To get the upper motor bearing out, drill out the depressions around the outside of the case (there were holes which get welded from the outside). The winding core is pressed into the case The upper ring moves upward (from pressure coming through that small hole) to seal to the lid of the can. When the compressor stops, the ring moves down, relieving the pressure difference (preventing the scroll from running backwards from the pressure).
Very interesting Greg, I've never seen the insides of a scroll compressor till now. Lots of engineering went into that compressor. Thanks for showing us that!
That top seal is called a floating seal. It gets forced upwards into the muffler plate to allow the compressor to pump. If, during operation, pressure drops too low, often below around 30-40 psig, the floating seal will start clanking around since there isn't enough force to hold it into place anymore, and this can be heard from the outside with the unit fully running. It isn't really designed to spin and isn't really a pressure relief, although I guess you could maybe call it a negative pressure relief. Also that tubie thing on the top is a somewhat unnecessary check valve to prevent the compressor from running backwards during shutdown.
Cool video ! That top bit would be a pressure seal, when the compressor pumps it will pressurize that section and force it against the sealing surface on the bottom of the double wall top plate.
That must have been making some nasty noises for quite a while! The little copper valve in the head part of the scroll is to let discharge pressure back into the suction if the head pressure gets too high, just like in reciprocating compressors. They have a discharge check valve so start unloaded, you can hear the pressures equalise when the compressor stops in the characteristic growl as the scroll spin backwards. The big sealing thingy in the top scroll is subject to discharge pressure so acts as a kind of piston to push the two scrolls together so they seal, if a slug of oil gets into the scrolls it overcomes the pressure holding the scrolls together and the top one lifts up a bit to allow the oil to pass through, hence Copelands designation of compliant scroll. I have a few compressor autopsy vids too, in quite a few its the aluminium ring that failed.
I was in the trade for 12 years. And seen a lot of fails due to power spikes and drops on 3 phase . Train units are good . Well thier bigger stuff like 120 000 btu units . Biggest problem is usually lack of maintenance. LP slug back is the number one compressor killer that I have found .
+NZshooter shooter There are 2 other units on the roof. One twin to this unit and a Carrier. Both units were fine. We do the maintenance here so it's kept clean. One thing Trane didn't put in these units was a freeze stat. Customer turns A/C down to 60 degrees because as you know that makes it work faster and the coil turns into a glacier letting all that liquid refrigerant dump right back to mr. compressor.
Compressor starts slugging liquid and washes lubrication out of compressor, bearings fail and possibly causes shorted winding from metal shavings or overheats winding till it burns.
If I saw that type of upper bearing failure, I would be looking at a lubrication problem. Going by the serial date and video date, I would wonder if you should put on a crankcase heater to keep the refrigerant from migrating during the off cycle. But, that may be one of a number of factors that seem to point towards a lubrication problem with the upper rotor / crank bearing.
Who dreams these things up. That looks like something that would go on a space ship, or something NASA would engineer . Not a whole lot of serviceable parts or the access to. Great video, something new every day...Thanks...Ken
Greg, Thanks for the interesting explanation and demo of a scroll compressor. I think the windings of the motor are done to a nice golden black! The bearing damage reminds me of a ball bearing that freezes and that shaft starts turning in the inner bearing race. The shaft looks like it was turned on a lathe where it wore in the bearing. I bet there was all kinds of electrical nastiness going on when that motor finally blew! Thanks again for the video. I really enjoy these videos! They remind me of my days as a service tech and all the crap you had to deal with. "The machine was running fine until this part fell out." or "It started making this sound like grinding gears." Idiots! Have a good one! Dave
Greg, it looks to me as if that "groove" is actually part of the casting on that small piece that you said had worn a groove into itself. In the video, you took your finger and pulled out what looked like brass "goop" from that groove. To me, it looks like that section was once filled with grease, and it looks like it's some sort of grease feeder for the bearing surface. For example, if you have a bearing surface that you want to keep lubricated, 90% of that bearing surface could be the bearing, and the other 10% could be a special port with packed grease inside to keep the bearing surface lubricated. I could be completely wrong, of course, as I have never seen the inside of one of these compressors, and I have no clue how they function internally. It just seemed logical given the fact that it looks to be part of the casting, and you pulled out a grease like substance from that particular groove. I think the brass "goop" might have been grease with particles of brass packed into it. Just a thought. Nice video!
