Milwaukee Cordless Fan - Weird fault - Can I fix it?
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- čas přidán 27. 08. 2024
- In this video we are going to be taking a look at a Milwaukee Cordless fan. It has a weird fault as it works fine on speed settings 1 and 2, but shuts off on speed 3.
It does this on both the mains adapter and when using a M18 battery.
Let's take it apart, see how it works, and hopefully repair it!
Update 1:
Someone sent me a picture of the fan motor
imgur.com/a/DN...
It seems to be 18v 20w, so that would mean 20w / 18v = 1.111A ??
The power supply provided is marked 2.5a.
There is an internal fuse inside the fan, which looks original and isn't blown.
Are they putting too much load on the fan? as if it's drawing 2.6A at full power that would be 46w if I'm right.
I'm not 100% if the calculation works exactly like that with it being an inductive load.
Please feel free to correct me if I'm wrong! (I'm not an expert and just repair stuff as a hobby).
Update 2:
I've since tried running the motor at full speed by adjusting the current sense circuit (you could just wire the fan direct to the power) but the motor seems to overheat after an hour and a thermal cut out on the motor kicks in, so either the motor is damaged but the unit seems relatively new and has had little use, or they are putting too much strain / load on the motor as I've seem a few of these on eBay with the exact same fault
#electronics #electronicscreators #electronicsrepair
Milwaukee Cordless Fan Repair
Milwaukee Fan Problem
M18 Fan Fault
Milwaukee M18 Fan not working
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M18 Fan Problem
M18 Cordless Fan Fault
When I was running AFREP in the USAF and training for micro/ micro-miniature electronics repair. The instructor told us about 80% of the repairs we would do would be from design errors or previous "repairs"! If anything, he was off even at 80%, it was a LOT more. I could not believe the number of engineering design faults I had to re-engineer to be correct. After retiring from the USA F and taking a job with Northrop-Grumman I got to see even MORE design faults by "trained" engineers! Again, I had to figure out what was wrong, find their error, send them a message that, once again, you made a mistake. I started signing my emails as "Quality Engineer" as I had to SO often notify them of a design error. Truly frustrating! Excellent repair were you also see an engineer made and error.
Thanks for that 👍 Did you see the Philips sound bar video I did? A guy bought 25 of them all with the same fault and sent me one to look at... he said there was a shipping container filled with them all with the same fault.
Mine is faulty on all three speeds. I thought it was a dirty switch at first because if i were to rapidly turn the knob through the different speeds, it seemed to work for a little while before eventually shutting off. I haven't opened it up yet but this gives me some additional points to test out. Thanks for posting.
Hopefully yo manage to get it sorted 👍
TLDR: tight or dried out bushings might be giving you that extra resistance
I have spend a good bit of my life taking domestic extractor fans apart when they fail and getting them going again. I have posted a few videos of this. They usually fail from a mechanical point of view, lubrication of the bushings, I have a few units at different locations that I run constantly in damp environments, not sure the damp matters but the bearings always dry up. It is very easy to disassemble, depending on brand, and clean and lubricate. In your case, if you could figure out where to do it, a shot of WD or some other penetrator might loosen the lube enough to reduce the resistance on that fan on the high setting, but to test it I guess you would have to go back to the original resistor. Or just take the motor apart and clean the shaft and inside the bushing. It is a guess, most of the ones I have dealt with were shaded pole induction motors, very weak, all similar bushings. I haven't been inside many dc fans. I'm waffling, tight or dried out bushings might be giving you that extra resistance.
Thanks bootsowen. I don't think that's the case here. The fan spins nice and free and the unit is fairly new. There's also a lot of units with the same fault on Ebay. I honestly think they've used a motor that's not really up to the job, or put too big a fan on it.
Hi, I was also thinking of bearings/bushings. Because, it sounds like a jet engine than a quiet fan. (Maybe hearing through the mic and my speakers)
@@BuyitFixitI’ve had this fan through heavy use, abuse and an uncle cleaning it with brake cleaner for 6 years. Not a weak motor
I really enjoyed the fault finding on that one along with the use of the scope and explaining the circuit. I think quite possibly my favourite video of yours to date 👍
Glad you enjoyed it Vince and thank you for watching 👍👌👌
This reminds me of the 200 HP new air compressor that I was troubleshooting. I worked as a tech support engineer for the largest air compressor company in the US. This compressor kept tripping the cooling fan motor OL relay. We discovered that the fan blades were pitched wrong causing long term high current to trip the relay. The fans were plastic and set into a fan hub that could not be reset. We replaced the fan and solved the problem. When you run at the ragged edge of the spec that is what can happen.
