Good video ! Yea, 100% !!! They are tight on cash / Ready to go out of Business !!! First You Have to Hound them to get paid. Then You Have a Few invoices with them that are overdue. Then all of a Sudden They are Gone or in Bankruptcy. Been there done that. Just Bid the Job at 4 Times the Regular Price & Tell them it's Cash Up front !!! or a Bank Check. They Will Get somebody else & You are Rid of a Headache you don't need. Be Firm !!! You don't need customers like that. Life is tooo Short ! Don't Let them make u feel guilty ! You did one For free already. They are Guilt trippers , People WILL take advantage of you if u let them !!! They WILL try to Guilt trip you again ! Get Rid of the Trash customers !!! Select Your Customers for a Better Quality of Life !!!
Ohms law ONLY applies to pure resistive loads. Compressor's motor is not pure resistive load, its a combination of resistive and reactive load. It is called impedance. Impedance is lowest when compressor doesn't run and get higher while compressor gets to speed. Impedance is highest when compressor run under designed load, that is why LRA (Locked Rotor Amps) during compressor start is as much as 8, 9 times higher that RLA (Rated Load Amps) after compressor got to designed RPM. Back EMF (Electromotive force) is a reason for all of that.
Thanks for this video, Curtis. This time I see what you are saying. Your ohm meter reading of 3 Meg Ohms, is just barely indicating damage inside the compressor windings insulation. It probably got an indirect hit from lightning. It leaves the motor mortally wounded. When the full 240 AC is applied it will arc across the damaged gap in the insulation to the case. Here's an analogy; There is no water leaking out of an empty bucket with a hole in the bottom but suddenly fill it with water and it is a different story. So both you and Georg Ohm are correct. Thanks for taking the time to produce this video Curtis. As for the deadbeat property management company make payment timing and a late fee part of the contract.
You are right, if you have a bad megohm reading it will intermittently trip a breaker or fuse ! When you megohm, you are introducing a current through the motor windings checking the varnish on the windings and infinity is best as the varnish breaks down to below a certain reading you will get nusense trips. I’ve done this many time on equipment up to 300 tons ( chillers ).
Curtis, I can't begin to guess how many times a week I say, "What gets rewarded, gets repeated." To quote The Lincoln Lawyer, "I don't get paid, I don't work." Love your videos and haven't missed one in years. Thanks for sharing.
I agree totally with what you said, but another thing I do is to run the unit with the compressor unplugged and if the breaker doesn't trip, then you have just ruled out any other short to ground possibility somewhere else in the condensing unit. Just another way to confirm it's a high resistance short to ground within the compressor causing the breaker to trip.
Worked on a few breaker trips for a large motor. 600volt and 400amp breaker. Found a lot of molten metal material in and around the breaker. Cleaned it up and used a megger not a DMM. Megger checked infinite ohms instead of 1 meg as initially test. Knew I was ok to recycle the breaker. Always used the high voltage megger as it's good practice but keep it away from electronic circuits.
Put a megger winding insulation tester on it. Sometimes windings break down partially (with some micro-distance away from a ground point) that cannot be read with an ohm meter using AA or 9V batteries. A megger insulation tester will induce 500V-5000V at mA current, will find all potential shorts in windings without damaging the windings. I know you know this as mentioned in video, just for those who don't.
Once you sense someone is taking advantage of you and you know you are a good person both in general and how you conduct business.....its time to walk away because they will try and bleed you dry. Keeping customers is important but some need to go. Well done Curtis.
Great Job! Definitely a bad Motor. I Worked 23 years In a Military Manufacturing facility …We had an overhead 480V 3 phase main buss line …feeding many disconnects to our equipment. One of the hanging (buss junctions) overhead shorted under load , shot sparks and kicked OFF One of the (Main 480V switch gears) at the plant on 3rd shift. Had a young…production supervisor, that wanted his CNC machines running making more parts . He wanted us to check the hanging buss junction overhead and we had: (16 M Ohms) to ground… on all 3 unloaded phases Production supervisor was very cocky with no electrical background at all! He Said, “We have to get our parts, we need to reset the Main switchgear… its just …16 M ohms That should be fine. We need to reset it to get the equipment going.” We all looked at him and said if you want to reset That Main 480V switchgear…go in there and pump the spring lever… and press the reset, turn it back on yourself. He called the maintenance supervisor About 3 AM in the morning and woke him up …Ticked Off at us ….Our Boss told him, do not turn that back on. That morning they called an electrical supply company …and we had to replace the bad section of the 480V buss. People just don’t understand, you never really want to see anything, checking to ground …other than (OL)!
