Have tech questions? Will answer.

[Voodoobrew]

Originally Posted by brian.brigg

Does the direction of rotation, forward or reverse, have any effect on skewed armature motors?

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It shouldn't, if the motor is going in reverse the other end breaks the field first is all. But that's just a guess.

[brian.brigg]

I think you are probably right. All the skewed armatures I've seen are skewed clockwise and I just got to wondering why.

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[JohnRobHolmes]

Originally Posted by brian.brigg

Hi John, thanks for the replies, it gives me a better idea of the difference between the Magnums and "standard" Crawlmaster motors.

One other question I put out a few months back that didn't get answered concerned stand-up versus lay-down brush styles. Stand-up would have slightly less "dwell" and overlap, particularly on 5 pole motors compared to lay-down, how does this affect motor performance and start-up?

Which style gives more back EMF and how does back EMF affect motor performance? How do ESCs handle back EMF? Does it have any useful effect on drag brakes?

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Lay down is not compatible with 5 slot commutators we use. Too much overlap.

Bemf is not changed technically, it just affects duty cycle of each coil. The motor will make a little more power, it has the potential for a shade more drag although I’ve never found it enough to notice.

Originally Posted by brian.brigg

Does the direction of rotation, forward or reverse, have any effect on skewed armature motors?

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If the arm is built properly the direction of rotation doesn’t matter. I own all the skewing tooling and have specified both the angle and direction of skew for each type.

[Voodoobrew]

I saw a post from like 10 years ago where you were running 6s on a high turn brushed motor. Is the big concern just brush wear and max rpm balancing or is there more to it than that. I can see from a manufacture point of view why you wouldent recomend it to the masses. But if I'm not concerned about longevity and want to run 6s on an 11000kv vs 3s on a 22000kv what should I expect? Just out of curiosity.

[JohnRobHolmes]

On brushed motors the issue becomes brush ablation, since we use brushes that are designed for 12v they literally explode apart slowly at 24v. A tapered brush leading edge or round brushes can help without going to lower copper content brushes. Even 55t motors on 6s make some crazy sparks on the brushes.


On brushless systems, it would net a cooler running controller and slightly higher torque density to use half the KV on twice the voltage.


6s batteries are generally much taller and don't give the rig as low of a CG as running 3s. If a controller isn't overheating and torque isn't lacking, going to 6s is mostly just going to make the CG higher and won't net a performance gain in practice.

[whitrzac]

Building a trail rig around a 2s/brushed motor requirement. Building it light, no added weight and hoping for <7lbs.
Every other rig I have is 3s and brushless. I had a couple that I ran 55t on, but no other brushed stuff.

What's your recommendation on crawlmaster vs torquemaster? Leaning towards the 13t crawlmaster pro right now...

[Browneye]

Originally Posted by whitrzac

Building a trail rig around a 2s/brushed motor requirement. Building it light, no added weight and hoping for <7lbs.
Every other rig I have is 3s and brushless. I had a couple that I ran 55t on, but no other brushed stuff.

What's your recommendation on crawlmaster vs torquemaster? Leaning towards the 13t crawlmaster pro right now...

I just installed a Crawlmaster Expert in a TRX4 Sport chassis - real nice and smooth. I would like to drop a couple of pinion teeth on it though.

Everything I have runs on 3S, 27, 35, and 45 turn motors, all with a HW1080. The faster motors I tend to gear down a bit, quite a bit on the 27T.



My heaviest rig is about 7.5lbs, the rest are sub-7. I don't do hard bodies or a bunch of scale detailing - opting for best rock crawling capability. All the weight goes in the axles.

[JohnRobHolmes]

13t crawlmaster pro would be a great choice.

[brimdogg]

Does anyone know the BEC amp rating of the BLE?
Thanks!

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[whitrzac]

Originally Posted by brimdogg

Does anyone know the BEC amp rating of the BLE?
Thanks!

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Same as the MMP


Maybe 2-3amps.

[Voodoobrew]

Has any one made a 6pole motor with 4 magnets and 4 brushes? So you could energize 2 coils at once.

I am pretty sure it is possible but how would it effect performance?




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[SnoopyBG]

I recently saw one of John's videos in which he said not to get a slower motor expecting more torque or low speed control. I then want to ask what high turn count motors are for then? Why would anyone prefer a 20T Crawlmaster to a 11T?