Interesting. Thank you for commenting 👍
My favorite fix of the series by far... by now I am following you along and getting there just after you, lol. On this one, it was more of what I see on a daily basis in my job. I would definitely be looking at overcurrent issues, be it mechanical or electronic. The idea of the resistor change I got there about 5 seconds before you, so that made me happy 😂. Using the bench power supply to check the current was brill, then the ammeter was spot on. I would be looking at the mechanicals first as the design probably was ok if they have made 1000's of these with most of them working ok. Maybe a damaged blade, poorly seated bearing, failing bearing, anything like this creating a bit more resistance and causing the amperage to go up too much. After that, I would check the resistors on the board or anything that provides a resistance as it could be faulty and allowing more current through than normal. By changing the resistor for a higher value, it does prove that something is weak and allowing more amperage to be pulled through and it then tripping out on OC. I loved the fix by the way, very apt Mick, I liked it. Coming to the end of the milwaukee playlist now, loving the series, keep the great stuff coming 👍👌👏👏👏
Thanks mate, I haven't done a Milwaukee repairs for a little while but I've got a few new items to have a look at 🙂👍
Your knowledge is incredible,i fix computers and laptops !but never go that deep, i still stop stuff going in to landfill ! as best as i can ! You Sir are way better at fixing things than i could !
Thanks Mike. I'm no expert.. I've just always been interested in computers and electronics and love to know how things work, and I like learning about stuff 🙂
What impresses me the most is how you identify components and their role in the circuit. Is it a skill you develope or have you been taught? Btw complete noob on fixing things here.
I've just repaired stuff for years, you get to know what parts do or what parts of a circuit normally look like. Now we have the internet it's a lot easier to search numbers on ICs and components to see what they do or find datasheets.
Thanks for explaining the circuit. It was nice to see chips that I have heard of, the 555 time I even used at school in electronics GCSE a long time ago. It was good to see that classic chip being used. If you do not know what the problem was I sure don't.
I think either a design problem (too much load on that motor) or a bad batch of motors possibly.
Excellent video as usual. I learnt lot from your videos. Much appreciated.
You're welcome bob 👍 Thanks for the feedback and glad you got something out of it!
As there are a lot on ebay with the same fault it looks like a problem in the current sense circuit. Could be a bit sensitive and tolerance on the componet values mean most are ok but a significant propotion show this fault. Would need to reverse engineer the circuit and then play with values. Your solution is much easier, nice one.
Thanks Bike Forever. I did try adjusting the current circuit and got the motor to drive at full. However it overheats after about an hour and thermal cutout trips. I updated the video description with some further details 👍
@@BuyitFixit I think it is a dirty commutator in the motor.
@@paulstaf These were pretty much brand new units, no dirt or dust on the blades or casing...
Which would lead one to believe this is a bad design...especially with the data point of the current sensing circuit mod with corresponding overheat. Either beef up the control circuit or get a more suitable motor/fan combo. 2.5Amps doesn't sound like that gawd awful of a load for a fan though, so they shouldn't skimp on the control components and PD components@@BuyitFixit
@@BuyitFixit Are you sure that the shutdown of the electric motor occurred when overheating was detected?
Is there a system in place to detect motor overheating?
I also own this fan. I have the same problem. Using it in first gear it also shuts down after an hour. I think there is a built-in timer that measures the time from startup and turns off the fan after 60 minutes.
Another great fault find, best part is you always explain what everything is or does. Maybe Milwaukee are pushing the limits too far but would this not be revealed with the testing, seeing as it cuts off almost immediately, mains or battery.
Thanks 👍
I used to Work on scanners, printers, daisy wheel printers, impact printers etc Found bronze bearings put extra load on motors when they dried up! Service manuals all said do not oil these bearings just clean them! Oil mixed with paper dust etc would wear the bearings out! It was a nightmare! Laser printers didn’t give any of this trouble ! 😊
I've bought 3 of these exact fans the first two were early versions that did the same exact thing but on all three speeds. The newer ones work great now. Haven't looked inside for changes but I think they fixed or changed something to correct it. The newer one I have now runs 8-10 hours a day, every day now with no problems.
