Superb presentation. With your explanation style, there isn't anyone who cannot understand the topic. Totally gifted teacher with indepth knowledge . Thank you !
Wow, thank you very much. That is such a high compliment! I really like teaching and I enjoy passing that information on to everyone else. Thank you and thank you for watching!
I thank you so much for your comment! I sure am glad I can help you learn other things. I like teaching, I enjoyed and comments like this really motivate me! Thank you for watching!
I've watched a lot of videos on Meg ohm meters and how to use them over the past year. This by far has been the best explanation to help understand exactly what I'm looking for thank you so much
Well! Thank you so much for letting me know. That is why I do this to see if I can simplify things and help the guys out there understand better and hopefully make more money! Good luck and thank you for watching!
I’m sorry and I’m not criticizing, but it drives me crazy when people refer to the “OL” as open line or open lead or the one that really gets me is OVERLOAD. An electrical circuit is simply a loop, no matter how intricate the circuit is, it’s basic form is a loop and OL stands for Open Loop. There, I feel better.. 😀 Great video my man.
HA HA It is funny the things that drive us crazy!!! I know it is a loop and most guys use open lead or open line, they will ague about that. I know it is a loop but I think from now on I will try to add this on to my classes as I go along. "OPEN LOOP". Thank you and I don't mind people making comments about things, I figure it will help me improve what I am doing. Thank you
nice video, iam chasing a ground fault on a 220v motor with a multimeter geting no continuity and OL thinking that the motor is fine when its shorting to ground.
Hi! I hope you found the ground! Sometimes, without a megger, it is next to impossible to find it. I had a chiller compressor that I put in and the supervisor would not get me a megger. As soon as we got our hands on a megger we found out that the brand new compressor was grounded internally. That is why, when the contactor pulled in, the contactor would actually blow up! I hope you found the problem. Thanks for watching!
Right now I'm in quarantine, since I don't have anything to do I was looking for something interesting. I'm glad I found out your channel, the way you explain things is awesome.
Best video I have found on meggers, I'm industrial ammonia refrigeration tech. Thus was a great help explaining meggers for motors, could you please do one on meggers for testing wire?
Thank you so much for your comment! And I appreciate the request on testing wire. I will make a note of this but, please be patient, Unlike a lot of other TH-cam channels I don't make a lot of money here so I have to have another job. But please be patient I will work on making one of these! Thank you very much!!!
Solid video. Very clear and easy to understand. At the end I wish you would have covered phase to phase for windings but still solid video one of if not the best demonstration.
Thanks for the lesson. It would be nice if it was a little shorter. To explain what deci, kilo, mega is, for the average person when you go into that type of detail their eyes glaze over. Maybe start by showing how its done, in under 3 min, then go into details that some people may be interested in doing.
Thank you for your suggestions! This gives me an idea as to what other videos I could make. Some my videos are long because I enjoy teaching and I get carried away. Some of these videos are things that are not even taught in an HVAC classroom so I just get carried away. But thank you for your suggestion and I will see what I can do about that and thank you for watching!
OL, well means open lead or open line some people say, open loop. That means that there is no connection between the two leads that are connected to the meter. So there's basically a bad connection wherever the meter is hooked up. Or the windings in the motor, or the wire that you are testing is broken/open. I hope this answers your question and thank you for watching!
You can run your megger at 500v or 1000v on equipment rated for 120v or 240v. The insulation is usually rated for 600v, ant thats at a high amperage. The megger test is considered non destructive, you arent likely to damage wires by testing with it set at like I say, 500v or 1000v. For a megger that is low.
Pardon my ignorance... if I mag 1000V though motor rated for 460v am I not really putting any current(amps) though it? how would it burn up the insulation... wouldn't think that the meter would send enough current to cause any real damage to the insulation. it's just a thought on my mind.. Other wise great videos will help me a lot. I am trying to understand this as much as possible before I use a megger to diagnose transport refrigeration units that use generators and HV motors, heating strips and compressors.
That is a good question! But there are a couple of things so you need to remember. Amperage the way I explained it in classes is that, that is the amount of electrons flowing through. Voltage is the force and or the pressure that you were pushing the electrons with. When you mentioned the 460 V motor that is the force that you are putting through. It is like when you put too much pressure in a hose that is not designed to take that much pressure. You blow the hose apart. It is not the amount of water going through that destroys it, it is the pressure that blows the hose apart. It is the same thing with a Megger. It is the pressure that blows the insulation apart if you put too much voltage through that motor. In class I compare water to electricity because they work the same. The voltage is the same as pressure and amperage is the same as how much is flowing. I hope this explains the question. I'm not sure if I have a video on TH-cam where I explain all of this about electricity. But I do know I do teach it this Way in class and it makes guys understand it very easily. Good luck!!!!
Great reply.. I have always compared it to water myself.. Definitely cleared that up for me. To be honest I saw videos on TH-cam where they're saying if it's rated for 250v, send 500v..So I was a bit confused. Definitely agree with you. Thank you so much for this sir.
Another outstanding video sir!!!!! I love how you show the actual picture of what the item looks like in the field as you are drawing it. I was wondering if I may ask your input on the low impedance or Loz function on the meters and if it is something us techs should be using more? Thank you again,
Thank you for the compliment and question. The Loz setting can help you find a bad ground or neutral. BUT the problem with that is that if there is hot wire and yo have a bad ground it wills how 0V and someone may think the hot is dead. They may touch it and get shocked. In what we do, meaning HVAC, I do not see us needing it. the ghost readings will happen when there are several wires running through a bundle and some wires are not energized and giving you the false readings. I can see how an electrician would need this but in the HVAC field it is not needed as much. I hope this makes sense. Thank you
@@AirConAcademy Thank you sir for the reply! It makes total sense. I just notice that a lot of new meters seem to be coming out with the Loz setting, so I thought I would ask. Thanks again, I really appreciate it.
