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Old 01-21-2007, 12:18 AM   #1
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Default difference in building style mamba / lrp

I noticed a funny difference between them two

one guy at the races said
"Oh my, look at the strenght of these magnets .." and tried to rotate the rotor ... it looked like a brushed motor or one with a grooved rotor even .. but my mamba does rotate freely, I CAN SPIN MY WHEELS LIKE THERE AIN`T (damn caps) a pinion gear in it at all .......


this means Castle doesn`t use any iron as a core material where lrp does ...

two questions

1 - is this why a castle esc. doesn`t run a lrp motor ??

2 - what would be the better way to go ??


with bonded a would say use a iron core because u will have more strength

BUT with sintered and bitter rotor diameters .. DON`T use iron core because u will have iron loses and eddy currents while there`s already strength enoough ...

so an iron core will only create more heat ...




what`s ure opinion ???
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Old 01-21-2007, 08:22 AM   #2
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All Mamba rotors are sintered and are cans are not slotted. The reason why the Mamba does not run LRP or Novak motors is because they are sensored and our motors are sensorless.

We have an update coming very soon that will allow the Mamba to run the Novak and LRP motors.

I would suggest the Mamba especially with our update coming that will allow you to basically run any motor on the market. Not to mention our programming via the USB cable is much easier then trying to stick program.

Later,
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Old 01-21-2007, 09:22 AM   #3
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relax buddy as i said i already own a 7700 set and it`s a blast !!!


but i guest it would a problem to run them because of this difference ... no software update would ever make it possible to use the sensor on the other motors ....
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Old 01-21-2007, 10:06 AM   #4
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Quote:
Originally Posted by CRASH
All Mamba rotors are sintered and are cans are not slotted. The reason why the Mamba does not run LRP or Novak motors is because they are sensored and our motors are sensorless.

We have an update coming very soon that will allow the Mamba to run the Novak and LRP motors.

I would suggest the Mamba especially with our update coming that will allow you to basically run any motor on the market. Not to mention our programming via the USB cable is much easier then trying to stick program.

Later,
Hey Crash,
When is this update your talking about coming out? Furthermore, which Mamba motor is equivelent to the Novak 4300 motor or a 19 turn brushed motor?
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Old 01-21-2007, 12:47 PM   #5
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when can mamba update the size of there esc? make it more compact. i saw one (i dont know if it was the new one since i dont know much of the new brushless esc mamba make and how many are those in the market ) but that esc he have on his car is so big..much bigger then the gtb.
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Old 01-21-2007, 03:11 PM   #6
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Quote:
Originally Posted by duhh
relax buddy as i said i already own a 7700 set and it`s a blast !!!
My bad, I just reread and you want to know which is better as far as sensored for sensorless.

Sensorless in my opinion is the best, but others will state sensored is. Sensored has more start up torque but is really only tuned for one certain rpm. Where sensorless has less start up torque but the motors timing is consatntly being adjusted by the speedo for max performance at all rpm levels.

Hope that helps,
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Old 01-21-2007, 03:13 PM   #7
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Quote:
Originally Posted by CHRIS CHAVEZ
Hey Crash,
When is this update your talking about coming out? Furthermore, which Mamba motor is equivelent to the Novak 4300 motor or a 19 turn brushed motor?
Should see the update fairly soon, next month or so. We do not currently have a motor comparable to the Novak 4300 or a brushed 19T. We are working on a motor that will be very similar to the Novak 4300 and a brushed 19T.

Later,
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Old 01-21-2007, 03:20 PM   #8
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Quote:
Originally Posted by CRASH
Should see the update fairly soon, next month or so. We do not currently have a motor comparable to the Novak 4300 or a brushed 19T. We are working on a motor that will be very similar to the Novak 4300 and a brushed 19T.

Later,
Thanks Crash
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Old 01-22-2007, 08:54 AM   #9
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pinggoy, where in WP are you? do you go to the Royal Palm track? Anyway, The size of the GTB is deceiving. I say that because Novak gives the case footprint size, but does not give the actual dimensions with the 2 PC boards sticking out the side. The Mamba and GTB are actually almost identical in size. I've had the GTB and sphere in the past, I prefered the sphere till bought a Mamba. It easily mounts in my TRF415 which is not the worst in terms of room, but not the best either. Try one, you wont be disappointed!
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Old 01-22-2007, 09:36 AM   #10
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The answers from Crash are interesting. I thought that the sensored motors and unsensored were basically the same, except for the sensors of course. But that would mean that sensorless ESC could run sensored motor, you would just leave the sensors disconnected.