Thanks for that info 👍. I guess it must have been a design problem then. I wonder what they have changed. Does it blow as much air as the early versions?
@@BuyitFixit The first two were faulty right out of the box new. So I couldn't compare the two to the newest one as far as airflow.
@@MiniDigging Ah ok. I had just been thinking if they had just done something similar to what I did and reduce the output slightly.
@@BuyitFixit Not sure, but it was probably something else I would think as they spun very freely and it still done that on all three speeds with mine. Maybe something other than current limiting alone. IDK.
@@MiniDigging Thanks mini digging 👍
A fan of a Milwaukee fan. 😁 I do not have any Milwaukee tools but I do like the look of them. I had considered getting a impact driver a few years back as was doing some restoration work on my classic style VW Beetle that I imported from Mexico in the 90's.
I've got an impact gun for sockets and an impact driver. I love the impact driver it's one of the tools I use most often m18 version.
Don't tell me you fixed both of them. 😄@@BuyitFixit
No, I had these before I started repairing Milwaukee stuff 😂😂😂
Quite the Milwaukee FAN lol nice little pun, I think it all comes down to poor design, and throwing it what they had lying about, I think the motor isn't up to the challenge and they are pushing it to the limit, but thanks for a great video really enjoying them all, have a great weekend
Thanks Morten. Hope you have a great weekend too!
Goddamn, a fan that costs that much and they can't be bothered with engineering or parts checking?
You get that "dedication" when certain brands get "big" enough.
Look at the capacity of Energizer and Duracell rechargeable batteries compared to the competition (smaller brands) and you see how paying more money for a recognized brand can (sometimes) get you less.
It's like the Energizer and Duracell flashlights: mass produced, flimsy, low light output, and costs more. Not that I'd buy one of their lights, but some people who don't read specifications (or don't understand them) would think it's a good product due to the name.
Thought I'd comment my findings on a recently purchased ebay listing. Annoyingly someone else had been in there, done the 10k resistor replacement, the motor was smoking whilst being powered with 18v from bench supply, fuse was gone (3amp F2). The motor had resistance whilst being turned without the fan attached. Used an angle grinder to remove the bent over motor tabs, removed brush assembly, spun the shaft up with a drill and cleaned commutator bars with scotchbrite then scraped the gaps with a knife then fine wire brush, the back bearing got a bit of silicone grease on it, turned lovely after that. Motor controlling mosfet was shorted so even in the off position it was turning. Not wanting to miss out on the full power i replaced the 10k with a 220r resistor. Thought it was fixed then discovered a loss in continuity on the positive wire going to the motor.
Pretty sure I didn't see a fan inside the motor so might contribute to the overheating. I decided to drill 4mm holes around the motor mounting plate so hopefully some air gets drawn through past the motor. If i do come across any overheating i might look into a heatsink or maybe change the motor.
Thanks for the info 👍
That looks like the fan blade pitch as they trying to move too move much air with that little fan and the wind resistance is causing the fan motor to draw too much current. You could have removed the fan from the motor and run the bare motor to test. I am really enjoy watching your videos 😊.
Thanks 👍I did try powering the motor directly and it ran at full power, after about an hour the motor overheated and the thermal cut out tripped.
That was interesting how you decided it was a resistor. I was going down a different path to come up with a solution on the problem, although my solution probably wasn't right anyway. I thought the timer IC was faulty by the looks of the scope when it cut out on the high. It seemed like the IC didn't like the voltage and that was why it shut off, but that was just the lines of how I was thinking about it. Awesome fix by the way. I'm working on a vizio tv at the moment, and this thing has me stumped..Oh, and it one of the only models you can't get schematics for. lol
Thanks Ron. The fix I did still isn't quite right. I think the motors are either faulty or the pitch on the blades is wrong. I did try bypassing the current limiting and it ran at full power for around an hour then the motor thermal cut out kicked in as it was mad hot. So my solution works just at slightly reduced speed. Good luck with your visio 👍
It's the underated dioide and the fuse is blown. Also, Black brown Black silver brown color code gives you a 0.1ohm resistor. Your resistor is not the problem unless you assume it should be a 1-ohm resistor. @@BuyitFixit Here is the fix " Milwaukee jobsite fan m18. bug fixes." - Nelson Matias
Perhaps the first test after observing the fan motor cutout would be to inspect the circuit PCB with a thermal camera to see if there are any hot spots. Although the PCB did not look overheated on the top side. If the control board is not cutting out, then it must be the motor thermal breaker. The thermal breaker seems to be the automatic resetting type. If so, there is potentially an even quicker way to diagnose the fan if you can get a freeze spray nozzle directly on the thermal breaker. You may be able to access it through the fan vents. If so, you can just freeze down the thermal breaker and the fan motor should start working again. This would verify the problem. Not sure what the fix would be other than replacing the fan motor.