Thankyou, for the clear explanation . However, aren't you supposed to double the voltage using a megger? Or will that create a breakthrough in insulation?
I don't like doubling the voltage. remember, your own meter is only using that 9 V battery. The meager will send 500 V 480 V motor. I know some people do double it so you could go up to 1000 volts. Thank you for watching!
Love the explanation on your videos!! I have a question for you. How often do you recommend testing a compressor motor on a chiller using a megohmmeter?
Thank you for your kind words!!! I am glad to help so many out there. Meggers sometimes put a strain in the motors, if it is not done right. We used to test motors once a year. So that is what I would suggest. It is very important to keep a record of the past readings so when there is a drastic change it can be seen and something can be done about it. good luck!!!
You are the second or third person that has asked about oil pressure switches. I need to make one on that but I need the time. Unfortunately I still have to work so it takes me time to do all of this and work! I do have a note made to make a video on oil pressure switches so keep watching and you will see one! Thank you!
Nice thank you. How are you behind the board and we don't see you writing backwards.? I do have a motor question though. How a turn to turn short is diagnosed when not shorted to chassis, on a single phase 120-220 VAC motor? Motors works but pulls a bit more amp. I can guess after eliminating everything maybe a turn to turn short. But Old love to know how and what instrument can diagnose this problem and be certain of diagnostic to a good measure.
When I started the videos I was writing backwards. But then I realized that I can write normal and just flip the video around so it looks correct. And I am writing on a piece of glass so that you guys can see me and what I am writing. It's kind of interesting how it works. Now ask for your motor. It sounds like you are correct and you have a short from a turn to a turn as you put it. There is really no easy way to be sure except to have a motor exactly like the one that you have, compare your readings on this bad motor to the readings on the good motor. If your resistance, or in other words of the OHMs readings on the motor that is drawing high amps are low then that means you have a short from turn to turn. There is really no other way other than comparing it to another motor. The resistance in the windings should be the same on a brand new motor as long as the motor is just like the one that you have. I hope this helps. And good luck!
@@AirConAcademy thank you very much. This is very helpful. So when imagining a good winding it seems as a winding road all the way through and a winding with a turn to turn short would have some sort of a Lupe or a short cut along the route. Measuring and comparing resistance would be one way for sure. How about if there's an instruments that would measure exact length of wire but again I would have to compare it to a length of the winding of a good motor.
@@AB-yu2tj if you have a short return to turn that would make the resistance less. And as far as I know there is no instrument for reading the length of the wire. I have used the comparison method many of times. And after a while when you deal with the same type of motors and compressors you get used to what the readings should be for that voltage and tonnage of compressor. I usually tell the guys in class to write down the resistance for the brand new motor and or compressor, if possible on the motor or compressor itself so you have something to compare it to in the future. That last part I just learned from experience because doing this from 1979 to now you end up finding ways of making your life easier. Lol I hope this helps and good luck out there!
@@AirConAcademy so here's the update on what I've found so far which seems to be capable of diagnosing turn to turn shorts but I still have to do more research to see if I have to compare its readings to reading off of a good winding. Or will it do the job on its own. Ninety-nine percent of the time I'm testing single phase 220 volts Motors. It's called Motor Genie. I think it's made by All Test
Hi Julio, thanks for all your vidos. Qestion: I have a 24 Volt motor, can I use a megger to check if motor is in good condition? greetings from Trondheim, Norway. Sverre eriksen.
I was just telling someone else that there are so many different configurations of all of these components out there. To be honest with you I have never seen a 24 V motor? Solenoids yes but never a motor.? I suppose if you set the voltage of the Megger to the lowest setting you could test it, small motors we usually do not go through the trouble of using a megger. I'm not sure if this helps any. But I just have never seen a 24 V motor.
@@AirConAcademy thanks Julio, This little motor on 24 Volts is tested ,and seemed to be ok. I applied the volts from a industrial batteri. The motor is from a expresso coffemaskin and about 10 cm long. I am following almost all of yours vidoes, so clearly explained. Sorry for my English. mvh Sverre Eriksen.
@@sverreeriksen1982 do not worry about the language barrier. I know it is tough communicating with someone that speaks a different language than you do. Thank you for your comments about my videos. I understand you applied voltage from an industrial battery. Some motors will not work on voltage coming from a battery because that is direct current/DC, most motors need alternating current/AC. It probably did not work when you hooked it up to the battery because of that. As before I'm not familiar with that type of machine, but motors operate the same way no matter where they are being used. So if this is a 24 V AC motor it will not work with DC. If it is a DC motor then you may want to check the brushes and see if they are in good shape. I am not sure if I have any videos on DC motors yet. But check to see if it is AC or DC current.
That's an interesting question? I have never heard of a measure being used on solar panels. This is mostly used to check the insulation on motor windings or generator windings. Solar panels are solid state devices that do not have the same type of insulation on them. I will look into it but as far as I know meggers are not used on solar panels. Thank you for watching!!!
If a motor is 460V isn’t that an RMS voltage value? Wouldn’t the peak of the sine be around 700 volts meaning that the winding insulation should be able to safely handle that amount of voltage? I was taught to use double of the voltage rating of the motor I’m testing. Correct me if I’m wrong but since the current meggers put out is so low it makes these test nondestructive.
I don't like taking a chance on destroying things. Yes, some people teach to double the voltage. In class I always tell the students that windings on a motor or wire it's just like a garden hose. You increase the pressure too much, meaning the voltage it could blow someplace. We know that voltage is leaking out at 460 V, so I mega should be able to detect it if you said it to 500 V setting. Like I said before, I don't like taking a chance on destroying things, and I don't want to come back and tell my supervisor I was making a motor and put too much voltage through it and grounded it. Yes, I have seen it happen. Good luck. I hope this helps! And thank you for watching!
