While #1 and #3 are common sensorless symptoms, I have NEVER seen that happen with my Quark 125.

Is maybe #2 because of the relatively large motor you have on there? I know it technically works, but the MM was never designed to be used for 1/8 scale apps with large motors. It would be nice if CC could fix this though as the MM can obviously handle the load for the most part.

Here's a thought; does #2 have anything to do with the use of a 4 pole motor? Maybe try a regualr 2 pole, like a Wanderer as a test. After all, it's only $90. A 7XL or 8XL should approximate the Neu you are running pretty well. Of course there will be differences, but it's just a test.

#2 glitching is with a stock Mamba Max system... in a 1/10 buggy. We are running htem exactly as they were meant to be used, and everything is great except for this occasional hiccup.

The other cogging issues are with the 1/8 stuff and big motors etc and I can't fault the MM for that... although I'm expecting CC to cure this with software updates.

I've got #3 with my system, which I've mentioned before in other threads. To recap, I've got a 1/8 truggy with the MM esc and a Neu 1512/2.5D motor running on 4s (or 6s) li-ions. The radio is a Spektrum DX3. I'm glad that I'm not the only one with the problem. At first I thought I got a bum esc. Hopefully, CC will come up with a software update to fix all these problems.

I'm no sensorless expert (I actually have an HV in my G2R...so I dont worry about any motor issues of the sort), but I read the thread and thought it was rather interesting.

Is it something you can do on purpose if you tried? Would pumping the throttle eleminate it?

I run on a very tight track (meant for 1/10 buggies and ST's) and when I used to have my E-Maxx with stock motors (lol...those were the days) whenever I had any issue with cogging a quick pump of the throttle would solve it. Same goes with braking. It doesn't even have to be a total return to neutral, just simply reduce whatever imput you are giving for a fraction of a second.

Just a thought...

I am also kind of concerned because I am thinking on getting the MMM when it comes out (probably with the slipperential), and I figured it will have similar programming to the MM. I am racing with it and at the speeds I drive my truck I can't afford any glitching. I take corners at the point that I rely on the weight transfer to keep enough traction to keep me from spinning out. I have taken corners so fast I've ejected batteries from my G2R chassis...lol

I have faith they will fix #3... and I would think the MMM will not have problems since it will be designed and tested with the big motors. Just like the MM doesn't cog in 1/10 cars with the MM motors. (except for Brian's #2 reverse-to-forward thing) :)

I race hard and can't afford any glitching either, which is why I've been working on CC to look into it. Last night I stuck it in a pipe on the last lap of qual and slipped 3 spots in the main with that bobble... There are a few locals that kick my butt here that are close to top factory driver skills...

Small update: I raced last night and had less trouble than last time. I had reset the radio end points for the brake back to maximum (160% on the M8) and used the MM software to dial out the brake instead. It ended up on 20% on the MM and 150% on the radio. And the drag brake was at 30-35%

This seemed to do a lot better, although I had one definitely glitch entering a sweeper. It was a little different than what I was getting before. But it was the ony one like it out of about 6 packs I ran. Good news there...

The thing I didn't like last night was that the power or powerband feels a little inconsistent from lap to lap, corner to corner.... one minute it's a missle and then out of the next corner it seems to lack the same snap. Not a big difference, just something sublte.... but you can tell it's not the same every time you get on it. I have an old Novak Cyclone that is like that, only much worse...

I have no idea what to think about this. I don't recall this at all when I first got it. Last night there was a ton of traction and I had the slipper a little tight, so it could pull the front off the ground coming off the corners. This was mainly where the inconsistency showed... if I had the slipper loosened up I'm sure it would be much less noticable.

I don't know if I'm familiar with it now so I notice little things the more I run it or what... I want to swap it out for a differnet esc and see if it feels the same.

My glitch with the 5700 mamba was like 1 and 3, never had 2 happen, but always wondered if it was possible

I've had that occational glitch, like a momentary brake stab. Init thought it was a Rx problem, and started moving things around. Went away a bit w/ an FM and Rx pack, but it happens every now and then (unfortuantely after I nail the throotle and get going then, whack, then back to accel.


:032:

I was reading back through this thread and just thought of something that may help. This quote from GD got me thinking:

What if there is too much noise on the motor/ESC wires under high current during startup so the ESC has a hard time correctly reading the feedback pulses? Or maybe there is some cross-induction of this feedback confusing the controller?

What I am going to try tomorrow is somehow shielding each motor wire from each other and then trying to duplicate the issue I'm having. However, my symptoms are not very consistent so it might be tough.

It's a shot in the dark, but worth a try. I'll report back tomorrow...