Thanks👍I did do a lot more tests than were in the video, including adjusting then current limiting. This did work at full power, but after around 3 hours the motor overheated and cut out and was very hot. This was pretty much a brand new unit and the guy had quite a few listed in same condition. I think it could have been a bad batch of motors? Either that or they are just asking too much of the motor.
I think I'd replace the speed 1 and 2 resistors as well to form a larger separation in speeds. Maybe get an anemometer and measure the airspeed at each speed... really geek out on the fix!
😂😂😂😂
Shunt resistor is 0.1 ohm and you measured 2.8A current in mode 3. So the motor draws too much current. Dry bearings maybe
Yes the motor is definitely drawing too much current. The fan was pretty much brand new, and the blades turned nice and smooth. I did change a resistor on the current sense circuit and it ran on full power for about 3 hours before the motor overheated and a thermal cutout kicked in, which is why I think they were driving it too hard or a faulty batch of motors?
I would personnaly say that it is a mechanical problem. With everything brand new the fan works the very best. It is surely a mechanical condition that happens and changes the load on the motor. They have made quite a few of those fan and it is a cash cow for the company.
It's odd as the seller had a few for sale with the same problem, all were pretty much in as new condition.
If I remember correctly, the 555 timing is set by an RC combination. It could be a capacitor faulty or drifted out of spec to make the duty cycle too high.
Possibly but these were pretty much brand new units and there was a few listed with the same fault. I think bad batch of motors or too much load on the motor as even powering the motor directly caused it to overheat after about an hour of operation.
I did not finish the video yet but the thing caught my mind is that stepping down from speed III it doesn't work till the power is cut on 0 then running again.
Hmm strange, I can't remember if the one I have here does that.
Looks like you have a popped joint on the left hand side of the current sense resistor. If the joint has some resistance then the circuit will think that more current is being drawn than there actually is.
I did try to bypass the current sensing, which made the unit run at full speed, however the motor got very hot and cut out after about an hour due to a thermal cut out on the motor. It's almost like the motor has too much load on it, or the motor slightly faulty. The unit is almost brand new, and at the time there was quite a few listed with exactly the same fault so perhaps they had a bad batch of motors or they changed the fan blade pitch or something?
Great video! Thank you.
Thanks 👍
I enjoy the channel, thanks.
For God's sake, it is a fan. Why does it have integrated circuits and PWM control? It should have a switch and a few resistors. This over-complication of things is getting silly.
Thanks 👍I think they used PWM to save energy as this is designed to run from a battery. Using resistors would be less efficient as a lot of energy would be dissipated as heat.
I'd be swapping that shunt resistor for another one, or just disconnect it from the comparator input and tie that low so you can at least run it at full speed for a while to make sure it's ok, not warming the battery or making smells etc
Not on the video, but I did try changing one of the resistors on the comparator circuit to allow more current. The motor ran for about 1hr then overheats and a thermal trip cuts in. I updated the video description with a picture of the motor and some stuff I tried.
@@BuyitFixit ahh I see! Just read all that now :) I do wish YT made it easier to see the description on the mobile interface. One last suggestion now you've proven it's the motor (if it's not yet ruined) - try puffing some graphite dust in there :)
Is that for lubrication? It seems to rotate quite freely. Personally I think they have too much load on the motors and its causing them to fail or partially fail. Theres a fair few of these fans I've seen on Ebay and all relatively new, with the same issue.
@@BuyitFixit Ok. Yes it was for lubrication. Oh that's a shame if you're right then. Maybe the 555 config could be tweaked to generate 33/66/75% PWM instead but not worth the effort when you can just run it on mode 2 I guess. Thanks for the entertainment anyway; I enjoy the videos :)
@@pete3897 Thanks Pete 👍👍
Seeing how their stuff is built, are you still a Milwaukee fan?