@@AirConAcademy I’ll have to disagree with you on megger test voltages. A megger is a non destructive test instrument. It cannot generate enough amperage ( 5ma max short circuit current), to cause damage to a motor winding. Think of it as static electricity. It can jump an ark but it won’t damage the motor windings. I use AEMC industrial crank type meggers, The instructions for voltage to set the meter at is as follows: Rated voltage of motors below 115, use test voltage of 250 volts, Rated voltage of motors 115 volts, use test voltage of 250 or 500, motors rated at 230 volts, use test voltage of 500V. Motors rated at 460, use 500 or 1000. I have used these recommendations, for testing motor insulation for years, and have never damaged any motor. I agree that you would never apply line voltage POWER in excess of a motors rated voltage, but megger test voltage is not the same. Of course, I would never megger any motor thermistor, or electronic motor control component.
@@rodgraff1782 Yes, those are the instructions that are found in the megger manual. I was using my opinion in the previous answer. If the manufacturer of the Megger said you can do that I would never dispute it. It is like when I'm teaching an Air Conditioning class, we typically teach that superheat should be 8 to 12°. Then I tell the students if the manufacturer says that it should be 6, who knows better? Me the INSTRUCTOR or the manufacturer. And I make sure that they understand that the manufacture knows best and to follow the manufacturer instructions. I was not trying to confuse anyone. I just wanted them to be careful because I have heard of that happening to the electricians when they are Megging a motor. Thank you for your comment!
The stater has the windings, yes, but the electricity is staying inside the wire because of the insulation around the wire. All of the wire that you see in the stater is coated with clear lacquer/varnish. So as the current passes through it stays inside the insulation and does not leak out. If it did leak out it would go through to the ground wire to ground. And this would be a problem that we call, a ground. I hope this explains your question.
So im new to using a megger and im not sure the person teaching me even has a clue especially after watching this video. He told me on checking a 480 volt motor you set the megger to 1000 volts and if it ready all its good. This is using i believe a fluke 1507 megger. Any feedback would be appreciated.
The motor windings and the insulation is set up to the specific voltage. I do not like putting a too high voltage because it is like adding too much pressure and it could blow the insulation, like raising the pressure in a hose, it could blow the house apart if the pressure is too high. That is why a MEGGER has different voltage settings, so you can set it to a voltage close to operating voltage. If you look at your meter it has different settings for different voltages, so you can check different voltage motors. This is the link to the user manual for your meter. dam-assets.fluke.com/s3fs-public/1507____umeng0100.pdf?Eu5rEtlCCr4HEG1nvkhUL9AUrbzm3fSc On your own test motors and take your time. good luck!!!
Hello, the manual will never tell you what to put the meter at. The person showed you is correct. It should be double the voltage. If you meg a motor that is 460v , what kind of pressure test is it to put it to 500v. It should be out at 1000v. That what the test is, to put it under pressure to make it fail if there it is compromised or show signs of failure.
Remember this is a controlled test in a testing environment. For example if you lose one phase on a three-phase motor your voltage will go up approximately 78%. The recommended test voltage for insulation resistance testing is typically higher than the rated voltage of the motor. A common practice is to use a test voltage that is approximately double the rated voltage of the motor. For a 460-volt AC motor, a test voltage of around 1000 volts is often suitable. Using a higher test voltage helps ensure that the insulation is capable of withstanding potential overvoltage conditions during normal operation. It provides a more robust evaluation of the insulation resistance and helps identify any weaknesses or potential issues. Remember, just don't watch TH-cam videos for information on your career. Look under standards from NFPA, ANSI, IEEE, NEC etc. best of luck.
I am a technician that work on refrigeration beverage and cooking equipment do you have any courses that would help me be more proficient in my line of work
At the moment I have the videos here on TH-cam, and the courses on my webpage. airconacademy.com I don't have anything specifically on the equipment you work on, I put these videos out hoping that it would help guys and different parts of this field!
Sir I want to know what type of control panel we use in our HVAC system.for example I m working on Trane air coold chiller and I don't have any knowledge about its panel system.plz make a video on this topic
If I should meg a motor rated 230 Volt, would I then set the megger to: 500 or 250 Volt.? would 500 Volt ruin the insulation in the motor? Thank you for clearly explanation. I do like your vidios. Live in Trondheim , NORWAY. mvh sverre eriksen.
It would be a good idea to set the voltage to, 250 V. If you go to 500 you may ruin the insulation. I only Meg motors if it is necessary. Sometimes Megan a motor could where the insulation out sooner. Thank you for watching the videos and hello to you over there in Norway! I am here close to Washington DC!
It actually wouldn’t matter since you’re using a minimal amount of current and the insulation and resistance tester is non intrusive/destructive. And the wiring is usually rated to handle over double the voltage rating
That's a very good question! I typically explain this in class. The generators at the power plant are grounded to an earth ground, meaning that they are connected to ground. Transformers are also connected to ground and because of that electricity always wants to go to ground because it wants to go back to the source as you put it. If the generators were not grounded then electricity would not go to ground. I guess you could say it is all semantics. I hope this explained it for you. Thanks for watching!!!!
They are 2 different things. In single phase AC, The return path is back to its source, either the other phase or neutral. Ground is used for safety. In case something happens where the case gets energized, it trips a safety device and nobody gets hurt.