Hey Curtis thanks for this kind of information, it is really important to understand how the business works, I believe your work ethic is very strong and your patience with customers is great, when I have hard times with clients always remember your behavior and makes me feel I can handle whatever discrepancy with respect, thanks again
It's flexing under the applied voltage from a slight short to a full short / with no voltage it relaxes back to the hire ohm / this why it fools you / it's burned out either way. Eye cut one compressor open and apart just to see what was going on)( a number of windings were very dark like shorted against each other . One culprit is the factory lead plug getting weak causing the amps to go hire on the other windings and burn it out.
A motor under load can leak to earth (ground) but test as clear when stationary and disconnected from the supply. Seen it plenty of times and even when tested at 1000 v on a meggar. There are huge magnetic forces in there when energised so the windings get stressed. You are so right 👍
I think there's an unanswered question: what is the resistance of the windings of the compressor? That's a different problem than the resistance of the windings to ground. Inside a compressor electric motor, the windings on the motor can short to themselves - lowering the resistance of the motor. Get the resistance low enough and the inrush current will be high enough to trip a breaker. What's the typical resistance of a compressor motor L1 to L2?
Like ur explanation of ohms law and why it trips breaker saw the nasty comments in past video either windings or leads inside compressor emmirsed in oil and bare somewhere any reading to ground unacceptable good man stand ur ground
I call that partially going to ground😎if you do do the job put in surge protector at disconnect ,the heavy incoming spikes is probably what took out both compressors
Sorry Curtis, I feel for you. not only is it hot hot and you got people challanging you in the comments about how you ohm out a compressor on top of it you got to deal with one of them freebee customers. eek. I'd be a little pissed off as well.. I learned from you on how to ohm out a compressor I use it all the time. works for me. keep it up I love your channel. it's one of my go too's after a hard day of HVACing.
Curtis how you doing buddy? I got to say I watched your video on freaking believable from 2 years ago and I just cracked up laughing you are hysterical. I like the letters you put on the screen run run run run run. Somebody's been dinking around in here... I love your sense of humor keep it up. You should have taken them beer cans could have bought yourself something to drink. Anyway I know you can't do that but this was one funny video. I've watched all your newer ones I do every time you put one out always like you keep up the good work. I noticed at your house you only have one heat pump? You should have one for each room what's wrong with you? Have a good day peace
Business has it's ups and downs, that one seems to be on the down side. I would give them that quote and go from there. If they use someone else, "bye". Thanks for sharing.
The other guys said it and I know it's easier said than done, but customers looking for freebies were never( retired now from the AZ sun ) my customers very long. Thanks for the videos!
Nothing worse than having to chase the money Curtis . If they tried to bugger you once they’ll do it time and time again. Best thing for you is to fire that client. I’ve fired several over the years and it feels good to have that anchor off your back. I even had one call me to come back and the deal was you pay in advance for the work or I don’t do it. It worked out well for me.👍👍🇨🇦
If the compressor instantly trips a properly sized breaker it could be shorted winging wiring + grounded winding + acidic oil contributing to lowering the resistance on the overheated and damaged spot of the motor winding. 3megaohem by itself will not trip the breaker instantly but it will lead to failure.
Hi Curtis. I wanted to tell you those Wago wire connectors you talked about a little while ago are now at Home Depot. If not there yet, you can get them at Amozon, too.
When I first graduated from HVAC school (way before your time), I would do free look sees at homes of aquaintances for experience. I did this one guy's house and found several problems, which I then told him about. He said, how about I go buy the parts and he would pay for them. I told him He would also have to pay me. He then said, I thought we were friends. I told him we weren't really friends, just that we knew each other. I never heard from him again, but I'm willing to bet he ended up paying more than I would have charged him. The moral of this story is, state up front how much you are willing to do for free before showing up. That gives you an out.
