Brushed Motor Slot Comparison???

[Boing]

Hi Everybody, **Hi Dr. Nick**

I was curious if there has ever been a "same turn comparison" of brushed motor Slots???

I understand the differences between lets say a 3-slot vs a 5-slot and what it means. I've also heard that a "fair" comparison is between a 27T 3-slot and a 13T 5-slot. But that's where I start to wonder... Does that mean a 13T 5-slot is or will perform roughly the same as a 27T 3-slot???

That is why I'm curious to see a same turn comparison between a 3-slot and 5-slot brushed motors. Take two 20T motors (one 3-slot, one 5-slot), then put them in the same exact RC, both having the exact same gearing, wheel and tire set-up... What is the real difference made by the amount of slots???

[brimdogg]

Check out Holmes Hobbies website, it has a good comparison sheet. I can't remember exactly what the differences are either LOL

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[HumboldtEF]

I found it a bit easier to think of in terms of KV ratings, which I know is more of a brushless thing but its a speed rating rather than this sort of confusing turn count plus the number of slots conversion/guessing game. I've sat down and tried to figure out if there was a formula for converting 3-5 slots in terms of how many turns but every time I try I fail. So KV ratings have been a good alternative for me.

I was also just studying up on the HH motor comparison chart and its pretty helpful in getting a general idea of the speed.

https://holmeshobbies.com/motor-recommendations

Beyond just the speed the general rule is that a lower turn 5 slot motor will have a smoother start up than a higher turn 3 slot motor given the same gearing.

I just tested out this scenario on my Venture comparing a 20T 5 slot to a 45T 3 slot and while I like the slow general speed of the 45T I did prefer the smoothness down low that the 5 slot offered, both geared the same. I've always preferred the 5 slot Crawlmasters but had never done this kind of comparison myself.

[mikemcE]

Hang up and Drive

[HumboldtEF]

That pic is either older or its cutting off the bottom of the page.

[Voodoobrew]

Performance is a poor word choice because it is very general. Terms like torque, power, speed, smoothness being more specific might help to guide us in what's important for you and what to recomend.

I think first thing is you need to let us know what motor your currently using, what pinion/spur you have, what rig it's in, what batteries you use.
Then decide how fast you want to go compared to your current speed with some sort of measurable amount such as in 50% faster, or in mph.
Then whether or not you want more low end torque or you're happy with what you have.

Personally I'm pretty much alwayse going to recomend 3s batteries, a trailmaster 21t 550, and gearing down to the speed your happy with myself. Because that motor has a ton of torque and power for $20 and in an axial rig with a 3 gear transmission which is pretty common it costs about $15 to gear down to 100:1 (stock is like 35:1) so right there is like 300% more torque, 1/3 slower minimum speed and low end usability in general which is great for crawling.

After gearing this low the difference between a 3 and 5 slot is hardly noticeable by me except for the difference in turn count.

To me the real downside to a brushed motor vs brushless is the lower maximum rpm. A lower initial start speed of a brushed motor is also not as noticeable at lower gear ratios but with the higher max rpms of a brushless motor you can keep a higher top speed with torque to spare.

I know this dosen't really answer the op, but in my opinion it negates the question as in my experience I don't notice much difference between a $20 3-slot 21t trailmaster and an $80 5-slot 10t crawlmaster. Certantly not 4x anything except for price, but only slightly better, and of course it's rebuild able.

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[Jay-Em]

I cannot give a complete list of comparisons, but I recently got me a 20t Surpass5-slot to replace the stock 35t RC4WD in my MST CMX.

After a bit of running, I’m won for 5-slot motors. They can creeeeep... Just for a test, I ran up&down the stairs next to my parking. My usual “test” . And the power comes in soo smooth.. yet, if You hammer the throttle, it just wheelies up the stairs sheesh.. not exactly what I expected tbh. It gets plenty wheelspeed, even on 2s.

In general, the speed with the 20t 5-slot is a bit slower than the 35t, but not by much. When giving the 20t 5-slot a 23t pinion, its speed is afa I can tell, was about the same as the 35t stock with a 20t pinion. But the 20t 5-slot is way smoother in the lower rpm range, yet it can still put down the power quite impressively when hammering the throttle.

On the other hand, I put a 17.5 t sensored brushless in my Bruiser, and that works remarkably well, smooth and all.

In the end, I don’t feel there’s a lot of difference afa power and controllability goes between a 5-slot brushed, and a sensored brushless, lower Kv motor. Biggest advantages of brushless: no brushes to wear. Higher efficiëncy, leading to less heat and longer battery life ( with the correct gearing, of course)

Well.. that’s just my $0.02 after fiddling a bit with a 5-pole brushed.

