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medusa 70mm 2000kv wooooott!!!
so i receved my 2000kv 70mm this week....installed in my e-revo and tested...so after 20 min my motor was 160f:surprised:esc109f(fan spinning),batt 98f...temp outside -15 celcius(5f)
my set-up e-revo 16/68 6cell lipo mmmv3 timing lowest,punch contro; 50% mulcher serie40 tire all around 10awg wire and 6mm plug well...i think that im undergeared..(i hope)any idea thanks |
Seems a bit hot considering the outside temp! Shouldn't be kicking the fan on at all in those temps. Is there a lot of snow sticking to the truck? Gearing is for about 35-36MPH I believe which should be easy for that setup. 160 isn't horrible but 98 on the lipos in 5* ambient isn't great or the fact that the fan on the MMM is on. I'd def play with the gearing, gear down if the snow is sticking to your truck resulting in a 20lbs snowball at the end of your run! Which ever way you go, check temps often!
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16/68 ARE YOU SERIOUS! That sounds way overgeared to me. Medusa motors typically run 10 degrees or so cooler than an equivalent Neu, and my amp hog 1515 1.5D ran 140ish in 90-100 degree weather geared 22/62. If you have a smaller spur gear go ahead and put that on and your motor temps should drop.
Did you notice it was hitting full RPMs too quickly? That usually means you are overgeared, I almost never hit full RPMs out of either A) Fear of hitting something at that speed or B) Run out of room too fast. |
Yeah, I'd say its undergeared as well. Did you run a neu with that same setup/gearing? What were your temps with it?
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yes a 1515 1.5y and my temps was 80f....(no snow sticked in the truck)ive tryed each of my neu and they never pass 90f.....(1515 1y,1515 2.5d,1515 1,5d and 1515 1,5y)all this motor on 6 cell lipo, same temp outside same gearing,,,i will try to gear up today...maybe:yes: |
Gear up and see what happens.
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good news...i tried 18/68and ive got 108f(motor) after 25min at 10f outside
esc 105(fan spinning!!??) and my lipo was 79f:yes: i was undergeared thanks guy's:whistle: |
2 teeth on the pinion made that big of a difference :oh: I was thinking something more along the lines of a 58 or 62T spur :lol: As long as you already have the pinion and it did the job that's good (I usually suggest spur changes rather than pinion because they cost 1/4 as much).
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Sounds like you got your issue resolved by gearing up...but perhaps you should take a look at your timing as well. Medusa recommends 8-15 degrees on their website for best efficiency.
In the Medusa section last week one person was having overheat problems running 036-060-2200 in a 1/8 buggy with low timing. Problem was resolved by changing timing to "Normal 10." Maybe something you could consider experimenting with. |
last update on my motor....after 5 run it died:surprised:for me medusa are crap:yes:the magnet come appart the shaft ...it was 138f,esc118(v1) and lipo 96f
i will ppst pics later today |
Wow, that's the first one I've ever heard of coming apart. E-Mail them and they will probably replace it for free though.
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Plus you are spining the motor really fast on 6S, doesn't help when you are severly undergeared, hot and revving the piss out of it.
FWIW, my neu's magnet came off the chaft once as well. They fixed for free, or if you have the correct locktite (HD green for bearings iirc) you can do it yourself. |
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look...http://i44.tinypic.com/1zvy6if.jpg
so i know that my motor reached 158f(exactly)but i dont really think that is caused my failure...!!!??? and it was 10 mintes that ive running my truck and the revo stop suddenly.. |
Over revving the motor constantly (high rpms + low gearing = motor tops out very quickly and stays spinning at high rpms constantly when you are on the throttle).
Contact medusa and they will sort you out most likely, - I would do as the others suggest and swap it for a ~1600kv motor if you intend to use 6s lipo most of the time. 4s lipo = 1900-2200kv 5s lipo = 1700-2000kv 6s lipo = 1500-1800kv As a very rough guide- 4 pole motors tend to perform better when span slower and geared higher, unlike 2 pole motors that work better span faster and geared lower to make their power/torque (least thats the impression I gotten over the years). |
Completely understood, but that has happened with the best of them. I've seen Aveox (Some of the ones I have), Neu, Hacker and Lehner. It might be just a defect on the rotor's wrapping and the high RPM caused it to fail. Send it to Medusa and get the 1600Kv version for 6S lipos.