@@robertrappuchi5743 yes, you're right. It needs to go back to the source whether it is through neutral or the other hot leg. And yes, ground is for safety. And like I tell everyone in class it is the most important wire because that could save your life. thank you
Awesome you just save me I was arguing with a mechanic lol he told the motor was bad turned out it was good 👍 he was using the wrong size belts causing the motor to work harder then it should thanks buddy freaking bigass 480 v 20 hp lol
I have heard that method before, doubling the voltage. I was tell everyone to remember voltage is the pressure pushing the electrons, if you increase the voltage too much, then you may blow a hole in the insulation and prematurely destroy the motor. As long as you have never destroyed a motor, I guess your method would work! Thank you for your comment. And thank you for watching !!!
@@ld7103 My megger puts out rectified DC voltage of 250, 500, or 1000 volts, generated by an on board hand crank generator. Even if there was a direct short to ground,it can only produce 5 milliamperes or less. No way could that damage motor windings, even at two or three times the rated motor voltage.
Riding backwards is something that I have been able to do for a long time. But sometimes I just flip the video around. That is my trade secret! Don't be telling everybody! Lol ha ha ha. Thank you for watching!
it can stop and if it stops you die. but you may not. yes it depends on a lot of things BUT if I tell people that they will not die and they do it will not be a good thing!!! but yes it all depends on things
Its not a Megger, a Megger is a Trade Name that makes a insulation tester, that has arrange of mega ohms. Second point if a meter has a 9V battery does a insulation tester have a 500V battery.
My intention is not to confuse anyone so I'm using the term that they will be familiar with. Yes, some will have a 9 V battery in them, some. And I guess if you hook up enough batteries together you could have a 500 V battery. They are converting the nine volts to a higher voltage very similar to how they do it in a car. The car has a 12 V battery but they raise the voltage into the thousands for the spark-plugs to ignite the fuel. When I started doing this back in 1979 we used the Meggers that had a crank on them, in other words they had a mini generator inside. I hope this explains some of it to you. Thank you for your comment. Be careful out there and keep learning!
As an industrial electrician of 41 years we always called a megohmmeter or insulation tester a Megger for short.Hardly anybody ever called it a megohmmeter or insulation tester. Like you said Megger is just a trade name that makes insulation testers.
Ha ha ha! Yes! That will usually show you where the problem is. It is one of those one way troubleshooting ways and sometimes there is no coming back from there lol thanks a lot that was great! And thank you for watching!
Superb presentation. With your explanation style, there isn't anyone who cannot understand the topic. Totally gifted teacher with indepth knowledge . Thank you !
Wow, thank you very much. That is such a high compliment! I really like teaching and I enjoy passing that information on to everyone else. Thank you and thank you for watching!
Was in the trade forty five years, I learn something every time I watch one of your lessons. Thank You so much for doing this.
I thank you so much for your comment! I sure am glad I can help you learn other things. I like teaching, I enjoyed and comments like this really motivate me! Thank you for watching!
I've watched a lot of videos on Meg ohm meters and how to use them over the past year. This by far has been the best explanation to help understand exactly what I'm looking for thank you so much
Wow, thank you so much for your comment! I'm glad you liked it and thank you for watching!
Really good job a explaining this. Impressed at how you did all the writing backwards and still pulled it off. Thank you.
thank you and thank you for watching!!!
great explanation, i was very confused, now i understand better
Well! Thank you so much for letting me know. That is why I do this to see if I can simplify things and help the guys out there understand better and hopefully make more money! Good luck and thank you for watching!
I’m sorry and I’m not criticizing, but it drives me crazy when people refer to the “OL” as open line or open lead or the one that really gets me is OVERLOAD. An electrical circuit is simply a loop, no matter how intricate the circuit is, it’s basic form is a loop and OL stands for Open Loop. There, I feel better.. 😀 Great video my man.
HA HA It is funny the things that drive us crazy!!! I know it is a loop and most guys use open lead or open line, they will ague about that. I know it is a loop but I think from now on I will try to add this on to my classes as I go along. "OPEN LOOP". Thank you and I don't mind people making comments about things, I figure it will help me improve what I am doing. Thank you
Your OCD is worst than mine.
When I bought my Fluke 88 many years ago, the manual states that OL means Overload condition is detected. Makes no sense to me either!
Over Limit. As in Over the Limit of the testers capability.
So it doesn't mean to take lunch?- "On Lunch"
Great Teacher! Love the way you present.
nice video, iam chasing a ground fault on a 220v motor with a multimeter geting no continuity and OL thinking that the motor is fine when its shorting to ground.
Hi! I hope you found the ground! Sometimes, without a megger, it is next to impossible to find it. I had a chiller compressor that I put in and the supervisor would not get me a megger. As soon as we got our hands on a megger we found out that the brand new compressor was grounded internally. That is why, when the contactor pulled in, the contactor would actually blow up! I hope you found the problem. Thanks for watching!
I like your teaching, it me to better understand in a common way.
Thank you! I am glad you like it. I like to simplify things because I know how difficult it was for me.
Thank you for watching!
thank you for taking the time and explaining it so well
Thank you for watching I am glad you liked it!!!
Professional teaching, I love it thanks you.
Thank you! I'm glad you like the video and thank you for watching!
Right now I'm in quarantine, since I don't have anything to do I was looking for something interesting. I'm glad I found out your channel, the way you explain things is awesome.
Thank you! I cant imagine being quarantined!!! I have been busy, but hope to have more videos up soon!
Best video have watched so far on this topic.....bravo
Thank you so much! I'm glad you like the video. I hope you can watch the other ones I have on here!
By far the best explanation out here
Thank you so much! And thank you for watching!
Very well explained sir and hatsoff to your ambidextrous skills
Thank you very much! And yes, it is fun being able to do that!
I wasn't the only one who picked up on that
That is one killer gift to have
Best video I have found on meggers, I'm industrial ammonia refrigeration tech. Thus was a great help explaining meggers for motors, could you please do one on meggers for testing wire?