Had a homerowner file a claim on her insurance for a burnt compressor.Insurance company sent a technician to do an autopsy on the compressor. He did it out of his van at our shop. I watch him and he did exactly what you just did. He found the internal overload shoted out.He said a lot of his jobs there is nothing wrong with the compressors.
Very informative video! you should make more of this type of videos. Very interesting to see how ingenious are this compressor made. Also the failure of the bearing is impressive. Why did it failed?? Didn't looked like lack of lubrication.
+Steve Paxon After doing the knuckle buster treatment so many times they get cut out and new ones go in. Looks better and takes less time for me to cut them out and put new ones in than try to fight with it.
no. It's called a "floating seal". Its job is to get forced upwards against the muffler plate and to fall back down if pressure drops too low to prevent the compressor from running into a vacuum.
I have 2 in my shop right now, identical zp67 compressors. One was a bad burn out, the other is a bad orbital bearing and sleeve. Wush i could just get internal parts and repair these damn things
Wonder why compressor circuits don’t use a thermal trip built into the contactor like direct-on-line motor starters (but with a latched cutout). It won’t save the compressor if the bearings go bad, but it’ll save the windings cooking and contaminating the refrigeration circuit.
I've seen amperage monitoring by an onboard computer on much larger systems and on a few inverter driven compressors we have in a couple experimental units. Usually it comes down to price. This is only a 5 ton unit. You can build a ton of safeties into the unit to account for almost every possibility, but if you have to then sell that unit at 10-15k more than a competitor then who is going to buy it. There is an internal thermal overload that is technically supposed to prevent this from happening, but it's an automatic reset.
It runs between 2600 rpm and 3000 rpm. On old R22 refrigerant you will have HP ( discharge )240 psi LP (suction ) of 60 psi It's nice to see a nother frigy on RU-vid ☺
Hi Greg. Loved the forensic examination. Always interesting to find the failure mode. While watching the video something kept bothering me - that split bearing shows wear all around it yet the lobes of the rotor casting are in the way to get that kind of wear pattern. Was that bearing originally pressed into the bit you had to drill out of the casing? Also, the bit you are holding at 24:00 looks like an eccentric maybe acting as an oil pressure booster to force oil through the split in the bearing? That would help explain the chain of events. Looking the the specimen you so kindly provided, more important than not pumping freon in reverse rotation is the fact that no oil lubrication can take place at all. Scrolls appear to be highly rotation sensitive. Possibly during the install or later during some electrical work, someone ran the compressor backward a bit too long starting the wear. Particles build up in the slit starving the bearing and increasing oil pressure above it. The boss/housing heats up and expands enough that it loses grip on the bearing and oil pressure forces the bearing further down the rotor shaft leaving a much smaller bearing surface to ride on. The reduced bearing allows oscillation of the shaft which accelerates wear. Sounds plausible and leads me to wonder why the space is there for the bearing to drop into in the first place. You'd think there would be a hard stop to keep that from happening. Maybe I'm not seeing everything and have it all wrong but it's fun to speculate :P
I have 5 year old 2.5 ton Emerson scroll that knocked for 10 seconds 3 minutes after start up? Yesterday it didn’t start till I killed power and unplugged the external compacitor .Then it didn’t recycle till I did that again. It’s been cycling all day today but why the knocking? Excellent video.
It could possibly be bad oil return. If the unit hasn't started in a long time (all winter season) there is a possibility for the compressor to be somewhat noisy for the first few minutes of running until the oil starts to circulate through the system. This is especially apparent on units with the air handler lower than the condensing unit. Oil will migrate to the lowest warmest spot.
After seeing your vid seen an Australia guy power one up with the top off.Was very cool and informative.However you got to the guts to the bottom.5 gold stars to you sir.
