Question for Patrick
 

Hi Patrick,

I have a Recoil and I went to test it out today with the Mamba Max and it ran hot. The motor I'm using is the Mega ACn16/15/1 (9200Kv) and the gearing is 16T/58T. Now the funny thing is that I was using a 60A ESC and it was working really good until I changed the timing setting and I burned some FETs. The 60A ran about 4-5 hours and never got as hot as the Mamba Max did today. I have the newest firmware and all, but what is the appropriate timing you recommend for a 6 pole motor. Most other companies recommend 15-30 degrees of timing, 15 being for optimum performance and 30 for maximum power.

Regards.

9200kv??? What is the rpm limit of the Max with a six pole? I know that a four pole is double the processing so the limit is halved, but what would that six pole'r do to the equation?

Fair point this would be the equivalent of a 27000kv feigao... What voltage were you using?

I'm only using 2S Thunder Power 2200mAh Extreme V2.

I know a few controllers that can go up to 240,000rpm for 2 pole, 120,000 for 4 pole, 80,000 for 6 pole and 40,000 for 12 poles. I will wait to see what Patrick will say though as I'm not an engineer.

That is quite a strain for any controller, actually. The MM has to have a 240K limit for 2 polers otherwise you couldn't use this setup.

7.4*9200=68080, and being a 6 pole motor- 68080*3=204240. It's like running 204K rpm with a 2 pole motor! :oh: That will stress ANY controller.

Yeah I've heard the same about the 15-30* timing. What setting are you on now? Have you tried it at a lower setting?

Didn't strain the 60A I had in there before. That controller burned the FETs due to me not paying attention to the program box. I set the wrong timing instead of something else. The MM is actually running it ok, accept it's getting hot and the small 60A controller wasn't. I know people put the MM through worst and I can't seem to understand why it's heating like this in a small car with a small motor that is asking for max 40A.

The timing I have now is normal (10) and I haven't tried any other setting as today was the first day at the track with it. I'm afraid to lower the timing and have similar issues that I had with the other controller.

It could be the same "problem" people are seeing when the go from the MM to the MMM. Some were complaining that a setup which ran fine on the MM was now getting too hot with the MMM. The FETs in the MM may be much lower resistance than your 60A controller and so allow a much higher pulse current to pass through to the motor. Is the motor getting hot too? If not, I'm kinda stumped... That's all I can come up with right now.

The 60A uses the same FETs (At least I think it is) as the MM. The motor's temp is normal.

Yep. I'm stumped. :neutral: PAATRICKKK!!! Hellllp!

Lutach,

What timing are you running now, when you see the temperature problem?

I'm kind of skeptical that a 6 pole 9200Kv motor will ever work really well -- the commutation frequency is so high that the recirculating currents will never cease -- there will be recirculating currents running through all three phases all the time.

I don't know where the best timing would be for that kind of motor. I'd think you would need to set the timing kind of high, but I'd need to look at it with an oscilloscope to be sure.

Patrick

Patrick,

I have the timing set to normal. Let me know the best timing for this little high RPM motor.

Regards.

QFT
:smile:

Is there such a controller which has variable timing, not just incremental? That way you could "tune" your brushless setup.

I thought I read somewhere thats how sensorless BL esc's worked (castles in particular) - that the timing varies with the RPM. I also read (in the drivers ed guide maybe? cant remember) that the esc detects the optimum value for the timing, and the timing adjustment just varies it within that optimal range. Does this sound right?

Yep, the timing is variable on Castle's ESCs. You set the range it stays in, and it automatically adjusts timing based on load and RPM of the motor.

That's what I was about to ask Patrick. I got timing set at high right now and I'll see what happens when I try it out on Monday.

Ahh, I see....and knowing is half the battle! :lol:

mamba monster combos
 

hi i was wondering about the monster 2200 combo i have seen it on back order with certain shops saying delivery will start the week comencing 25 august but i cant find anything about the combo date on castle web sight
can you tell me if this would be correct or is this shop just teasing me

Please look here: http://www.rc-monster.com/forum/showthread.php?t=13919.