I have my wires braides on my 5700 and not on the mamba/9XL, I mean its possible but don't think it will matter. Good luck in tring to make it happen

I haved wondered if braiding would make a differnence...

The thing about the glitch we have is that it's typically not under heavy load, like when you are just starting to accelreate hard out of a corner (from close to a standstill) but more when you gently get on the gas.... or are already at partial speed and then pull throttle.

I have my wires braided, but my glitch is when its going a bit (not form a stop) and accelerating.

Glassdoctor, What do you have the timing set at? It may be possible that its trying to out-accelerate the motor, I run my timing at the lowest point and have no problems.When i get a front arm for my T4 i will try higher timing and see if i can get mine to do it.

I have my timing set to low and I still get the cogging when doing the reverse-brake-forward thing.

you mean the foreward cogg while still going backward? I get that, but thought it was because the esc was confused and needed to stop before going foreward.

I have tried all the timing setttings... in my buggy/4600 setup I start at normal and go up/down a notch if I want more/less power.

At the race the other night I ran both normal and high timing.

Ok, I was thinking that at a higher setting the esc might be trying to anticipate the acceleration, Just a thought

You may have a point crazyjr... I'm not sure. I might try going to both extremes on the timing and just see what happens in the future.

I have mine set to the lowest right now because everytime i run it i break something, but no trouble

I had another thought on this subject (uh oh, lol), If the shrinkwrap on a couple of the plugs weren't completely covering the plug, would it be possible for them to touch of the feedback signal to jump the small gap between the plugs? My 5700 has one that is not perfect and thought if two or more were not right, there could be a problem

That is possible, but it takes fairly high voltage to arc across even a small air gap. The electrodes would have to be VERY close together. But, if they were touching, that would short the motor wires and cause substantial ESC heat, if not immediate shutdown.

According to Wikipedia, it takes about 30,000v/cm to arc across air. I don't know if the induced feedback signals can spike high enough to get to that point.

Interesting though.

That could explain alot about how fair a spark will jump on a automobile.
I think at 30,000v/cm would free a esc if it got high enough to jump a .5cm.

Wires normally jump up and down, from side to side..

I would not run my bl controller with naked wires.

just a thought, i have run both of mine in the last two days and have seen absolutely no problems, Except for the cog from rolling reverse to foreward, which i believe is a condition of sensorless, My Novak's never had that cog

Lol, I would hope not! What I think he meant (and correct if I am wrong) is that if you don't have the heatshrink totally covering the connectors (like a 0.5mm sliver of the connector showing) the feedback signal could arc across the connections.

crazyjr: The cogg from reverse to forward doesn't happen with my Quark though. That's why I thought it was an ESC firmware bug. Speaking of Quark; my 125B has a ferrite core covering the power wires. I wonder if something like this would help if done to the MM? The ferrite is supposed to inhibit RF noise from entering the power wire. The Quark also has a ferrite core on the throttle wire as well, presumably for the same reason. Just gotta be careful it doesn't slide along the power wires and short out on the circuit board.

I still think it's a software/firmware issue...

That's odd... My dad has an old transformer that takes 120v AC and transforms it to 15,000v AC (it's basically a ~40-50lb chunk of copper). We have gotten it to arc at up to 2cm in normal air. I wonder if there's some sort of "special" air that the 30,000v/cm came from :005:.

There are several factors that could attribute to the insonsistency you cited:

1: Moisture content in the air will make a difference. More moisture lowers the air resistance so it will arc easier so the electrodes can be further apart.

2: A transformer's output voltage rating is the value when pulling a certain amount of current. If you add a heavier load, the secondary voltage will drop. Pull less than the rating and the voltage will increase. Perfect example are those "wall warts". Ever measure a "9v" supply with no load? It's more like 12-15v. Once you load it to it's rated current, the output drops to near 9v. An exception to this is if there is a built-in regulator of course.

3: A transformers output voltage depends on the input voltage and the turns ratio. For instance; if a transformer is rated to put out 15,000v when a 110v input is applied, that is a 136.36:1 ratio. If the primary is at 120v, the secondary is actually over 16,300v.

Add all these variables and it could make a substantial difference. I'm not saying that Wikipedia is absolutely correct, but it does sound fairly close from my electronics classes oh so many years ago. :)

And did it start sparking at two cm or did you need to hold the wires closer to get the spark started?

Sometimes it would arc at 2cm, but other times it would only happen by starting with the wires (electrodes?) closer together.

BrianG, good points!

this is the exact same prob I'm having also.. running hard then a brake stab,next thing I know its on the lid sliding..
phil

I heard some one had a problem like this with a bk. It was a bad glitch.