The piece with the multiple holes / indents sen at time 30:22, could that be used as a balance weight or "harmonic balance" to keep the rotary-to-sliding action from tearing things apart ?
Dear i hve an issue with my compressor, during operation compressor not taking any amps but its making heavy noise wat might be the issue , this is happen twice in a month and hve replaced 2 compressor due to this but unable to get to the root cause. Plz held answer to my question.
Was that a pressure relief to compensate for a lack of an overload switch? Not sure if any scroll compressors have any type of overload switch is why I am asking.
Great video! So I've read that scrolls should not be run in a vacuum. And that the biggest issue of running in vacuum is the increased risk of arcing within the compressor due to much tighter tolerance. Can someone explain where would this arcing be occuring? Is the arcing between the windings which I would presume would lead to shorts. Just curious what is the tighter tolerance? Less insulation around each winding??? Thanks for the info!
@Preston Murphy maybe I should rephrase the question.. can you run a scroll compressor to pump a units refrigerant back into the condenser without damaging the compressor? Can you draw the suction line right down to 0 and shut it off without damage to the scroll compressor? But at any rate I'm curious where this arcing occurs that I've read about. If ya don't know that's ok
KELLY ANDERSON; The problem with any compressor running in a vacuum is that there is low, or no flow. This can cause several problems. In the scroll unit, the vanes in the bottom of the shaft- the metal ones IN the shaft- can't pump the oil effectively. The refrigerant is drawn in and takes oil with it. Lack of lubrication is the mode of failure for the majority of these compressors. The plastic part at the bottom of the shaft that was broken off while removing the shaft doesn't pump the oil. It is an oil agitator. It's purpose is to stir up the oil to prevent the refrigerant from getting absorbed by the oil, which makes it pretty much useless. • If you use the compressor to pump down just one time for service, ie: replacing an expansion valve, you're not going to hurt it. Just keep the run time as short as you can. Remember, oil travels with the refrigerant and sprays all over everything inside the compressor when it gets to the compressor. • One more thing to note is that the refrigerant on medium and high temperature systems is what cools the motor. The easiest way to overheat the windings is to run short on refrigerant!! No flow means no cooling!! Poor flow means poor cooling. Just as humans are air cooled, they need refrigerant flowing to cool the windings. • Think about this experiment: Put a human into a small insulated box that is air tight with only a way to breathe provided by some sort of tubes etc. Cause of death? Hyperthermia. You will 'easy bake' to death. • So does the motor in a sealed compressor with no other means to cool itself. • Keep scroll compressor'd systems fully charged!! Overcharging can cause damage in any system of course! In a scroll, the liquid floodback causes one-sided wear as the liquid places excess pressure on the opposite side from the intake. That's what it looks like happened on this unit. Plugged up air filters, dirty coils, running in low ambient, are usually the culprits. "Compliant" just means that the compressor will tolerate floodback for extended times, but that doesn't mean that it SHOULD be run flooding back indefinitely!! •••••Great video though!! BTW: The large seal assembly is so that the compressor can be assembled blindly at the factory. You'd have a tough time lining it all up for the final weld without it! The Matsushita scroll has the outlet line through the side of the case and eliminates this component. The internal blow off is attached to that outlet line in the uppermost casting.
@@johninmilford7719 thank you so much for all that info!!! I will be going back a rereading this again to make some notes!! But your info cleared up much of my questions!!!
Not trying to be an armchair mechanic or put you down in any way.. I've been in HVAC&R for 33yrs. You did check your contactor for that compressor? That looks more like a power problem than bearing fail Or even moisture causing an acidic environment , breaking down the winding insulation. Especially if it is not seized up. I have seen a lot of Techs fail to check the contacts. I've seen legs of contactor almost melted away yet compressor runs. If that had been in a rack system I would be checking the oil system . If too hot that will definitely wreak havoc on your bearings and even cause catastrophic failure in recips. Plus what other commenters said about flood back. We use the scrolls in wanna be supermarket applications in Canada. That top bear has been a notorious problem for the first gen of scrolls. They do make a lot of noise and vibration. So bad that the Manufactures would have a belly band around compressor to stop pipe vibration.(Hussmann. Protocall) After change out vibration was gone and I saw the same bearing wear as yours. Like your vids. Oh how do you like the smell of that chooched oil ? pretty bad eh!