😂😂😂😂 some of their stuff is good, some not so good. I've got the impact driver and a couple of grinders which I use regularly and they are great 🙂
Or it could just be that component tolerances were making the cut-out too sensitive. I would have stuck a 1 ohm 0.25 watt resistor across the 0.1 ohm sense resistor in the hope that it would reduce the voltage (for 2.5a load) enough to allow the full 2.5a to flow without tripping the LM324 circuit.
I actually tried powering the motor directly, and it overheated after about 2 hours with the thermal cutout on the rear of it. Full speed does the exact same thing (100% duty cycle) but shuts off as it senses it's drawing more current that it should be.
The resistor is 0.1 ohm. That is brown blk blk silver. The silver band is divide by 10 or 0.1 times.
Thanks👍 I just looked back at the video and it is indeed a 0.1 Ohm. It looks black, brown, black, silver, brown (possibly). Thanks for pointing it out. You seem to be the only person that has noticed! I'm no expert and still make mistakes 😂👍
A really interesting video; thanks. I'm a bit late to the party here, and maybe I missed something but here goes....As you say, the op amp seems to be being used as a comparator (if so, straight away it seems odd that they don't use a purpose built compatator such as the LM2901N). Did you mention where the reference voltage comes from (I may have missed it) and what that reference voltage is?
Thanks 👍 From what I remember the ref voltage comes in around the right hand side bottom of the chip (on the video)..Theres two resistors that form a resistive divider. I did change one of them and the fan run at full speed for about an hour but then the motor overheat and the thermal fuse kicks in on the back of the motor..I can't remember the ref voltage off hand. Hope that helps.
Maybe they designed the current sense with a low tolerance resistor value and then the resistor got changed in production to a high tolerance value (cheaper). Then the over protection kicks on or something. Just a guess. or maybe not since the volt and amps seems to hand in hand value wise... Anyway, you could have swopped the motor out for a resistor load of similar amp value and see if the board shuts down at that current value to see if it is the motor or the board.
I tried powering the motor directly (same as 100% duty cycle on the pwm) after an hour it was too hot to touch and thermal cut out kicked in. I think it's a bad batch of motors or the motor can't cope with the load on it.
Awesome, did you ever find a satisfactory reason for this fault ? you mentioned more on ebay with the same fault anything come from that ?
But whatever, a great solution and more economic to run! not quite the "Breeze" more 'gusty' !!....cheers.
Cheers Andymouse 👍No never did find the exact reason, bad batch of motors? asking too much of it? Yes seems odd that there were a number of these with the same fault for sale at the time...
Great video as usual looks like black burn marks on black wire going to pcb ?
Thanks Wayne, not sure if I caught that with my hot air station.
What was the current rating of the power supply brick? Could be a good indication of the expected maximum load..
Sorry for the late reply, I had to find the thing. 18v 2.5A
It's just a guess, but the inner parts of the fan may be slightly jammed by something, so the fan isn't running as free as it should
I did try turning it by hand and it was fine, also there was multiple of these all in new condition, advertised around the same time with the same problem.
@@BuyitFixit the specs of the supplied fans can vary and change over time. Maybe this fan was just inside of the specs during the quality control, but after some time it's current draw has slightly increased
Could well be the case.
Good temporary workaround, though the motor sounds 'rumbly' (bearings perhaps) and it may be worth checking the spec (assuming the motor has anything written on it). All the Milwaukee products you obtain look like new, which is worrying in itself and may point to poor design.
Motor seems quite smooth, someone did send me a picture of one with the number on. D2825FS-B 18v DC 20W is what it says, so working on 20w / 18v = 1.111amps and it seems to be drawing double that. But if the motor is only 20w why supply a 2.5a power supply? Unless they are over driving the motor?
@@BuyitFixit Bizarre, may be worth disconnecting the motor and powering it direct from your PSU to check current 'under load' (but then you may need another to compare it with). Thoughts of designers thinking 'let's see what happens if we drive this using pretend PWM, then, oops'.
I've just updated the video description with the picture and other info.
@@BuyitFixit Ah, yes, 2oW rated power. Then jam a honking great lump of plastic on it, put it in a cage and expect it to force air. At some later date worth comparing with another one (suspect motor is under-rated but may be wrong). I'm sure you have better things to do.
