Hi! Does anyone have any experience with operating a Mamba Max Pro (MMP) close to its RPM / commutation rate limit?

I'm planning on running a 6-pole 3700kv motor (Turnigy 2836) on 4S with the MMP, but I'm not completely sure that will work flawlessly, because of the required commutation rate (373k/min fully charged and 329k/min @ nominal voltage – no load obviously, so real world figures will be a bit lower fortunately).

I've looked around in other threads and found a post in which a Castle tech was quoted, saying Castle's ESC's can commutate up to approximately 320k/min. I also contacted Castle myself, and the same tech that was quoted in the earlier mentioned post told me the commutation rate of all Castle car ESCs is around 280k/min, so they're not that consistent with the info they're providing... Anyway, I also have a 3200kv 6-pole motor and did a no-load (empty shaft) bench test with it on a fully charged 4S pack with the MMP and nothing funky happened at full throttle (should be around 4*4,2*3200*6=323k commutations/min), so I guess the 320k limit is closer to the truth than the 280k.

Does anyone know (out of own experience) what happens when the ESC’s RPM/commutation rate limit is reached? Will it be like a hitting rev limiter or is there a chance of damage to ESC or motor? Any real life experiences (to what maximum commutation rate did you push your MMP?) are much appreciated.

Thanks!

Your looking for a 'max rpm' number when using a 6 pole motor?

I've pushed 2 pole motors over 100k RPM on the MMP.

I know others have used the castle 2650 4 pole on 6 cell(60k rpm). (~120k vs 2 pole)

With your 2836kv 6 pole ~14.8v is ~ 126k RPM vs 2 pole.


The ESCs don't have a built in RPM limit like some do.

yes please

I edited the post...


You might run into heat issues, IDK...

OK, thanks. I have already done 4*4,2*3200*6~323k commutations/min (~54k 6-pole RPMs, equivalent to ~161k 2-pole RPMs) on it in a no-load bench test - and under normal load in a Losi Mini 8ight that configuration runs perfectly smooth.

Question is if it could be pushed to do 4*4,2*3700*6=373k commutations/min (i.e., ~62k 6-pole RPMs, equivalent to ~186k 2-pole RPMs) max under no-load conditions.

Anyone successfully did more than 323k commutations/min (~54k 6-pole RPMs, equivalent to ~161k 2-pole RPMs) with the Mamba Max Pro?

There's very little info on this for surface ESCs (although the China made ones from Hobbyking do list higher RPMs for >4-pole motors). For anyone who's interested, here is a reference list of some air ESC’s showing their limits:

http://www.bavaria-direct.co.za/mode...ontrollers.pdf

Castle's cheapest ESCs will almost do what you want, I don't see any reason why a MMP wouldn't work.

Your probably not going to find a definitive answer on here. Try RC-monster


I would love to see a motor that would spin 360,000 RPM

Is the number castle quotes as max in sensored or unsensored mode? I know there are issues with sensors over a certain rpm but never heard of max rpm unsensored. Also be careful doing a no load rpm check. Good way to destroy the motor.

I have talked with Castle and have also received the 280k number. My wife is running a 870kv 14-pole outrunner on 6s with a MMP 1-cell ESC in her TLR 22T Stadium Truck. So, her numbers are 25.2 volts * 870 = 21924 RPM * 7 = 153468. We have had zero issues with that setup. I also run an outrunner with mine, but only have a 138600 rate. Both are sensorless.

Oh, is that not good? Didn't know that... still a bit new to RC, thanks for the warning!

I'm not completely sure, but don't think the quoted RPM limit applies to sensored-only, as one of the techs I contacted said all Castle's surface ESC have the same RPM limits (and not all support sensored).

Wow, a 22T on 6S, how cool! I thought all the 22/22T folks were die-hard-2S-only-racers I'm planning on getting a 22T RTR (for fun, I'm not a racer), and would want to experiment with some other motors and >3S a bit, but it's hard finding some good info on that. What are the specs on that 14-pole motor and what gearing does your wife use?

Thanks for the reply!

Her motor is:

http://www.hobbypartz.com/96m603-big...826-870kv.html

I run a 930kv in mine:

http://www.innov8tivedesigns.com/pro...roducts_id=840

I really like the Cobra because of the larger bearings.

We're both running 26/72.

Here's a short vid of my truck with the Cobra 930

+ YouTube Video

Very cool! Thanks for posting!!! Gotta love those outrunners, awesome power/weight ratios and tons of torque

Last night I won an ebay auction on a brand new T22 RTR; will sell the stock electronics, and still have a spare 3500kv H2223 laying around from my Mini 8ight that I think I'm gonna start with. It's only a 28mm can, but it's rated at 600W (burst probably), so should be ok for now if not geared too high.