Found this on the castle website in FAQ, perhaps this may help:


What got me wondering about this is philldogg's reply where he is experiencing a simular but more severe hiccup. He's using a 7xl, which would draw even more current than my 8xl, perhaps the controller is suddenyl dropping the motor power under extreme loads (like under hard accel) which may look like a brake stab under the right circumstance...

Don't have to do the "back to neutral" to go again, but maybe this is plane esc specific.

May not be the solution, but this fits the facts my particular hiccup, which is different than the rev to forward cogging some of you are encountering.

I'm running a 9XL on 12 cells NIMH 4400 max amps batteries and have no problems with it running, only rolling backwards and stabbing foreward causes a cog. I would've figured that a 9XL in an undervolt environment (according to others here) would cause a high current problem. I got some 2s 8000 mah lipo's coming and may can make something happen with those

Edit: Just a thought, How many of you with the Neu motors are running the 1/2 winds? I know there is a update coming to allow you to use the Novak and other 1/2 winds wothout problems. Just a thought

I was wondering if it might be radio related also because it is only sometimes.. I'm going to charge up the 12 cells (gp3300) tomorrow and try them.. I think the batts should be fine (6k maxamps) esp. since they went up in price and claim more amps now..not sure but will try the other batts tomorrow..
phil

Well, I'm using a Spektrum and you're right, it does only happen sometimes (the reverse to forward cogging). But I think it only happens occasionally because sometimes the rotot is in a "good" position.

cogging sound
 

It may be possible that it is not the ESC that is making the cogging sound. It may be one of your differentials, look at you manual and you will see the CV shaft and a pin that the gear leys over. That pin can slippe behind that gear if there is no steel shim between the diff cup and the pin.
To check this you may need to remove the drive shafts and check the amount of play. Grip the CV cup and pull and push tours the diff cup note the amount of play. There needs to be no play there (in and out movement) but the shaft needs two spin freely. You can see where the pin is slips (rubbing marks) on the back of the gear. When you are shimming the CV shaft end play you will want to check the planetary gears you may need to shim them closer this will not tighten the clearance it is just to get more of the gears to meshes (more tooth to tooth). Remember the nitro engine does not have the torque out put brushless has, and the diff tolerance was not engineered for BL. So we will need to tighten up the tolerances. Granger CO. has a large selection of shims. OFNA hyper 8 is my buggy and I ordered Shims 24@ 4mm x 6mm x.26mm and 12@ 6mm x12 mm x.26mm

Welcome to the forums!

In a buggy, yeah, shimming could be a culprit. But in my case it,s on a Jato and the design is totally different. In my case, it only happens after reverse, brake, then trying to go forward and it doesn't matter if I go gentle on the throttle or mash it.

Also, people have found that when this "cogging" happens, the current draw is substantially higher than normal, which leads me to believe it's an ESC fault. I halso have a Revo with a Quark that does not have this problem so I tend to lean toward the ESC being at fault.

That is the cogging I see.

The first time at the track I only saw very basic cogging from a dead start. This was during a 10 minute B-main and then during a 15 minute A-main. This is with the Mamba Max on a Neu 1512 2.5D with 4S 5AH Enerland Li-Pos. I was quite hapy with the small amount of occasional cogging since the system is in a 8.5 pound Hyper 7 1/8 buggy.

I got the idea to crank up the drag brake from 20% to 40% so I could just let off the throttle on the turns, transfer the weight to the front, and make sharp turns. At the track it wound up being a bit too much so I went to 30% drag brake. What happened though was the occasional cogging was still there, but sometimes I could not get going forward at all again unless I gave it a push. In fact, the buggy crawls backwards a bit when doing this severe cogging. I drove over to my starting place for the main race starting and stopping a few times, but when it came time for the start of the race I was left shuttering moving slightly backwards. Luckily the nearby turn marshall gave me a push with his foot and off I went.

it doens't seem like the change in drag brake should have caused this, but since I never saw that problem on my previous visit to the track it makes me wonder. It was the ONLY change I made (timing, punch.... all the same). The severe cogging happened three or four times and I only ran the 10 minute B-main. Before the drag brake change I never saw it once with over twice the amount of time at the wheel.
I set it back to 20% and hope to get to the track for some practice runs this holiday break.

Matt

Sounds exactly like the cogging I saw on the Mamba with the Neu. The 2 polers run better on the quark. I know that CC is working on a software update to make it handle the multi pole motors better. But no ETA on it yet.

Just be careful with the cogging. Thats when mine when up in a cloud of smoke.

[QUOTE=jhautz] The 2 polers run better on the quark. QUOTE]

A presume you mean "4 Polers" not "2".

:032:

nope. I think he means 2pole. Cause the 4 pole neu had more cogging than
the 2 pole lmt. The lmt would spin tires while the other just cogged.