[JohnRobHolmes]

Originally Posted by Voodoobrew

Has any one made a 6pole motor with 4 magnets and 4 brushes? So you could energize 2 coils at once.

I am pretty sure it is possible but how would it effect performance?




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A 6 slot 4 mag would be possible, but it has construction that make it a less power dense motor than 12 slot. It is also the basis of concentrated vs distributed coil theory, and single layer vs double layer winding theory. It would typically have a higher detent force and would be very hard to tune with good startup. Same thing goes for 9-6 and 18-6. The lower slot count stator is typically only chosen when cost is the largest deciding factor, as it is cheaper to wind.

Originally Posted by SnoopyBG

I recently saw one of John's videos in which he said not to get a slower motor expecting more torque or low speed control. I then want to ask what high turn count motors are for then? Why would anyone prefer a 20T Crawlmaster to a 11T?

That is the case that slower motors do not provide better torque or startup speed - As long as we are within the "good" range of motor construction. If we threw a 9t crawlmaster into the mix, we could say that the 11t makes better torque with better low speed control. That is also why I don't make 5 slot faster than 11t and 3 slot faster than 27t. Low speed control and torque will suffer.

The turn of a motor should be matched to the needs of the user, the voltage, the gearing, the tire height. Some people want 20t speed. Some people want 11t speed. I like 13t speed. The most popular Crawlmaster wind jumps between 13t and 16t, but is normally 13t. Because of the Enduro being released with a 16t five slot, I can guess that the 16t will be more popular than 13t in the following months.

[351Beno]

Originally Posted by SnoopyBG

I recently saw one of John's videos in which he said not to get a slower motor expecting more torque or low speed control. I then want to ask what high turn count motors are for then? Why would anyone prefer a 20T Crawlmaster to a 11T?

Its all personal preference. Maybe you have a truck that's geared down as low as you can but all you have is 3s batteries the 11t maybe to fast or the 20t maybe better for that because of heat issues. Every rc is a little different but they all have limits. Best if your not sure is to ask what other use for Batteries, gears , tire size, and motor turns in the same truck.

[Voodoobrew]

Originally Posted by SnoopyBG

I recently saw one of John's videos in which he said not to get a slower motor expecting more torque or low speed control. I then want to ask what high turn count motors are for then? Why would anyone prefer a 20T Crawlmaster to a 11T?

I would say If you can't gear down any more and you want to go slow, and your already only running 2s on a 27t motor. But your slow speed lacks torque.

you could drop to a 65t motor and double the voltage. On 4s a 65t will be close to the same speed but have more torque, also the brushes won't last as long.

Gearing down I think is a better option though.

[JohnRobHolmes]

Gearing down is always the best option!


Changing voltage does throw a wrench into it. Higher turn motors ran on high voltage do tend to have slightly better torque output due to reduced copper losses ( and reduced brush losses if brushed).

[JohnRobHolmes]

Originally Posted by 351Beno

Its all personal preference. Maybe you have a truck that's geared down as low as you can but all you have is 3s batteries the 11t maybe to fast or the 20t maybe better for that because of heat issues. Every rc is a little different but they all have limits. Best if your not sure is to ask what other use for Batteries, gears , tire size, and motor turns in the same truck.

Exactly!

[Lil_Chop19922]

I'm looking at building a 6x6 on 3.8 swampers (already have them) and wraith axles. I'm figuring this thing will end up weighing alot (>20lbs) my only experience is a redcat everest 10 that I've put a eBay special brushless and esc on. So I'm a boob when it comes to the electrical side.
I'm planning on a servo winch and lights but my biggest thong is that I have no idea all the electrical components I'm gonna need.
Also looking on suggestions for motor and esc and any other controller I might need. I'd like it to be able to at least get up to well above walking pace and plan to run a 2 speed transmission.
Thanks for any advise

[JohnRobHolmes]

Have a budget? Brushless is nice but high cost compared to a sealed can brushed setup. You will want pretty slow, like 1000kv to 1500kv range running on 3s.

[Lil_Chop19922]

Originally Posted by JohnRobHolmes

Have a budget? Brushless is nice but high cost compared to a sealed can brushed setup. You will want pretty slow, like 1000kv to 1500kv range running on 3s.

Currently just getting a parts list together. I'd rather buy once cry once than keeping band aiding problems. Still probably a few months out on getting started just want to make the best decisions when I start ordering.