Thank you so much for your comment! And I appreciate the request on testing wire. I will make a note of this but, please be patient, Unlike a lot of other TH-cam channels I don't make a lot of money here so I have to have another job. But please be patient I will work on making one of these! Thank you very much!!!
Solid video. Very clear and easy to understand. At the end I wish you would have covered phase to phase for windings but still solid video one of if not the best demonstration.
Thank you so much! And maybe I can make another video where I can talk about that. Good luck out there!
super info on megger, this man explain so good , you have to understand. want more of this.
Thank you!!! I keep trying but so much to do and so little time! Thank you!!!
Very best explanation! Thank u Julio!
Thank you so much! And thank you for watching!
Thanks for the lesson. It would be nice if it was a little shorter. To explain what deci, kilo, mega is, for the average person when you go into that type of detail their eyes glaze over. Maybe start by showing how its done, in under 3 min, then go into details that some people may be interested in doing.
Thank you for your suggestions! This gives me an idea as to what other videos I could make. Some my videos are long because I enjoy teaching and I get carried away. Some of these videos are things that are not even taught in an HVAC classroom so I just get carried away. But thank you for your suggestion and I will see what I can do about that and thank you for watching!
thank you sir . OL means the voltage you tested is larger than the motor voltage which can destroy the motor insulation right, sir?
OL, well means open lead or open line some people say, open loop. That means that there is no connection between the two leads that are connected to the meter. So there's basically a bad connection wherever the meter is hooked up. Or the windings in the motor, or the wire that you are testing is broken/open. I hope this answers your question and thank you for watching!
Excellent explanation 🎉
Thank you so much for your kind words! And thank you for watching!
Learnt so much in that video. Thanks mate
Thank you so much! I'm so glad to hear that!
Thank you for watching!
Well good explanation but didn’t mention a megger is a brand that makes insulation meters
oops I guess I did miss that part. Thank you and thank you for watching!!!
Great teaching.
Thank you so much! And thank you for watching!
Awesome, best explanation ever.
Thank you so much! And thank you for watching!
Thank you for an outstanding explanation.
Thank you so much. I am glad you liked it!!!
Thank you very instructive. Thank you Julio for your teaching God bless take care. Stay safe from covi
Thank you so much and you too stay safe!!!
You can run your megger at 500v or 1000v on equipment rated for 120v or 240v. The insulation is usually rated for 600v, ant thats at a high amperage. The megger test is considered non destructive, you arent likely to damage wires by testing with it set at like I say, 500v or 1000v. For a megger that is low.
Thank you for this video good job explaining this topic
Thank you! I'm glad you liked it and thank you for watching!
Pardon my ignorance... if I mag 1000V though motor rated for 460v am I not really putting any current(amps) though it? how would it burn up the insulation... wouldn't think that the meter would send enough current to cause any real damage to the insulation. it's just a thought on my mind.. Other wise great videos will help me a lot. I am trying to understand this as much as possible before I use a megger to diagnose transport refrigeration units that use generators and HV motors, heating strips and compressors.
That is a good question! But there are a couple of things so you need to remember. Amperage the way I explained it in classes is that, that is the amount of electrons flowing through. Voltage is the force and or the pressure that you were pushing the electrons with. When you mentioned the 460 V motor that is the force that you are putting through. It is like when you put too much pressure in a hose that is not designed to take that much pressure. You blow the hose apart. It is not the amount of water going through that destroys it, it is the pressure that blows the hose apart. It is the same thing with a Megger. It is the pressure that blows the insulation apart if you put too much voltage through that motor. In class I compare water to electricity because they work the same. The voltage is the same as pressure and amperage is the same as how much is flowing. I hope this explains the question. I'm not sure if I have a video on TH-cam where I explain all of this about electricity. But I do know I do teach it this Way in class and it makes guys understand it very easily. Good luck!!!!
Great reply.. I have always compared it to water myself.. Definitely cleared that up for me.
To be honest I saw videos on TH-cam where they're saying if it's rated for 250v, send 500v..So I was a bit confused. Definitely agree with you. Thank you so much for this sir.
@@tnt666tnt I'm glad he cleared it up. Good luck out there!
Another outstanding video sir!!!!! I love how you show the actual picture of what the item looks like in the field as you are drawing it. I was wondering if I may ask your input on the low impedance or Loz function on the meters and if it is something us techs should be using more? Thank you again,
Thank you for the compliment and question. The Loz setting can help you find a bad ground or neutral. BUT the problem with that is that if there is hot wire and yo have a bad ground it wills how 0V and someone may think the hot is dead. They may touch it and get shocked. In what we do, meaning HVAC, I do not see us needing it. the ghost readings will happen when there are several wires running through a bundle and some wires are not energized and giving you the false readings. I can see how an electrician would need this but in the HVAC field it is not needed as much. I hope this makes sense. Thank you
@@AirConAcademy Thank you sir for the reply! It makes total sense. I just notice that a lot of new meters seem to be coming out with the Loz setting, so I thought I would ask. Thanks again, I really appreciate it.
Thank U very much for this video.i would be watching it again .God Bless and stay safe.
Thank you!!!
Good lesson ! Good teaching style
Thank you! And thank you for watching!
Thankyou, for the clear explanation . However, aren't you supposed to double the voltage using a megger? Or will that create a breakthrough in insulation?
I don't like doubling the voltage. remember, your own meter is only using that 9 V battery. The meager will send 500 V 480 V motor. I know some people do double it so you could go up to 1000 volts. Thank you for watching!
Looking for how to use a megger.. the batman shirt lured me in... lol
Ha ha! I'm glad the shirt got your attention but I hope it helped you understand makers.! Thank you for your comment!
Love the explanation on your videos!! I have a question for you. How often do you recommend testing a compressor motor on a chiller using a megohmmeter?