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for me medusa its the past.....i have a neu 1515 1,5d that ive run on 6 cell lipo and i never had any kind of issue,,,,and i dont understand they write on ther website that this motor can handle 30volt....?????
anyway its to late to send back to medusa the motor is in my garbage:yes: NOW IM LOOKING FOR A NEU CASTLE OR A 1515 1Y...nothing else...:whistle: |
You threw the motor away?!?! I'd have taken it in a heartbeat.... Or you could have gotten a new motor.... :diablo: :diablo: :diablo:
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I cant believe anyone would dismiss an entire (repsected and reliable) brand on the basis of one, just one broken motor- have you seen how many people have had issues with Neus? The magnets detach from the shaft or the shaft snaps just as easily as with the Medusa you know, only there are many more reported incidents with neus.
What happens if/when the neu gets an issue, and they wont warrenty it because they think user error is to blame (dirt inside the motor for example), will you dismiss neus too? The castle motors will be great, but the 2200kv is still abit high for my liking if you use 6s lipo constantly, but, thats your choice I guess, dont say we didnt warn you. :neutral: |
I agree. Stuff can happen with anything. Even if the damage isn't covered by warranty, a new Medusa costs well under 2 bills, which is much easier to swallow. Unless maximum quality/efficiency is absolutely needed, Medusa fits the bill perfectly. And they are a far bit better than Feigaos or similar motors.
The only other motor I can think of that would meet Medusas cost to quality ratio is a CC Neu, but kv choices are rather limited at the moment. Not to mention that they get larger (heavier) as kv gets lower since they are retaining the same wind and coil configuration, they just vary the length. |
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One of his MMM went up in flame, will he throw the 7 MMM away and never buy another one? He did it with the Medusa motor so what's stopping him from doing the same with the MMM. Call me the :diablo:, but I hope no one will use this thread as an excuse to not get a Medusa motor. Lets hope none of your Neu motors' have this issue.
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If that's the case, I'm sure there'll be a ton of potential Medusa and MMM buyers here...
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dont worries guy's i know that medusa made great motor..of sure there are not a lot of failure like that reported about the 70 mm can...so my motor is in the way....to medusa compagnie:whistle: i was just frustrated because in 2 days my mmmv3 went up in flame and the next day the magnet of my new motor come off of the shaft.....im just unlucky:oops:
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Sounds like the gearing changes are a good step towards that, but you still will be using the motor at its limits, so extra caution and conservative settings should be taken to avoid further failures until the setup is really tested and proven. |
wow now im confused.....im the r/c for about 10 years(in electric)and now i feel like a newbee....:lol: if the compagnie said that the motor can handle 30 volt and i push it to 25 volt its border line!!!????....wtf...my revo is geared like the stock revo bl edition...motor 200kv lower thant the neu castle...i dont really think im hard on the set-up if yes traxxas should not recommend to run the e-revo on 6 cell lipo...i run in my 2 other e-revo same exact set-up(18/68) but a neu 1515 1y and a 1515 1,5d(14/68) both on 6 cell lipo...my 1y never pass 128f(in 30 minute)and my 1,5d was 153f(after 33minutes)at 73f outside.. now(in my winter basher) i run a 1515 1,5y geared for the exact top speed that i was with my medusa....yesterday i run 48 min in line...ive got 98f on my motor at 39f outside..
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If your real car says max RPMs are 8000 are you going to run it at 8000RPMs everytime you get behind the wheel? Most like to leave some headroom for safety. Also remember that in General most of us are running a lot of WOT in our RCs unlike a 1:1 where a tranny shifts and you cruise at maybe 1/4-1/3 the redline RPMs.
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right...!!but run a motor on 6 cell like the 2000kv 70mm does not seem that your always in the red line.....50 000rpm at 25 volt its away from the 60 rpm rated....and my motor was only 138f... |
High RPM and high load causes issues. Try the 2000Kv with 4S lipos and see how it does. If it's too slow for you, just get a bigger pinion. I run my BPP truggy with a 1577Kv motor on 5S (29175rpm) most of the time, but to show off I use 6S (35009rpm). Now my other truggy I run 8S with a 1100Kv (32560rpm) motor and it has proven to be my most efficient and powerful set up yet due to the characteristics of a lower wind motor offering higher torque (Shaft bending torque to e exact).