Is the shaft in contact with the case anywhere causing friction
Great workaround fix though 😊
It's hard to see the color code on that shunt resistor, but it sure doesn't look like orange-black-gold or red-yellow-gold. (0.3 or 0.27 ohms). It *looks* like black-brown-black, which would be a screwy way of saying 0.1 ohms? (And would make more sense for a shunt than 1 ohm.) If so, then the shunt is bad and at least three times too high, which would explain the bogus trip at 3.
Edit: Putting the fan face-down on the bench might restrict the air flow enough to raise the amps. What's the bench supply measuring with fan in normal upright position? Perhaps they spec'd the wall wart and current limit with very little margin, and at speed 3 it normally draws something like 2.4 amps.
Thanks Michael. The colour code was black brown black silver. Someone sent me a picture of the motor in their fan, I put it in the video description. It's an 18v 20w motor. I did try adjusting the current limit circuit so it didnt trip, and the fan run on full for about 1hr before the motor got too hot and a thermal trip on the back of it cut in.
take the cover off of the motor on the back and run the fan with less light, probably getting some arcing in the motor. This is what was killing mine the same way.
Interesting. I wonder if they had a faulty batch of motors perhaps. The fan was pretty much as new. No dust on it, or signs of use.
Great video, my first thought was to lubricate the motor bearing with something, somehow, what you done fixed the problem but if the bearing is dry or something which would cause the motor to draw more amps then there is a chance it will stop working again and maybe seize. Great video though. 👍
Thanks, the motor did seem to rotate smoothly and seemed to be lubricated, there was a number of these for sale at the time all in pretty new condition, I think bad batch of motors or something was the problem. I did run it at full power but the motor overheated after about an hour of use.
ohh great. they sold one of those to my motjer in law..but they didnt supply the batteries. she ended up paying about $700 for the fan and two batteries 🤦 (home depot friendly con team at work).
hopefully nothing too nasty going on with it.
btw ill always refer to waveform peaks as "the bit thats up" from now on 😂 brilliant.
😂👍
It seems to be a bad/poor design. Nice fix on your part!
Thanks Michael 👍
Hi I think is pattern bad design overdriving components and that's why they also blow fuses
Yep. I'd also agree!
could it be the bearings? heats up a little and gets tight, causing the extra load to hit the rpms...does it have an rpm sensor on the motor?
It does it almost immediately from cold, no rpm sensor just current sensing. I'm pretty sure it's the motor or too much load on it. I ran it at full by disabling the current sense and it ran for an hour but the motor was very hot and the thermal cutout kicked in. So either bad batch of motors or too much load on the motor I think.
Would be nice to have a perfect working one to compare data.
When at full speed it just pretty much powers the motor direct (100% duty cycle). I also tried bypassing the current limit so it did send 100% power, this worked for about 2 hours at which point the motor overheated and a thermal cut out kicked in. The motor looked brand new, turned smoothly etc which is why I think it's a design fault (asking too much from that motor) or possibly a bad batch of motors? But there were lots of these almost new units for sale with exactly the same fault...
Thanks for the vid. Good info
And thank you j s for watching!
Their using the lm324 as a pwm for fan speed my guess is a resistor on this circuit has gone high allowing the shutdown because it's going over current.
Not so sure on that, the NE555 seems to be providing the pwm and the lm324 seems to be used for current sensing. Someone sent me a picture of the motor which seems to be 18v 20w which would work out at 1.11a current draw? But the PSU they supply is rated at 2.5a and the fuse on the board isn't blown so are they just over driving the motor on purpose?
FANtastic
😂😂😂😂
Spot on. I was immediately thinking the same way because of where I work. You have multiple people well we like to call ourselves engineers but nevertheless I am the one designing the point of load circuit and I'm designing it with the specifications I was given from the prop designer who was determining what the load was going to be based on the designer of the motor and so on and guess what someone Fu ed up and believe it or not this type of mistake can make it all the way out the door in a poorly run engineering department. So the real mistake was the supervising engineer of the entire project who now works somewhere else. LOL. Shut up it's a true story different day same problem.
Thanks 👍
I'm only 15 minutes in an already everything is telling me too much current and shutting down for self-protect. When I test for something like this I like to remove the fan blades and allow the motor to rev in a no-load situation. if the problem goes away we know where to focus.
The fan is a nightmare to remove apparently. I did have a search at the time and there's quite a few people broke them trying to remove them for cleaning.