Thank you for your kind words!!! I am glad to help so many out there. Meggers sometimes put a strain in the motors, if it is not done right. We used to test motors once a year. So that is what I would suggest. It is very important to keep a record of the past readings so when there is a drastic change it can be seen and something can be done about it. good luck!!!
Nice lesson and very well explained
Thank you so much for your comment, and thank you for watching!
Great explanation, would it be possible to do a video on oil pressure switches?
You are the second or third person that has asked about oil pressure switches. I need to make one on that but I need the time. Unfortunately I still have to work so it takes me time to do all of this and work! I do have a note made to make a video on oil pressure switches so keep watching and you will see one! Thank you!
@@AirConAcademy Thankyou
Nice thank you. How are you behind the board and we don't see you writing backwards.?
I do have a motor question though.
How a turn to turn short is diagnosed when not shorted to chassis, on a single phase 120-220 VAC motor?
Motors works but pulls a bit more amp. I can guess after eliminating everything maybe a turn to turn short. But Old love to know how and what instrument can diagnose this problem and be certain of diagnostic to a good measure.
When I started the videos I was writing backwards. But then I realized that I can write normal and just flip the video around so it looks correct. And I am writing on a piece of glass so that you guys can see me and what I am writing. It's kind of interesting how it works. Now ask for your motor. It sounds like you are correct and you have a short from a turn to a turn as you put it. There is really no easy way to be sure except to have a motor exactly like the one that you have, compare your readings on this bad motor to the readings on the good motor. If your resistance, or in other words of the OHMs readings on the motor that is drawing high amps are low then that means you have a short from turn to turn. There is really no other way other than comparing it to another motor. The resistance in the windings should be the same on a brand new motor as long as the motor is just like the one that you have. I hope this helps. And good luck!
@@AirConAcademy thank you very much. This is very helpful.
So when imagining a good winding it seems as a winding road all the way through and a winding with a turn to turn short would have some sort of a Lupe or a short cut along the route.
Measuring and comparing resistance would be one way for sure. How about if there's an instruments that would measure exact length of wire but again I would have to compare it to a length of the winding of a good motor.
@@AB-yu2tj if you have a short return to turn that would make the resistance less. And as far as I know there is no instrument for reading the length of the wire. I have used the comparison method many of times. And after a while when you deal with the same type of motors and compressors you get used to what the readings should be for that voltage and tonnage of compressor. I usually tell the guys in class to write down the resistance for the brand new motor and or compressor, if possible on the motor or compressor itself so you have something to compare it to in the future. That last part I just learned from experience because doing this from 1979 to now you end up finding ways of making your life easier. Lol I hope this helps and good luck out there!
@@AirConAcademy thank you very much
@@AirConAcademy so here's the update on what I've found so far which seems to be capable of diagnosing turn to turn shorts but I still have to do more research to see if I have to compare its readings to reading off of a good winding. Or will it do the job on its own. Ninety-nine percent of the time I'm testing single phase 220 volts Motors.
It's called Motor Genie. I think it's made by All Test
Hi Julio, thanks for all your vidos. Qestion: I have a 24 Volt motor, can I use a megger to check if motor is in good condition? greetings from Trondheim, Norway. Sverre eriksen.
I was just telling someone else that there are so many different configurations of all of these components out there. To be honest with you I have never seen a 24 V motor? Solenoids yes but never a motor.? I suppose if you set the voltage of the Megger to the lowest setting you could test it, small motors we usually do not go through the trouble of using a megger. I'm not sure if this helps any. But I just have never seen a 24 V motor.
@@AirConAcademy thanks Julio, This little motor on 24 Volts is tested ,and seemed to be ok. I applied the volts from a industrial batteri. The motor is from a expresso coffemaskin and about 10 cm long. I am following almost all of yours vidoes, so clearly explained. Sorry for my English. mvh Sverre Eriksen.
@@sverreeriksen1982 do not worry about the language barrier. I know it is tough communicating with someone that speaks a different language than you do. Thank you for your comments about my videos. I understand you applied voltage from an industrial battery. Some motors will not work on voltage coming from a battery because that is direct current/DC, most motors need alternating current/AC. It probably did not work when you hooked it up to the battery because of that. As before I'm not familiar with that type of machine, but motors operate the same way no matter where they are being used. So if this is a 24 V AC motor it will not work with DC. If it is a DC motor then you may want to check the brushes and see if they are in good shape. I am not sure if I have any videos on DC motors yet. But check to see if it is AC or DC current.
How is this used in checking solar panel installs?
That's an interesting question? I have never heard of a measure being used on solar panels. This is mostly used to check the insulation on motor windings or generator windings. Solar panels are solid state devices that do not have the same type of insulation on them. I will look into it but as far as I know meggers are not used on solar panels. Thank you for watching!!!
We use meggers @ the job site. Always good to have a REFRESHER.
Mongo Slade Thank you! I’m glad you think so. I’m glad I could help.
If a motor is 460V isn’t that an RMS voltage value? Wouldn’t the peak of the sine be around 700 volts meaning that the winding insulation should be able to safely handle that amount of voltage? I was taught to use double of the voltage rating of the motor I’m testing. Correct me if I’m wrong but since the current meggers put out is so low it makes these test nondestructive.
I don't like taking a chance on destroying things. Yes, some people teach to double the voltage. In class I always tell the students that windings on a motor or wire it's just like a garden hose. You increase the pressure too much, meaning the voltage it could blow someplace. We know that voltage is leaking out at 460 V, so I mega should be able to detect it if you said it to 500 V setting. Like I said before, I don't like taking a chance on destroying things, and I don't want to come back and tell my supervisor I was making a motor and put too much voltage through it and grounded it. Yes, I have seen it happen. Good luck. I hope this helps! And thank you for watching!
