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Pdelcast
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12.12.2017, 02:57 PM

Quote:
Originally Posted by maxxximatoze View Post
OK, it's certainly perfectly fine. Do you if high grade ceramic bearing can reduce I0 in a measurable manner, or it's useless ? (and make it run noise free, the orignal bearings tend to make some noise at different rpm)

Ps: what is the toshiba mosfet ref used in the mamba monster X, if it's not top secret, TPHR6503PL ? just to know... And I promise, I stop bother you with all my questions ;)
Ceramic bearings can make it both quieter and reduce IO -- but be careful, they damage easy. And the front bearing is especially easy to damage.

I can't comment on what MOSFETs we use. But you can probably read the numbers off the top of the chips if you are interested. :)


Patrick del Castillo
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maxxximatoze
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12.13.2017, 04:30 AM

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Originally Posted by Pdelcast View Post
Ceramic bearings can make it both quieter and reduce IO -- but be careful, they damage easy. And the front bearing is especially easy to damage.

I can't comment on what MOSFETs we use. But you can probably read the numbers off the top of the chips if you are interested. :)
OK no problem ;) . Mamba monster X can be removed from it's plastic box ? I don't want to ruin my brand new esc just to see the mosfet ref...
   
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Pdelcast
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12.14.2017, 01:24 PM

Quote:
Originally Posted by maxxximatoze View Post
OK no problem ;) . Mamba monster X can be removed from it's plastic box ? I don't want to ruin my brand new esc just to see the mosfet ref...
Well, no. The heatsink would have to be removed to read the chips, and that would void any warranty.

Sorry.


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maxxximatoze
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12.14.2017, 05:57 PM

OK so I will NOT take that risk ! I will have to wait for it to burn... Is the monster X prone to self combustion ? :) Do you know a compatible motor mount for the Hpi apache/vorza to put the 1515 sensored in the chassis ?
   
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maxxximatoze
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12.20.2017, 04:13 AM

For info (and memory for me)

I have measured again I0, but this time with a higher motor temp (around 60C) and the kv is rising up a little with temp (from 2220 to 2250) and I0 go down a little (-300mA from 4A to 3.7A@24V and from 3A to 2.7A@16V)

So the calculated max efficiency at 60C of the motor is 93.7% for 16V and 91A (50W copper losses and 43W iron losses), and 94.0% at 24V and 131A (106W copper losses and 89W iron losses)

The esc+motor max efficiency is calculated to be around 90/91% for 16/24V

In fine, it's a pretty good motor with some high efficiency :)
I'm curious to see what would happen with hybrid ceramic bearing. I think I will do some tests later.
   
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01.08.2018, 01:44 PM

Quote:
Originally Posted by maxxximatoze View Post
For info (and memory for me)

I have measured again I0, but this time with a higher motor temp (around 60C) and the kv is rising up a little with temp (from 2220 to 2250) and I0 go down a little (-300mA from 4A to 3.7A@24V and from 3A to 2.7A@16V)

So the calculated max efficiency at 60C of the motor is 93.7% for 16V and 91A (50W copper losses and 43W iron losses), and 94.0% at 24V and 131A (106W copper losses and 89W iron losses)

The esc+motor max efficiency is calculated to be around 90/91% for 16/24V

In fine, it's a pretty good motor with some high efficiency :)
I'm curious to see what would happen with hybrid ceramic bearing. I think I will do some tests later.
Ceramic bearing may decrease IO somewhat. But I wouldn't expect much of a difference.

When you compare our motor with others, you will notice our IO is very low, and efficiency higher.


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maxxximatoze
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09.10.2018, 10:18 AM

After a few months passed with this MMX/1515 sensored combo in my car, I can say that I'am prettu satisfied with the result until now. The combo is powerfull and reliable (2.02 firmware), but I have two question:

1) what is the ESC overheat temperature treshold (80C ?) and what is the audible tone sequence to inform the user of this state ?

2) What is the over current limiter setting and why we cannot set it like with the XLX? it seems to be around 150/160 amps continuous (for at leat 4 seconds), because I can't get above this max value and the KV of the 1515, which is at 2220rpm/V no load, drops to 1700rpm/V which is a big difference with only about 5 mohms phase resistance (with turnigy graphene 10Ah 25C continous discharge measured with wayne giles IR meter V2) see graph below.

Thx !

Full size link: http://maxime.pierron79.free.fr/maxpowertest.png
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Last edited by maxxximatoze; 09.10.2018 at 10:30 AM.
   
