RCCrawler Forums

ntm · 10-27-2008, 10:01 PM

Quote:

Originally Posted by JohnRobHolmes

No it would not. The startup jerk is because the poles have high attraction to the magnets, it is a function of the slot/magnet ratio. It takes some force to get the motor spinning basically. I am working on a different design right now. It may end up being an inrunner, but a high pole count inrunner to have much higher torque at low speeds as compared to currently available sensored inrunners.

The high pole count inrunners I've worked with are just as "notchy" as the outrunners of a similar diameter. Actually the outrunners might have been smoother.
Sounds like you need a smaller version of the kontronik "tango" series, they spin freely. They're very effecient with no ferrous losses.
Unfortunately they're only produced in 45mm diameters.

The roughness your experiencing wouldn't be caused by the rather large magnetic flux a 3 phase motor experiences on startup, would it ?
It should certainly be enough to skew your pickups signal, I would think.
Optical pickups would be ideal.

Just throwing some ideas out there, interesting stuff though, you could corner the market as far as crawler powerplants go, with a sensored outrunner. Nice work

Regards,
Nathan

JohnRobHolmes · 10-28-2008, 07:10 AM

Quote:

Originally Posted by miniwheeler

How about a stator built with some twist in it instead of the poles lined up in straight lines

This would fix the pole/ magnet attraction.

The slot to magnet ratio is the culprit of the notchy starts. There are three fixes. Skew the stator, change the construction (magnet/pole ratio), or make the motor slotless.

SlickRockSpider · 10-28-2008, 10:15 AM

Quote:

Originally Posted by ntm

Sounds like you need a smaller version of the kontronik "tango" series, they spin freely. They're very effecient with no ferrous losses.
Unfortunately they're only produced in 45mm diameters.

I take it you have experience with a "tango". I looked on there web site and did not see "no ferrous losses". If you have more info PM me. I would like to know.

Evan

Karadjas · 10-30-2008, 05:55 PM

So no need to "volt up, gear down" as much with a sensored outrunner then I guess... My KMS 980kv outrunner is doing great with 10 cells and ~35:1 in a 2.2.... Good enough to keep the cobalt 6ts in the electronics drawer. I guess I'm "special", in terms of liking outrunners more than cobalts heh

zoojunkie · 10-30-2008, 07:43 PM

Nope, I like my little 1050kV outrunner more than a 55T. I'm looking at a bigger one for the future

Jeepial · 11-02-2008, 04:26 AM

Wanna hook up my Crawlmaster so I can use it again? lol

4xFord · 02-09-2009, 07:29 PM

Bump, what tha dilly yo?

JohnRobHolmes · 02-10-2009, 05:42 AM

Still working on it, I have a few designs I am working with but nothing ready for mass production yet.

MKDU2 · 04-20-2009, 12:02 PM

Bump, any updated info yet ???

JohnRobHolmes · 04-20-2009, 02:05 PM

Not yet, waiting on some prototypes. The initial design has been chosen however.

hitman46mod · 04-20-2009, 04:16 PM

I would go back to brushless if it works. I tried a crawlmaster sport 3014 1000kv but was unhappy about about the lack of lowspeed resolution and the cogging on startup.

JohnRobHolmes · 04-20-2009, 04:17 PM

That is why I went back to brushed. Then I got tired of cutting comms so I started working on this motor

megacabcummins · 04-21-2009, 06:10 AM

Do you have any time frame as to when this might come out? I was thinking of running the 21.5 Losi sensored motor and ESC once my comp crawler gets here, but if I could get an outrunner instead that would be sweet. Just not sure though if it would give me enough wheel speed with those worm drives...

JohnRobHolmes · 04-21-2009, 09:08 AM

It will be awhile. Probably another few weeks till I get the proto and then 6 weeks for the first run. The hard part will be finding an ESC at the same time at a good price. There are a few companies that make sensored ESCs, but so far all have some little bug or another.

The CrAwLL BLACK · 06-06-2009, 05:09 AM

Hi JRH,

These things sound great. I'll definately be keen on getting me some of these when they come out.

Cheers,
Mike.

JohnRobHolmes · 06-06-2009, 07:04 AM

I have it worked out that I will have combos for the system too. prototype still isn't done yet, but should be very soon.

mattnin · 06-07-2009, 09:54 PM

Is the prototype an inrunner or outrunner type brushless motor?