@@AirConAcademy I’ll have to disagree with you on megger test voltages. A megger is a non destructive test instrument. It cannot generate enough amperage ( 5ma max short circuit current), to cause damage to a motor winding. Think of it as static electricity. It can jump an ark but it won’t damage the motor windings. I use AEMC industrial crank type meggers, The instructions for voltage to set the meter at is as follows: Rated voltage of motors below 115, use test voltage of 250 volts, Rated voltage of motors 115 volts, use test voltage of 250 or 500, motors rated at 230 volts, use test voltage of 500V. Motors rated at 460, use 500 or 1000. I have used these recommendations, for testing motor insulation for years, and have never damaged any motor. I agree that you would never apply line voltage POWER in excess of a motors rated voltage, but megger test voltage is not the same. Of course, I would never megger any motor thermistor, or electronic motor control component.
@@rodgraff1782 Yes, those are the instructions that are found in the megger manual. I was using my opinion in the previous answer. If the manufacturer of the Megger said you can do that I would never dispute it. It is like when I'm teaching an Air Conditioning class, we typically teach that superheat should be 8 to 12°. Then I tell the students if the manufacturer says that it should be 6, who knows better? Me the INSTRUCTOR or the manufacturer. And I make sure that they understand that the manufacture knows best and to follow the manufacturer instructions. I was not trying to confuse anyone. I just wanted them to be careful because I have heard of that happening to the electricians when they are Megging a motor. Thank you for your comment!
Great Job brother
Thank you very much! I'm glad you like the video! I hope I can get more out there for you guys!
Please explain the external and internal expansion valve.. I understand your efforts.. Thanks.
Thank you for the suggestion! I had not thought about doing that but that is a good idea! Thank you.
Thank you very much!
thank you and thank you for watching !!!
when motor is running why stator is not give any shock .why im asking, stator also has winding with current passing,
The stater has the windings, yes, but the electricity is staying inside the wire because of the insulation around the wire. All of the wire that you see in the stater is coated with clear lacquer/varnish. So as the current passes through it stays inside the insulation and does not leak out. If it did leak out it would go through to the ground wire to ground. And this would be a problem that we call, a ground. I hope this explains your question.
So im new to using a megger and im not sure the person teaching me even has a clue especially after watching this video. He told me on checking a 480 volt motor you set the megger to 1000 volts and if it ready all its good. This is using i believe a fluke 1507 megger. Any feedback would be appreciated.
The motor windings and the insulation is set up to the specific voltage. I do not like putting a too high voltage because it is like adding too much pressure and it could blow the insulation, like raising the pressure in a hose, it could blow the house apart if the pressure is too high. That is why a MEGGER has different voltage settings, so you can set it to a voltage close to operating voltage. If you look at your meter it has different settings for different voltages, so you can check different voltage motors. This is the link to the user manual for your meter. dam-assets.fluke.com/s3fs-public/1507____umeng0100.pdf?Eu5rEtlCCr4HEG1nvkhUL9AUrbzm3fSc On your own test motors and take your time. good luck!!!
Hello, the manual will never tell you what to put the meter at. The person showed you is correct. It should be double the voltage. If you meg a motor that is 460v , what kind of pressure test is it to put it to 500v. It should be out at 1000v. That what the test is, to put it under pressure to make it fail if there it is compromised or show signs of failure.
The NETA test specifically 2005 governs the DC voltage for insulation test for 600 volt class equipment as 1000VDC.
Remember this is a controlled test in a testing environment. For example if you lose one phase on a three-phase motor your voltage will go up approximately 78%.
The recommended test voltage for insulation resistance testing is typically higher than the rated voltage of the motor. A common practice is to use a test voltage that is approximately double the rated voltage of the motor. For a 460-volt AC motor, a test voltage of around 1000 volts is often suitable.
Using a higher test voltage helps ensure that the insulation is capable of withstanding potential overvoltage conditions during normal operation. It provides a more robust evaluation of the insulation resistance and helps identify any weaknesses or potential issues.
Remember, just don't watch TH-cam videos for information on your career. Look under standards from NFPA, ANSI, IEEE, NEC etc. best of luck.
Excelent instructor!!
Thank yo so much!!! I really appreciate your kind words!!! Thank you for watching!!!
I am a technician that work on refrigeration beverage and cooking equipment do you have any courses that would help me be more proficient in my line of work
At the moment I have the videos here on TH-cam, and the courses on my webpage. airconacademy.com I don't have anything specifically on the equipment you work on, I put these videos out hoping that it would help guys and different parts of this field!
Really smart teacher here
Thank so much!!! and thank you for watching!!!
Sir I want to know what type of control panel we use in our HVAC system.for example I m working on Trane air coold chiller and I don't have any knowledge about its panel system.plz make a video on this topic
I will see what I can do. I think you are saying what the wiring might be like in the chiller you are using? and how the controls are set up?
Chiller are CGAV428 SERIES make 1994 and mostly I want to know about AHU FLOOR MOUNTED CONTROL PANEL system.THANKS SO MUCH
Great Video!
Thank you so much! I'm glad you like the video!
Is there a ohm chart for motors winding?to check for a value resistance on a 480v or 208v motor
Sometimes the manufacturers will have that information out there. I have found it but it is hard to find. sorry.
If I should meg a motor rated 230 Volt, would I then set the megger to: 500 or 250 Volt.? would 500 Volt ruin the insulation in the motor? Thank you for clearly explanation. I do like your vidios. Live in Trondheim , NORWAY. mvh sverre eriksen.
It would be a good idea to set the voltage to, 250 V. If you go to 500 you may ruin the insulation. I only Meg motors if it is necessary. Sometimes Megan a motor could where the insulation out sooner. Thank you for watching the videos and hello to you over there in Norway! I am here close to Washington DC!