@@BuyitFixit Well then I would say that changes things a lit. Lol. Based on this I'd say you likely did the best you could in dealing with what appears to be a design flaw. When dealing with motors that draw too much current I have found that heating the armature a bit right near the bearing/bushing and then applying a bit of ptfe grease helps. You just want enough heat to melt it so that it has a chance to flow into the bushing. I actually just repaired a bathroom fan motor this way. it still turned freely by hand but wouldn't budge when powered on. The thing spins like new now.
Nice, thanks for the suggestions 👍🙂
Hello, can you tell me where to buy a 20 watt motor for it? It refuses to work with the RS 755 engine after installing the impeller on the shaft. The engine starts, then stops.
Sorry, I was unable to find a replacement motor myself. You could perhaps alter a couple of the current sense resistors on the op amp to allow more current.
i run mine at work daily for over a year and no issues. rhis is weird
Perhaps a bad batch of motors or design change perhaps.
seams like the high speed could be over amping and the circuit is shutting down for a safety ?
Yes, the motor is pulling too many amps for sure. The unit is almost new and the seller had about 10 listed with the same fault. Design fault? Bad batch of motors? I've seen other experience the same issue on reddit too...
Moisture in the motor can cause it to get stiff so it will cut out just oil the bearing.
The guy selling them was selling around 10 of them all with the same fault. All looked pretty much brand new. The motor was rotating freely by hand. I honestly think that it's a design issue. If I powered the motor direct it worked fine, but overheats after around an hour due to too much load on it.
Is there a missing cap next to the motor connection? A cap there might limit the initial current not the motor which might allow the motor to run if the current rose more slowly🤷♂️
Not a fix in my opinion. You can clearly hear the fan spin much slower now. You altered the design to compensate for a fault instead.
My primary suspect would be a partial fault with the op-amp. Or something alongside that current sensing/limiting circuitry.
Good point. I did try running changing the current sense threshold on the op amp but not on the video. The fan run for about an hour but then the motor was quite hot and seems to have a thermal cut out that triggered which reset once the temperature cooled back down. One of the reasons why I think it could be a faulty motor or too much load on the motor? Or a design flaw.
@@BuyitFixit Maybe justs needing lubrication? I feel stupid suggesting something so simple, but it would certainly explain a motor drawing more current than it should or getting hot.
Good suggestion but it seems to rotate freely by hand, doesn't seem like it needs any lubrication also its almost brand new.
I have same issues with my new two weeks old fan.
One day It stopped at fan speed 3. Sometimes it happens at speed 2 but the strangest part was that the next day it started to working again with no problem.
In rare cases when I turn it off and start it again for a couple of tries it works.
I live in California, and lately we have been experiencing increasing humidity levels, especially this summer. Perhaps that is the cause of the issue?
The most serious problem I think is that I reported it to the Milwaukee customer center, but have received no response.
Not sure on the humidity levels causing the problem..I honestly think it's just a bad design and they are asking too much from that motor.
Milwaukee are overrated chinese junk
D8 Looks like a Reverse Protection Diode.
My first guess was that there's a problem with the PWM feedback circuit, that is, too sensitive on the high speed setting.
Your change of R12 value has made high speed noticeably slower.
I did off camera change the current detection circuit which allowed the unit to run at full duty cycle but after about 2 hours the motor was very hot and it's thermal cut out kicked in. I think either a faulty batch of motors or too much load being placed on them. The seller had around 6 or 8 for sale all with the same fault and all in as new condition like this one.
Could it possibly be the switch itself I have one and when I pushed hard on it it started to work Intermitant
Possibly, hard to say without seeing the fault.
I wonder if its a finger protection circuit being triggered by an unbalanced fan?
Hmmm interesting thought! Didnt think of that one. It does have that sort of thing. It wouldn't explain why the motor overheats when its powered on full for an hour (I updated the video description with some additional stuff).
Sometimes That Stuff Has Too
Much Protechtion What Would
Happen If All That protechtion Was
Removed. Cause The Battery
Has Enough Protechtion
To Prevent The Motor From
Over Loading
The batteries actually don't have any output protection or under voltage protection. All of that is handled in the tool. They batteries only have charge protection.
Any idea if it was like that when new or did it develop the fault?
I'm not sure, but the seller was selling a few with the same fault, all looked in very good condition almost new, like this one.