@@tripledo But I wasn't really doing business with him. I was doing him a favor by checking his A/C. Anything beyond that would be doing business, but he objected to that. He wanted me to spend hours fixing it for free. In a business situation, one gets paid.
You make a compelling argument. So in this case, the reason is that failing insulation resistance can be non-linear - at 9 volts it's 3 Meg, at 120 (volts to ground) it MIGHT be much lower. Trouble is, ... not always - but If it's tripping a breaker, it's probably failing. My theory of compressor insulation failure is that transient over-voltage (nearby lightning strikes that magnetically couple into power lines) sends kilovolts to the windings for a millisecond or so. Over time this repeats enough to arc internally and create carbon paths which at some point let 120 volts arc over.
Along with shorted windings, which would increase the inrush amperage, another possibility is a breaker going bad. Without an amp meter that can capture inrush, you'll never know whether it tripped because of a true overload or because the breaker is getting weak.
Do nothing for free and change them 10% more for slow payment. Every time you don’t get paid on time go up another 10%. My dear long departed granddad said that was the only way to handle those types people and he was not giving things away he had to pay for. He did give things and time away for friends and relatives but it stopped there. He had several good customers that you would have sworn see them were best friends, but they payed just as much as anyone maybe more sometime. 😁
All of my bids require a deposit to start work. If (and this has only happened once so far) I don't receive the second payment, my time and materials are paid. There is a reason you pay at the first window then receive the food at the second window.
Need a megger! It's a high-voltage ohm meter. I have one that I mostly use on motors. It can test ohms up to 1000V. Even with that specialized piece of test gear, I've had motors that the VFD says is bad, but it passes the megger. Nice explanation of what I would describe as a very complex problem!
A motor will pass a megger if it has a winding-to-winding short away from grounded stator plates. There's another tester that can analyze deviations causes by winding-only shorts. I have one called a 'Z' meter and it measures inductance/capacitance/micro-ohms, etc variations between the windings. But the megger will find 90% of problems.
@@sylkelster Excellent points! I figured most would get lost when diving into the mysteries of inductance. However, I do phase-to-phase and phase-to-ground checks and my 1KV megger catches 98% of those. But if the motor is ran from an inverter (VFD) without DVDT or sine wave filtering, the compromise could be in a higher voltage range than the megger tests at. This, I have encountered! The VFD says the motor is bad but the megger says it's ok. In that case, meter #3, an LCR meter! I believe that's what your using. If using and inverter, use 20KHz frequency range. Else, 120Hz is good. I like the megger, it puts an electrical stress on the conductors.
Your Skills are Not Worth wasting your Time, Energy and Aggravation. You have plenty of Respectful Customers who have NO Issues with Paying for your Services👍
Honest question. I'm reading a Copeland document on scroll compressors and they indicate that a reading as low as .5 Megaohm is acceptable on scroll compressors. How does this square with your experience on their products?
I also recall I believe reading Carrier doesn’t consider a compressor to be shorted to ground unless it reads 1K ohm to ground X line voltage. So a 240 volt compressor wouldn’t be considered grounded unless it reads 240K ohm or less to ground. Also moisture in the system can cause lower readings to ground. I’ve gotten into the practice of using high moisture driers on anything with POE oil. Years ago I used to do a lot of cell tower sites. They had 3-5 ton Bard or Marvair wall mount units. Back then they were all R-22 with Copeland scroll compressors 240 volt single phase. One time when replacing a compressor, after evacuating and putting virgin R-22 in the system but before running it, I decided to meg the compressor using the same Supco megger you have and it read bad. Started it up anyway and it ran just fine. So I started to check all of the compressors I was replacing in them. Same result. Don’t understand it but that’s just how it is. In fact I just recently replaced a small Copeland scroll in a 5 ton single phase York rooftop unit with 410A. Got the same result. When read with a standard ohmmeter, they usually read about 5 megaohms to ground. I think you may have something else going on there. Weak breaker or maybe the compressor is locked up. But I don’t blame you for not getting very involved if you have to hound them for payment. I’ve been doing commercial/industrial HVAC for about 33 years and I have to give you props for your professionalism and your thoroughness of your work. Something to be proud of. Keep up the good work. There’s a lot of hacks out there that give us all a bad name.