+C Thompson Oh yeah burnt oil is tasty stuff. This was in a 5 ton package unit with no previous leaks. It was actually siezed. I had to remove the bronze bearing ring to be able to turn it by hand. It would turn and lock in the same spot no matter the rotation. I always check contactors on compressor changes. When in doubt it gets changed. Small price to pay to protect the most expensive part in the system.
It is internally thermally protected, but if it was locked rotor all I would have done is heat up until it tripped, cool down, and start the process all over again until it finally popped.
Thanks for the great video!Quick question, with a massive burnout like this and all that char and blackoil inside, would this also spread to parts like any installed Sight Glasses in such a way as to get visual confirmation before yanking out the compressor?
Hi Greg, Thanks for showing the inner workings of the scroll compressor. Do these tend to last longer since there are fewer moving parts? I hope that you are going to recycle those copper windings! You get a lot of wire from a motor like that! Can you explain the relationship between BTU's and tons? Window AC units are always rated in BTU's while larger commercial units are rated in tons. This has always confused me. How do you know how many tons you need? Thanks! -mike
They are quieter and more energy efficient. In my experience they're a bit more temperamental with oil return and don't tolerate oil loss (due to leak) as much as a regular reciprocating. 12,000 BTU's = 1 Ton of capacity. Most window units for 115v go up to 1 ton anything over is 230v. Tonnage requirements are based for window units on room room square footage. A central a/c system would also include things like average outdoor temp, # of windows, insulation thickness and type, exposure of house among other things. A commercial building will also take into account occupancy and I. the case of a restaurant, kitchen equipment. There are a LOT of shortcuts and fudge factors here. Basically too small a system and it won't get cool enough. Too large a system and it won't run long enough to remove the moisture from the air and you get that cold clamy feeling.
Dude you are awesome !!!!! What a cool excursion into a scroll!! Most awesome!!!! Totally!!!! Thanks for Your Time!!! That's Friggin Cool!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Actually it's a 3 phase compressor so no starting components. If you look there are no wires and no provisions for wires to be connected to the plastic.piece nor inside the sump where it was sitting .
+Halligan142 same same, I wanted to see what was behind the black screws and springs and brushes flew everywhere. Couldn't find the second brush so I put it back together with the spring touching the armature. He knew exactly who to beat on when his drill looked like the 4th of July...lol
Hi mate. That thing was set up to fail. Who puts bush bearings on a high revving motor? It's like putting bush bearings on your car wheels. These sort of things should be criminal. Now the whole cooling system is contaminated, and won't be able to be cleaned, to the level that you can say that all has been removed. A new TX valve and new receiver dryer, it's criminal. And all so that the manufacturer can sell more compressors. How did you get the crud out of that system???? If not completely clean, the system is set up to fail soon. I would hate to be you on this job.......
The unit has fixed orifice metering devices. We used Rx-11 flush to flush out the system and installed a new liquid and a suction line filter dryer. We also made sure all the pressure controls were working correctly. We got it running and they'll only be using the A/C in the unit for the next month or so until the cold sets in. In the spring we will go back change the dryers again and perform another flush if necessary.
Sleeve bearing perform well in situations such as inside a compressor because there is a constant spray of oil to keep the metal from ever touching the mating surface. That's the case in many reciprocating compressors too! •••The caveat is that if you run short, over charge, or do anything else to change the way that oil flows to said bearing, you're asking for trouble. (Your car's wheels don't have means to constantly and reliably lubricate their bearings, so, you're right, that would be a poor choice. Bad comparison there. •In ANY bearing the main goal of the lubrication is so that the mating parts, don't "mate" at all! There will be a film of lubricant between them.
At 8:00 he said it doesn't rotate it "wobbles it doesn't rotate." Well it does rotate it just doesn't do it symmetrically it does it asymmetrically. It rotates on an elliptical axis. I guess I shouldn't expect much from a technician.