It actually wouldn’t matter since you’re using a minimal amount of current and the insulation and resistance tester is non intrusive/destructive. And the wiring is usually rated to handle over double the voltage rating
!
You join my short list of Best HVAC instructors.
Thank you!
Thank you!!! I appreciate it!!!
This is so educative
I thank you so much for your comment! And thank you for watching!
Great job 👍
Thank you! I'm glad you liked the video!
Excellent - thank you!
Thank you for watching!!!
Is it semantics or is electricity “ going to ground” or “ trying to return to its source? Thank you for the vids.
That's a very good question! I typically explain this in class. The generators at the power plant are grounded to an earth ground, meaning that they are connected to ground. Transformers are also connected to ground and because of that electricity always wants to go to ground because it wants to go back to the source as you put it. If the generators were not grounded then electricity would not go to ground. I guess you could say it is all semantics. I hope this explained it for you. Thanks for watching!!!!
They are 2 different things. In single phase AC, The return path is back to its source, either the other phase or neutral. Ground is used for safety. In case something happens where the case gets energized, it trips a safety device and nobody gets hurt.
@@robertrappuchi5743 yes, you're right. It needs to go back to the source whether it is through neutral or the other hot leg. And yes, ground is for safety. And like I tell everyone in class it is the most important wire because that could save your life. thank you
Awesome you just save me I was arguing with a mechanic lol he told the motor was bad turned out it was good 👍 he was using the wrong size belts causing the motor to work harder then it should thanks buddy freaking bigass 480 v 20 hp lol
I am so glad I could help!!!! I love it when you guys can prove someone wrong!!! thanks for watching!!!.
I was always taught to set to double the voltage used
I have heard that method before, doubling the voltage. I was tell everyone to remember voltage is the pressure pushing the electrons, if you increase the voltage too much, then you may blow a hole in the insulation and prematurely destroy the motor. As long as you have never destroyed a motor, I guess your method would work! Thank you for your comment. And thank you for watching !!!
@@AirConAcademy appreciate response 👍
@@ld7103 My megger puts out rectified DC voltage of 250, 500, or 1000 volts, generated by an on board hand crank generator. Even if there was a direct short to ground,it can only produce 5 milliamperes or less. No way could that damage motor windings, even at two or three times the rated motor voltage.
Good stuff.
Thank you! I'm glad you liked the video. And thank you for watching!
Nicely covered
Thank you I am glad I could help!
so how exactly do you write backwards with no effort?
Riding backwards is something that I have been able to do for a long time. But sometimes I just flip the video around. That is my trade secret! Don't be telling everybody! Lol ha ha ha. Thank you for watching!
Excellent sir but can u plz explain the part winding and start winding with internal connection plzzz
Sir plz explain about lockout relay.
Very imformative
Thank you! I'm glad you liked the video and hope it helps you out out there!
Good video
Thank you!!!! Glad you liked it!!!!
you mena your heart CAN stop...if you touch that casing, its not like you die for sure. It depends on many things.
it can stop and if it stops you die. but you may not. yes it depends on a lot of things BUT if I tell people that they will not die and they do it will not be a good thing!!! but yes it all depends on things
@@AirConAcademy i didn't say you should write that you don't die. You could say: you can die. Because that's the truth
Perfect thank you!
Thank you!!! I am glad you enjoyed the video!!!
Wow that's an original idea for a shirt,kinda reminds me of an electrician from the UK😂😂😂😂
lol Thanks!!!!!
Thanks for thé vidéo
Thank yo for watching!!!
Its not a Megger, a Megger is a Trade Name that makes a insulation tester, that has arrange of mega ohms. Second point if a meter has a 9V battery does a insulation tester have a 500V battery.
My intention is not to confuse anyone so I'm using the term that they will be familiar with. Yes, some will have a 9 V battery in them, some. And I guess if you hook up enough batteries together you could have a 500 V battery. They are converting the nine volts to a higher voltage very similar to how they do it in a car. The car has a 12 V battery but they raise the voltage into the thousands for the spark-plugs to ignite the fuel. When I started doing this back in 1979 we used the Meggers that had a crank on them, in other words they had a mini generator inside. I hope this explains some of it to you. Thank you for your comment. Be careful out there and keep learning!
As an industrial electrician of 41 years we always called a megohmmeter or insulation tester a Megger for short.Hardly anybody ever called it a megohmmeter or insulation tester. Like you said Megger is just a trade name that makes insulation testers.
Perfect
Thank you so much! I appreciate your comment!
Thank you Sir 🙏
You are welcome I am glad you liked it!!!!
Thank you
Thank you I am glad you like it!!!
What's up Julio?!
HI!!! How is it going???
@@AirConAcademy U betrayed our class on AC #1 smh...
@@leonardozeledon6604 How did I do that????
@@AirConAcademy you aren't our instructor. U got the Tuesday guys 🧐
@@leonardozeledon6604 I am sorry for some reason I ended up doing Tuesday I wanted to do AC for you guys I am sorry!!!!
Superb
Thank you! I’m glad you liked it!
IEEE requires 1000+2x operating voltage
ohhh Thank you, and thank you for watching!!!
Kariar problem compressor coil cenection plz text koren
I'm sorry, I'm not sure I understand what you're asking.
Thanks sir
You're welcome! I'm glad you liked it!
👍🏼👍🏼👍🏼
Thank you!!!
Thanks bruce wayne!
Thank you!!!
I am not a robot
LOL Unfortunately I am not either! I hope you liked the video and thank you for sending the message.
I just pull the fuse and put a bolt its place, then hit the main and watch until I see smoke and flames...then I got the spot!
Ha ha ha! Yes! That will usually show you where the problem is. It is one of those one way troubleshooting ways and sometimes there is no coming back from there lol thanks a lot that was great! And thank you for watching!
thank you
Thank you, and thank you for watching!