Can the motor and cpu + can control be purchased online? My step dad said it’s pointless and I should just buy a new fan
No, I couldn't find any useful parts for this online except a couple of the plastics I think and a label. The motor has a quite large splined shaft and I did have a look on the usual chinese sites for a replacement without success. There is no CPU on this or software. It's just couple of standard readily available chips.
@@BuyitFixit guess my step dad was right 😂 no way in fixing this 😂
Surprised to see you're not on Odysee yet...
The problem is “It ain’t got no gas in it” 😂
😂😂😂😂
Dirty commutator on the motor.
I am just guessing here, but, it sounds as if the motor is not the correct one for the power.
Could well be
Drop oil in the sliding bearings
And damn I bought this fan 2 days ago new lol
From the number of faulty ones I've seen on Ebay with the same fault, I think there some design flaw. I think there is too much load on the motor or it's not up to spec. Unfortunately I'd not recommend this product.
@@BuyitFixit ahh should have bought 12v version no mains power but atleast no dramas.
Anyone knows where I can buy the DC motor ?
Unfortunately not. I had a search on the number that is on the side of it, but it didn't turn up any results 🙁
So are they over driving the motor on purpose?😅
That's was pretty much the conclusion I came to 😂😂😂
Bad design is my vote.
I think an engineering/R&D error!
Could well be 👍
Blowing in the wind🤣🤣🤣
Easiest Workaround: Stage 2. ;)
Ha! Good one Markus. I think that's what a lot of people would just end up doing.
Milwaukee Fan,Fan😀😀😀
😂😂😂😂😂👍
The motor probably uses permanent magnets. If they are poor quality and begin to lose their magnetism the motor current draw will increase.
These units were almost new, and the seller had quite s few for sale with the same fault... unless it was a faulty batch of motors?
Don't suppose you use ego 56v equipment, repacking batteries be good video, tools excellent..
Unfortunately not. I don't really use a lot of tools day to day but they are handy to have when I do need them.
@@BuyitFixit ego 56v gardening equipment is about best you can get, awesome outdoor gear 5yr warranty.
Ah right. I don't do a lot of gardening. The sheep etc keep the grass down 😂😂😂
@@BuyitFixit my sheep shearing days long past, even got the sore back still to prove it , 150 a day in my younger days.. lol 😆
Lol we've only got 50, our local friendly farmer helps out when we need that done and I fix his broken things👍👍😂😂
Hi, is there a way i can get in touch with you via email?
Yes. Email is on the channel about page 🙂
My money is on a component in the current sense circuit is off value.
Unfortunately not, I tried adjusting the current sense, and got the motor to power at full speed. I even tried powering the motor directly. The motor runs for about two hours and then overheats and cuts out with a thermal cutout, so I think possibly a bad batch of motors? or perhaps the fan pitch or size is just on the edge of what the motor can handle. The seller had a number of these for sale all with the same fault, and all in nearly as new condition.
design fault perhaps.
That was my thoughts, or perhaps a bad batch of motors?
This fan is awful. Brand new it won't stay on more then an hour on cold
Agree I think it's a design issue and the motor can't cope with such a big blade on it.
Mine has a similar problem.
I think it's a design fault, as when I bought this there was quite a few others listed with the exact same fault.
is this Gadget a Genuine Milwaukee Item I Use there stuff in the rescue Industry Is the Genuine AEG Product Or A Chinese Copy. My Buddy always Raved his Makita was top Notch till i showed him a Real One. His tag said made in China. Humans need to cut down Producing shit and go back to making tools and Cars that last a lifetime all this Corporate Greed mass Produce twaddle can not continue .
Yes, unfortunately it is a Genuine Milwaukee item. Totally agree with you, on a recent video I repaired / serviced a kitchen aid mixer, 34 years old it was, and I bet it will last another 34 years...
@@BuyitFixit kenwood chef 40 years old still perfect to this day was my mother's.
There will also be less shit going to landfills !
Hello, I have the same fan but it only works with the DC port powered by a cord with its battery it does not work. Do you have any video of this problem and how to solve it, thank you@@BuyitFixit
Q9 looks a bit dodgy
Thanks Ripley. I had a look at the video, and can't really see what you mean?
Design fault
I think so.
@3:38 - The only thing obvious to me is that this is overpriced tat with nothing whatever inside.