I also thought that the sensors allowed for dynamic timing so sensored motors would always be perfectly timed (depending on ESC software) but with sensorless motors the ESC would always be guessing what the position of the armature/rotor is so the timing could be out of whack.

Crash, what exactly is the difference in the winding of sensored and sensorless motors? And how can the Mamba ESC be constantly optimising timing when it doesn't know the position of the rotor?

Duhh, I can spin my LRP 4.5 brushless sensored motors (sintered) rotor with ease.
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Old 01-22-2007, 09:55 AM   #11
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The Mamba Max ESC uses back EMF to monitor what the motor is doing. In some sense, it is almost as if the ESC is sensored. Basically, as long as the R&D that went into the ESC software is done right, you will have exceptional performance as is the case with the Mamba Max.
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Old 01-22-2007, 08:14 PM   #12
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Quote:
Originally Posted by andsetinn
Crash, what exactly is the difference in the winding of sensored and sensorless motors? And how can the Mamba ESC be constantly optimising timing when it doesn't know the position of the rotor?
The winding style is separate from the sensored or not. ROAR (Novak spec) requires wye wound which is harder for sensorless controllers to run. Wikipedia on DC Brushless for a comparison of winding types

Any sensorless controller needs to have some guess as where the rotor is for it to work. Saying a Mamba or other sensorless controller doesn't know is an exaggeration. Timing advance is simply how much in advance the windings are fired.

The LRP 'timing by moving the sensor' thing is a bit lame in that it could be done in software and the software could be smart about it.
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Old 01-23-2007, 03:28 AM   #13
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That wikipedia thingie doesn't tell me much I didn't already know. The brushless motors we´re using are really 3-phase AC motors.

I've connected literally hundreds of 3 phase AC motors to mains power or speed controllers. They're all connected in the same way and you can mix and match 3-phase AC motors from different manufacturers as you like.

I'm not sure what you mean by "The LRP 'timing by moving the sensor' thing". Timing and adjustments there-of are best done by the ESC software and you need sensors to get accurate position of the rotor. You could use current sensoring inside the ESC and monitoring voltage feedback through the wires (not in any way related to EMF (Electro-Magnetic Field) measuring) to adjust the timing but that is just guesswork. It may be right most of the time but it's still just guesswork. Having said that I believe that sensorless motors and ESCs will win in the end. Not least because they're significantly cheaper to make.
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Old 01-23-2007, 09:39 AM   #14
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Quote:
Originally Posted by wrxnfx
The Mamba Max ESC uses back EMF to monitor what the motor is doing. In some sense, it is almost as if the ESC is sensored. Basically, as long as the R&D that went into the ESC software is done right, you will have exceptional performance as is the case with the Mamba Max.
wrxnfx, Thanks, you are dead on with that statement.

Later,
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Old 01-23-2007, 10:13 AM   #15
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Thanks, Crash. Even though I've been into this hobby pretty hardcore for about 10 years, my uncle taught me a lot as he has some electronics & engineering background and used to race a lot way way back in the day. He thought he would never see the day that brushless motors would be so widely available at such reasonable prices. To add to that, that they work so well, too.

The unfortunate thing about my uncle is that he doesn't want to patent any of his ideas because he thinks it's too much trouble. If he had done so, he would be rich. Oh well, he doesn't care because all of his inventions and ideas were mainly to make life easier for himself and not to make money anyway.

To give you an idea, if any of you remember those Entertech motorized water guns from way way back. When I got one of those, my uncle told me that it was junk and said the ultimate water gun would use compressed air instead. He then constructed his own water cannon using a small air tank he bought at a swap meet for $5 and a few other parts. He never pursued to market it as he thought it would never sell because he couldn't figure out a way to make it look like a real gun. A few years later, the Super Soaker was released. I have so many more stories like this including how most 1/12th scale standard rear end suspensions today have flex in the chassis to provide more rear end traction, my uncle actually created this back when he was racing.

Last edited by wrxnfx; 01-23-2007 at 10:27 AM.
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