@@mikee2923 Danfoss states that: "The presence of refrigerant around the motor windings will result in lower resistance values to ground and higher leakage current readings. Such readings do not indicate a faulty compressor. To prevent this, the system can be first operated briefly to distribute refrigerant." They also claim that the readings above 1 Meg is fine...
That's the reason for checking with a megger, it uses a much higher voltage for testing for checking insulation breakdown. Most of the time, it won't breakdown at lower test voltages.
A circuit breaker is designed to trip when there is too much current flowing in the circuit. If the insulation in the circuit is allowing more current to flow than it's supposed to (or there is a partial short to ground) when power (240v) is applied then it will have a fault (that trips the breaker). That megameter comes in handy.
Working for free is kind & charitable, unfortunately, it doesn't pay the bills. Be careful in those hot attics. I actually got burned sitting on my light brown roof in 73 degrees after taking an Aleve for a headache.
Yup, I had a customer who informed me they no longer would pay net 30, it would be net 60. I adjusted my prices accordingly and they had the nerve to complain. I told them I had to recover the cost of the loan they were getting. The customer found someone else to screw and eventually paid me 120 days out. Not answering their calls was the best decision I ever made. 🙂
What do you think about a compressor that starts, runs, bangs and clangs and stops. Then in a few minutes it repeats the process? Not grounded out and not tripping breakers.
I've been an electrician for many years (many). I didn't once think that that couldn't trip a breaker. DC ohms is very different from inductance, and there's a capacitor involved. I did think that perhaps the breaker was bad however.
If it runs for a bit before it trips that means its tripping the overload mechanism not short not magnetic. A loose breaker connection will do same thing!!
20yrs in hvac and still currently am as a commercial tech. Ohms law really in my opinion doesn't matter here. Ohms law will tell you 240v @ 4.000 Mohms is essentially 0 amps which wouldn't be "enough to trip a breaker" which is why when you say that I believe it misleads people. The issue as another person stated is that it's the direct arc to ground due to the breakdown of the winding insulation that's "enough to trip a breaker". Yes, ohms law doesn't explain this because ohms law doesn't directly pertain to motors & windings. Ohms law just provides a general number when you input 2 known values which in this case is volts & resistance = current.
If you replaced that compressor 2 years ago, something REALLY bad is going on with that compressor setup. Either it is running with a VERY dirty coil, or running dirty filters all the time… Compressors don’t die… compressors are killed.
Hello Curtis, I'm with you on walking away from that customer. Also, be careful of customers that have their appliances insured. You'll be waiting a long time before the insurance company will pay you. 😉
While on auto, Once My ac in my apartment reach it's set temperature, it runs for a very long time before it shuts off. Do you know why this could be? I do leave it off while at work all day. When I come in, I turn it on and it takes a few hour to reach set temperature, but once it reaches it, it runs for like an hour or more longer, before shutting off.
Sure sounds like you’ve went way above and beyond to stay in the good graces of these folks! And now they don’t use you much but they want warranty on a free repair? Now I’m soft hearted but that’s ridiculous! Trying to ride that horse till the legs fall off ! Nope Nope Not gonna do it
This is non-linear behavior, in which resistance becomes a function of voltage applied. Usually an abrupt change. Perhaps you could use an old radio trick and apply line voltage with a couple of 60W light bulbs in series to limit current.
had a person back when I mowed lawns who I had to "chase down to get paid". they would literally leave home when I showed up at the two week schedule to mow their lawn. Then it would be me begging and pleading sometimes for as many as 3 yard cuttings to get paid. So finally one day when it was their time to get the grass cut, I simply didn't show! They called me a week later wanting to know where the "H" I was because they had company coming for a cook out and their yard looked awful. I told them from now on it was call for appointment and payment up front before I even unloaded a mower. They got pissed and hung up, needless to say nobody else would cut their grass because of their actions and to this day the place looks like a jungle!
I've never seen you so mad, I was just waiting for you to start throwing things and blaspheming, JK. Some customers, give them an inch they want to take a mile.
Yeah. The best test equipment can give you an erroneous result. No substitute for hands on experience. Should have let them reset the breaker on the unit until the compressor is truly fried.
Walk away! I worked for roto rooter cleaning drains in SW . They would dig a humongous hole so I could get to the drain cleanout, then they expected me to fill in the hole for free! I’ll pass!