JohnRobHolmes · 06-07-2009, 10:25 PM

outrunner. Inrunners are easy to find these days.

jafa0 · 06-07-2009, 11:05 PM

Very very cool. this should be THE hot ticket for the Losi CC. Once you get this ironed out I want one bad..

mattnin · 06-08-2009, 09:31 AM

Sounds very good JRH! I am very interested in a small lightweight outrunner sensored motor!

LinkBacks (?) LinkBack to this Thread: http://www.rccrawler.com/forum/electronics/136315-sensored-outrunner-motors-revolver-s.html
Posted By	For	Type	Date
Outrunner for rock crawler - Kv and low-speed smoothness, is my theory sound? - RC Groups	This thread	Refback	10-07-2011 12:03 AM

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10-30-2008, 05:55 PM	#64
Karadjas Quarry Creeper Join Date: Jan 2008 Location: Cyprus Posts: 321	So no need to "volt up, gear down" as much with a sensored outrunner then I guess... My KMS 980kv outrunner is doing great with 10 cells and ~35:1 in a 2.2.... Good enough to keep the cobalt 6ts in the electronics drawer. I guess I'm "special", in terms of liking outrunners more than cobalts heh

10-30-2008, 07:43 PM	#65
zoojunkie Quarry Creeper Join Date: Jul 2008 Location: Over a rock and under a bridge Posts: 221	Nope, I like my little 1050kV outrunner more than a 55T. I'm looking at a bigger one for the future

11-02-2008, 04:26 AM	#66
Jeepial I wanna be Dave Join Date: Sep 2008 Location: behind the wheel of a monster truck... Posts: 2,878	Wanna hook up my Crawlmaster so I can use it again? lol

02-09-2009, 07:29 PM	#67
4xFord I wanna be Dave Join Date: Oct 2007 Location: Houston Posts: 3,761	Bump, what tha dilly yo?

02-10-2009, 05:42 AM	#68
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	Still working on it, I have a few designs I am working with but nothing ready for mass production yet.

04-20-2009, 12:02 PM	#69
MKDU2 Newbie Join Date: Jan 2008 Location: State College Posts: 28	Bump, any updated info yet ???

04-20-2009, 02:05 PM	#70
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	Not yet, waiting on some prototypes. The initial design has been chosen however.

04-20-2009, 04:16 PM	#71
hitman46mod RCC Addict Join Date: Sep 2007 Location: Westland, MI Posts: 1,508	I would go back to brushless if it works. I tried a crawlmaster sport 3014 1000kv but was unhappy about about the lack of lowspeed resolution and the cogging on startup.

04-20-2009, 04:17 PM	#72
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	That is why I went back to brushed. Then I got tired of cutting comms so I started working on this motor

04-21-2009, 06:10 AM	#73
megacabcummins Quarry Creeper Join Date: Oct 2008 Location: Marysville Posts: 452	Do you have any time frame as to when this might come out? I was thinking of running the 21.5 Losi sensored motor and ESC once my comp crawler gets here, but if I could get an outrunner instead that would be sweet. Just not sure though if it would give me enough wheel speed with those worm drives...

Sponsored Links

04-21-2009, 09:08 AM	#74
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	It will be awhile. Probably another few weeks till I get the proto and then 6 weeks for the first run. The hard part will be finding an ESC at the same time at a good price. There are a few companies that make sensored ESCs, but so far all have some little bug or another.

06-06-2009, 05:09 AM	#75
The CrAwLL BLACK Rock Crawler Join Date: Jan 2009 Location: Christchurch, New Zealand Posts: 501	Hi JRH, These things sound great. I'll definately be keen on getting me some of these when they come out. Cheers, Mike.

06-06-2009, 07:04 AM	#76
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	I have it worked out that I will have combos for the system too. prototype still isn't done yet, but should be very soon.

06-07-2009, 09:54 PM	#77
mattnin Rock Stacker Join Date: Feb 2006 Location: Grand Junction Posts: 91	Is the prototype an inrunner or outrunner type brushless motor?

06-07-2009, 10:25 PM	#78
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	outrunner. Inrunners are easy to find these days.

06-07-2009, 11:05 PM	#79
jafa0 Rock Stacker Join Date: Oct 2008 Location: Tualatin Posts: 53	Very very cool. this should be THE hot ticket for the Losi CC. Once you get this ironed out I want one bad..

06-08-2009, 09:31 AM	#80
mattnin Rock Stacker Join Date: Feb 2006 Location: Grand Junction Posts: 91	Sounds very good JRH! I am very interested in a small lightweight outrunner sensored motor!

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