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Here is your setup as I understand it right?
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The reason the motor heated up so much was b/c of the low gear. Efficiency is quite low w/ low motor loads, plus the rpms and voltage will be higher than what is listed. This is evidenced by the 160F motor temp at 5F ambient. Inside that little furnace the magnet was prolly 200F+. Now as far as Medusa's specs, they also list the motor as 1100W. Your setup will easily pull twice that (say 120A at 21V+2500W.) Remember these are plane motors. You can do high rpms in a fast moving plane that draws a fairly steady amount of power. Not the peaky power cars do. 2500W->300W---> 2300W--->brake-->2500W--100W, etc all in a few secs. Now a medusa can prolly handle it, but everything else needs to be setup just right as well or its asking for trouble. IDK and don't care what TRX lists for gearing. The above is true. Now the inside gets very hot, high rpms...boom goes the magnet. You can see it came right off the shaft. Now maybe it was just faulty anyway, and had nothing to do with the setup. I had a Neu that did the same w/o warning and never got above 120F. The mag isn't wrapped, so it smacks the coils and you have one fubared motor. If thats the speed you want I would drop voltage or kvs. Its like having a 500hp supercharged v8 and leaving it in 2nd gear bc you don't want to go too fast while you are flooring it. It just isn't gonna last |
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IMO, 42k rpm isn't really that high on a quality motor. The good motors are rated up to 50-60k rpm. Of course we shouldn't run them near that high, but 42k is only 70% of the 60k max, so it should be just fine. And true, the efficiency of an unloaded (or very lightly loaded motor) isn't great, but in a vehicle geared for anything over 14mph, it should be more than enough load. Besides, that 42k rpm is probably using the unloaded kv, so it will drop the more current you pull.
It's one thing if you were doing speed runs only hitting WOT all the time because it was geared so low, but on a track, the throttle is mostly somewhere in between slow and WOT. |
next time i will try to gear up....so its the first time that ive seen a motor that ive proble to set-up correctly....
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42K is not high per se, as said it would be fine in a plane app where your constant power pull is within specs. However we do use rpm as proxy for power, where the rule is (was) 28-32K was great for trackable levels of power in a 1/8th truggy or Revo. This yielded about 1500-1800W. Ie a 1Y on 4S, geared properly for ~40mph.
Take that same 1Y and spin to 42K, ie 6S. Geared the same that's more like 60mph. Amp draw is about same, but voltage increases by 50%. So does power then. So you try to tone down the power/speed by gearing down, but now you are unloading the motor. I wish Lehner still had the graphs up, but they had very detailed data on load vs input/output power. Even for high end motors that reach 90%+ efficiency, at low loads, eff dropped to as bad as 50%, quite remarkably. Overloading the motor does not produce such drops. So even if you are not producing that much power, the heat losses can still be terrible due to low eff. Try slow spd driving, sand (or snow) driving or driving w/ a loose slipper where the motor is lowly loaded. They will heat up the motor faster than high spd runs. You are far better off just dropping the cell count than the tooth count to get the desired speeds. If you want more runtime, use larger cells, not more of them (if you leave the motor the same.) Much has been made of the gearing, but the driving environment also is a factor. If you have the Revo all covered w/ snow, revving to the max and just kinda plowing thru snow drifts w/ big snowy rooster tails , then yea, that's a real challenge for any motor to stand up to. |
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Your motor was probably spinning too fast. There is a range of rpms which the motor will operate at its max efficiency. Check with medusa and gear it accordingly. I am very interested in getting a 70mm medusa too. Do drop me a note on how the motor performs when u get your motor back. :D |
I'd run 8-15 degrees of timing on a 4 pole motor. Start off with 8 and work your way up to where you like it.
I'm loving my 70mm, geared 18/46 in my Hyper 7 after a run the motor is around 90-100 and my ESC is about 20 degrees warmer than ambient. I've got a 24T sitting here that I'll try on it next. |
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