Patrick,

Just came back from running the Recoil. I changed the timing from normal to high and it still heats up pretty good. I'm going to try the smallest pinion I can fit in the car and see if temps go down. Motor wasn't as hot as it was with normal timing though.

Here is a data I got from running the Recoil at the track.

http://i260.photobucket.com/albums/i...5-19200Kva.jpg


The MM still heats up even though max AMP spikes are in the high 50's. I even installed a 16T pinion in place of the 19T that was in the car before with the 60A controller. Patrick, what is the max RPM the MM can go with a 6 pole motor?

wow. i managed to take out 150A spikes with the Mamba max and it wasnt even warm!! lets hope you can get this sorted :)

That's why I can't understand why the MM is heating up like this.

That is strange, it heating up on an average of 3.05 amps. I know the peaks are higher, Just thinking the average would be the culprit. Before the update that allowed us to run Neu motors on mamba's, I seen cog spikes of 120amps on a mamba 25 (on 3s lipo) and it would get warm, but not what i would say was hot. For those that think its too early to do math (saturday as well) that was 1000+watts through the little mamba, tough little buggers :yes:

There were a few guys at the track who are racers and couldn't understand why it was getting that hot. I'll wait for Patrick to give an answer of what is the max RPM for a 6 pole motor.

It's not the max RPM (commutation limit) that is at issue here. It's the fact that the recirculation currents are continuing (probably) almost all the time -- this is VERY hard on the ESC, as all the body diodes on all the FETs will be conducting for a significant amount of time.

Again, I would be surprised if you can ever get a 6 pole 9200Kv motor working well. That's just not a good idea.



We tested some of the CC Neu motors to destruction the other day, and the MMM had no issues running a 4 pole motor at 150,000 RPM. So commutation frequency maximum isn't the issue here.

Have you tried it with low timing? That might help reduce the recirculation currents somewhat.

But I still don't think a 9200Kv 6 pole is a good idea. 2 pole is pushing it with a 36mm motor and 9200Kv...:gasp:

Sweet, I was planning to aim for that kind of RPM too :lol:

On a serious note though, how'd you test that? At a guess you either had a custom super HV version of the MMM, or did a super high Kv custom wind to test with?

Well, we only hit 150,000 on one of the 2600 Kv (1512) motors, at 56V.

It was an HV.

Ok, just to clear one thing up, the 2 initial motors to be offered are a 1512 2600kv and a 1515 2200kv???

Thanks Mr. Patrick....

Yep, that's right. We will be offering others, but those will be the first two.

Will the motors only be avalible as a combo or will they be sold seperatly?

Thanks... Any idea of pricing on the motors by themselves? Somewhere between $100 to $200...

An HV MMM? Release date? Preorders? :whistle:


I kid, I kid :oops:

Roughly how long would you say a Neu could operate for at say 100,000 rpm? I know they are only rated for 60,000, but just once I want to hear what 100,000 rpm sounds like with a big motor. Would one need to upgrade the bearings? Just curious... :mdr:

OK---

1. Available as combos and alone.

2. HV MMM -- yes, it is coming. Someday. Not real soon.

3. Watch for motor pricing on our website. They were a little more expensive to build than we originally thought.

4. Some of our samples didn't even make 100,000 -- they failed in the 85-90K RPM range. So, I can't recommend ever running the motors over 60K RPM.

Thanx!

Thanks for the reply, is there a pre-order soon on the motors? (I will be getting the 1512 2600kv asap)

When the motors failed during testing was it due to bearings or some other component like magnets seperating?

Well, we've never had a bearing failure during testing. We are using Japanese CNC quality bearings that are rated to above 100K RPM.

It's always a magnet (epoxy, Kevlar wrap, cracking, etc.) failure at high RPM.

RSN -- :yes: