors not heating up just got power going in and out of it because that's how a capacitor works it wouldn't really matter if I connected a motor to it or not that's not going to change what it does other than the voltage the back EMF being applied from the motor so if you measure that applied voltage across those terminals and you know the capacitance of the capacitor then you're gonna essentially know the amperage you know what it's going to be if you think about the capacitor equation that we use for calculating capacitance it's you take the amperage right of the of the start winding you multiply by 26:52 and then you divide it by the voltage and it gives you the capacitance of that capacitor it's in the 60 Hertz application and so if you work that math any other way you can see that if the capacitance is known if you already know what the capacitance capacitance that the capacitor is and you know the voltage and you already know what the amperage will be what that tells you is is that starting up a motor or basically anything that motor does that's not going to affect the number of electrons that that capacitor can hold oh the only thing that will affect it is the voltage and so as a motor ramps up that's when the back EMF comes into play that's when you get that back electromotive force you don't see that back electromotive force until the motor starts to speed up and so a motor that's short cycling or that's having a hard time starting is not going to cause a capacitor to have more current and without that how could the capacitor heat up the only thing that can cause the capacitor to heat up our external conditions like if you have a run terminal that's also connected on the c terminal of your capacitor and then that's a point of heat or if it's in a hot environment to begin with for example if you have a condenser fan motor that's failing and because of that your entire condenser is running hot well then your capacitor is going to run hot too because of the increased ambient conditions increased temperature around the capacitor so what we know is increases in voltage caused capacitors to fail prematurely and increases in ambient temperature caused capacitors to fail prematurely so the cooler you can keep the capacitor and the more you can keep the voltage near its rating or you obviously below its rating then the better it's gonna last if you get that voltage above its rating then you're gonna start getting bridging it's gonna actually say some of the electrons are going to start to bridge and they're gonna start to damage the internals of the capacitor alright so hopefully you found that helpful a couple things that I want you to know about these run capacitors and how they're tested they're tested to last for 60,000 running hours it's not cycles because in a run capacitor they're in all the time there are no real cycles that unit goes on and off but but you know you're cycling sixty times per second anyway you know your voltage your sine wave is going up and down 60 times per second anyway so turning it on and off isn't the issue it's how many running hours does it run and sixty thousand hours is a long time it's somewhere between you know ten and twenty years depending on what part of the country you're in it's a long time of running typical air conditioner and there's tested so that they should work fine up to 70 degrees Celsius for sixty thousand hours not seventy degrees Fahrenheit so that's 158 degrees Fahrenheit case in point under normal operating conditions capacitor should last a really long time if they're keeping their manufacturer rating if they're actually tested properly and made properly based on the several different standards but that's the or the old u.s. Tecumseh's standard is the sixty thousand hours at seventy degrees Celsius so there's four things that I've identified that can cause run capacitors to fail the number one most common is over voltage and we call these transients that would be power surges a lot of them are caused by lightning down the line from the power company the best way to help reduce transients the best one that exists right now is using a good quality surge suppressor using a you know like not not a cheap you want a good quality surge suppressor is the best way to help prevent those problems with your capacitors because those are gonna help kind of take those voltage transients and shunt them to ground before it gets to your capacitor and again in theory and it depends on the there's a lot of different factors when it comes to these surge suppressors of whether or not they're going to be effective in actually doing that but even small spikes and voltage can cause a run capacitor to fail especially as they accumulate over time because run capacitors they fail small little sections get burned out and then eventually you'll have massive failures so when you see a run paster where it's getting really weak that's what's happened is that segments of that foil on the inside segments of that metal coating have melted off and so you reduce the capacitance over time and you'll see that quite often but the term for the type of search oppressor that I recommend is a thermally protected metal oxide varistor are there better ones out there than that there are some industrial grade surge suppressors that are going to do a little better but a thermally protected metal oxide varistor surge suppressor installed properly with a very short ground on it is the best bet that you're gonna have to protect against these over voltage conditions that are coming down the line now some people have asked can the back EMF from the motor be too high and can that cause it now the answer to that is not really I mean you could have a motor that produces slightly more back EMF because