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Pdelcast
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09.12.2018, 12:22 PM

Quote:
Originally Posted by maxxximatoze View Post
After a few months passed with this MMX/1515 sensored combo in my car, I can say that I'am prettu satisfied with the result until now. The combo is powerfull and reliable (2.02 firmware), but I have two question:

1) what is the ESC overheat temperature treshold (80C ?) and what is the audible tone sequence to inform the user of this state ?

2) What is the over current limiter setting and why we cannot set it like with the XLX? it seems to be around 150/160 amps continuous (for at leat 4 seconds), because I can't get above this max value and the KV of the 1515, which is at 2220rpm/V no load, drops to 1700rpm/V which is a big difference with only about 5 mohms phase resistance (with turnigy graphene 10Ah 25C continous discharge measured with wayne giles IR meter V2) see graph below.

Thx !

Full size link: http://maxime.pierron79.free.fr/maxpowertest.png
1. 120C is the preset shutdown temp.
2. The overcurrent is set to around 400A initially, and drops with temperature. But I have to explain that the "logged" current is an average, and the "limiting" current is a peak -- so they may differ considerably.

Thanks!

Patrick


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maxxximatoze
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09.13.2018, 05:21 AM

Quote:
Originally Posted by Pdelcast View Post
1. 120C is the preset shutdown temp.
2. The overcurrent is set to around 400A initially, and drops with temperature. But I have to explain that the "logged" current is an average, and the "limiting" current is a peak -- so they may differ considerably.

Thanks!

Patrick
The 400A peak limit is for the manba monster X ? it's seems te be a huge value for such a small ESC ! How can it copes with such high current, only for a little fraction of a second I suppose ?

What is the max continous current for say 10 to 20 seconds that the MMX can support without risk, and with this fan instead of the original https://www.digikey.com/products/en?...2VHN-F00&v=603 ?
   
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09.13.2018, 01:31 PM

Quote:
Originally Posted by maxxximatoze View Post
The 400A peak limit is for the manba monster X ? it's seems te be a huge value for such a small ESC ! How can it copes with such high current, only for a little fraction of a second I suppose ?

What is the max continous current for say 10 to 20 seconds that the MMX can support without risk, and with this fan instead of the original https://www.digikey.com/products/en?...2VHN-F00&v=603 ?
Over 200A for 20 seconds.

And yeah, it's a pretty big value, but yes, it's for a very short time. The actual current where damage happens to the MOSFETs due to real damage to the die is over 600A.


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maxxximatoze
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09.14.2018, 03:41 AM

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Originally Posted by Pdelcast View Post
Over 200A for 20 seconds.

And yeah, it's a pretty big value, but yes, it's for a very short time. The actual current where damage happens to the MOSFETs due to real damage to the die is over 600A.
Ok so, to summuarize, as long as you can keep the mosfet temperature below for say 70 to 80C, you can pull as much current on 6S as with the XLX for example but due to the small physical size of the MMX, and in particular it's little heatsink, it's much harder to keep it cool, even with big air flow fan like a FFB0412VHN fan.

But, 200Amps continuous WOT without current limitation for less than 20 seconds (with 400Amps peaks due to the current limiter) on 6S with a very good air flow, a big cap pack and good reliability is possible, to do some speed run without going into flames for example :) The XXL is usually prefered for with but it is heavy and really big !

How much contiuous current the MMX survive at partial throttle as it does not has the active freewheeling software feature ?

If the MMX would be watercooled, what would be the maximum continuous current WOT can be sustained indefinitly ?

Like you said here https://www.rc-monster.com/forum/sho...59&postcount=5 monster X uses NEW MOSFET from Toshiba, fast switching, ultra-low RDSon (770 microohms typical), and at time of writing, the new toshiba mosfet line (released November 04, 2014) was U-MOS IX (see https://www.businesswire.com/news/ho...FET-U-MOS-IX-H and https://toshiba.semicon-storage.com/...ets_201601.pdf) and so at that time the only U-MOS IX mosfet available was 40V ref (TPHR8504PL and TPWR8004PL sub mirco ohm), the 30V ref was not available at tis time (TPHR6503PL available 11/2015) and so 8S is possible with 40V ref ! And like you said in another post somewhere in this forum, there is only one revision of the MMX so... :) Am I Right ?

Last edited by maxxximatoze; 09.14.2018 at 08:04 AM.
   
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