it's running at a really high speed an example would be you have a motor like a compressor that's under a really low load and so it's spinning faster and so it's generating a little bit more back EMF but that still shouldn't be enough to take it over the voltage rating of that capacitor most capacitors we work with and the air conditioning side are 370 or 440 volt ratings it's gonna be pretty rare that you have a voltage failure because of back EMF coming from the motor because again a motor being under greater load because it to run slower will result in less back EMF not more kind of nerdy stuff but some people have asked that question really what it comes down to is the applied voltage down the line getting transients getting voltage spikes down the line and reducing that will help increase the life of a capacitor the next thing is the temperature of the capacitor now like we mentioned here the lower the voltage is applied to the capacitor the longer it will last even when that voltage is decreased below its rating the further below the rating you are the longer the capacitor will last which is why 440 volt capacitors last longer than 370 volt capacitors even if the applied voltage never gets close to 370 the same thing is true with the temperature the cooler you keep a capacitor the longer it's going to last now some people have mentioned that some capacitors are mounted in the air stream and so when that air stream is higher temperature it's going to increase the odds that that capacitor fails the temperature of a capacitor can increase because of all the different types of heat you could have conduction you could have radiation you could have convection all of those things can transfer heat to that capacitor and so when you have a capacitor it's in the condenser Airstream or it's exposed to the condenser if you have a really high condenser temperature because of a dirty condenser that could increase the temperature of that capacitor and again anything that increases the temperature of the capacitor will reduce its life that doesn't mean that it will necessarily make it instantaneously fail because again they're designed for 158 degrees Fahrenheit it's unlikely that you're going to get into that range but it's something for you to at least think about that that is possible and if you think about some things like a like a heat pump for example with a blower capacitor inside the heat pump it's mounted next to the blower you will have cases where that that air can start to approach that temperature anytime you have higher temperature ambient conditions that that capacitor is exposed to whether it's through radiation or conduction or convection then that capacitor life is going to be decreased so we've got over voltage we've got over temperature high ambient temperature can cause it we have installation considerations and so you want to install most capacitors upright and the reason is is because there's a little bit of a void inside that capacitor where there's no oil and if you flip it upside down part of the capacitor windings can be exposed to that void versus when you have it right-side up only the terminals are exposed to that void now it depends on the capacitor manufacturer whether or not that's the case a lot of people have mentioned that a lot of manufacturers place them sideways or upside down I'm not gonna pass judgment on that I'm just telling you that it's a known best practice to mount capacitors right side up another thing is how tight the terminals are on the capacitor so the terminals need to be snug on the capacitor the other thing is if your run winding is using the capacitor as a junction point to get back to the contactor that's also a point that can cause that capacitor to get hot especially if you're having issues with the compressor so if the compressor is short cycling or something like that and you're using the capacitor as a junction point as like that is connecting to that C terminal and then back to the contactor then that can also result in high temperature of the capacitor because that terminal is going to get hot so you want to make sure it's mounted right side up in most cases you want to make sure your connections are really tight and when we'll bring your unwinding connection your unwinding wire right back to the contactor versus taking it to the capacitor and using the capacitor as a junction point and then as it relates to all the other system conditions that could potentially cause it I can't see any reason why under voltage can cause it I can't see any reason why all these other system conditions can cause it other than if the system conditions make the condenser a higher temperature which then causes the capacitor to be a higher temperature I said we've done a lot of testing on this hopefully that's helpful to you gives you some things to look for and maybe some things to do about helping to prevent capacitor failure but the biggest thing you can do is use a high quality capacitor that's why we use imrad and the turbo 200 it's american-made and they do a really nice job testing it alright thanks for watching we'll see you next time [Music] [Applause] [Music]

Channel: HVAC School

Views: 512,997

Keywords: capasitors fail, Why Do Capacitors Fail?, hvac capacitor, hvac fails, capacitor explosion, capacitors, capacitor testing, electrolytic capacitor, hvac, hvac school, hvac training videos, hvac engineer, hvac troubleshooting, hvac technician, hvac design, capacitor testing with digital multimeter, capacitor testing using multimeter, capacitor testing in circuit how to check faulty capacitor, how to, air conditioning, high amp draw, dirty condenser, run capacitors, Capacitance

Id: dVCROCUBxDw

Length: 36min 33sec (2193 seconds)

Published: Fri Jul 06 2018