Now all that’s left to test is the 16t, the 13t and the 11t ( bought me one of every wind Surpass offers in the 5-pole range)

[soze]

Originally Posted by Jay-Em

I cannot give a complete list of comparisons, but I recently got me a 20t Surpass5-slot to replace the stock 35t RC4WD in my MST CMX.

After a bit of running, I’m won for 5-slot motors. They can creeeeep... Just for a test, I ran up&down the stairs next to my parking. My usual “test” . And the power comes in soo smooth.. yet, if You hammer the throttle, it just wheelies up the stairs sheesh.. not exactly what I expected tbh. It gets plenty wheelspeed, even on 2s.

In general, the speed with the 20t 5-slot is a bit slower than the 35t, but not by much. When giving the 20t 5-slot a 23t pinion, its speed is afa I can tell, was about the same as the 35t stock with a 20t pinion. But the 20t 5-slot is way smoother in the lower rpm range, yet it can still put down the power quite impressively when hammering the throttle.

On the other hand, I put a 17.5 t sensored brushless in my Bruiser, and that works remarkably well, smooth and all.

In the end, I don’t feel there’s a lot of difference afa power and controllability goes between a 5-slot brushed, and a sensored brushless, lower Kv motor. Biggest advantages of brushless: no brushes to wear. Higher efficiëncy, leading to less heat and longer battery life ( with the correct gearing, of course)

Well.. that’s just my $0.02 after fiddling a bit with a 5-pole brushed.

Now all that’s left to test is the 16t, the 13t and the 11t ( bought me one of every wind Surpass offers in the 5-pole range)

Chances are they're the same motors as the Yeah Racing 5-slots,etc.

Any idea if the surpass ones are 3S capable? Yeah Racing states theirs as 2S capable but no mention of 3S.

[Jay-Em]

Surpass also mentions 8.4v max. So I guess 3s is not an option. Though, for the money ( I paid about $13.- a piece) it could be a worthy experiment. Imho there’s nothing in a bit higher voltage, that cannot be fixed by correct gearing.

And, Yes. The motors look suspiciously like the Yeah-Racing offerings imho. Specs are also ‘suspiciously’ close :P

[TheLetterJ]

I've got a pair of the Yeah Racing 16t 5 slots in my MOA and will be running them on 3 and 4s as soon as my batteries get here. I don't anticipate them bursting into flames.

I don't know if it actually pencils out, but I've just guesstimated the 3 slot to 5 slot speed comparisons like so: 16t x 5 slots = 80 turns, divide those 80 turns by 3 slots and you get roughly 27. By the same calculation, a 13t 5slot = 22t 3 slot, 20t 5 slot = 33t 3 slot, etc. Now I know that in actuality, the 5 slots are a bit slower than that still, but it's helped me for comparisons sake.

I know that the 5 slots make less peak wattage than a comparable speed 3 slot, but I'm hoping to overcome that by feeding them more voltage.

[Voodoobrew]

But why are you guessing at math when holmes made that easy to use table?

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[TheLetterJ]

Why guess? First, I see no math on that chart, so while that chart applies to his motors, it doesn't necessarily match other manufactures motors, depending on other variables of the motor build. What if brand "Y" uses a different wire diameter than brand "X", or different magnets, or brushes, or ??? Sure it is close enough to approximate (which is all I was suggesting with my "ballpark" method), but what if you want to know how a motor NOT listed on the HH chart compares? Having a basic formula to give you an idea is useful too. At the end of the day, all we're going to be able to do there is figure out KV (which is useful) but it doesn't give us any idea of what power output, curves, and feel are like.

That said, I've got 6 or 7 cars running HH motors, so I clearly trust Mr. Holmes' information/chart, I'm just thinking that there's got to be a simple formula for comparing apples and oranges so everyone can solve for themselves without having to be spoon fed an answer everytime.

[JohnRobHolmes]

There is no simple formula unless we constrain everything and then only specify two lamination designs. And the theory won't quite match the real world results, so we would basically have to work backwards from real world data to derive a best fit formula.


Buuuuut, we can assume that a five slot motor is about half the speed of the same turn 3 slot. That is making a lot of assumptions and does not hold up when comparing motors with different build, but it's a pretty good ballpark when the company give you no information to go from.

[JohnRobHolmes]

Have fun smoking that 11t machine wound. I can guarantee they didn't test it and just copied my Crawlmaster Pro turns without understanding the limits of spot welded 5 slots. Surpass even had their motors labeled as "Hobbies Crawlmaster Pro" motors until I pulled out the trademark. You vote with your dollars, I would implore people to not support companies like that because it directly hurts the companies that actually work to develop and support this hobby.

[JohnRobHolmes]

I'll just leave this here. I'm sure they will do it again soon once they think I'm not paying attention. Not just making a similar product, literally stealing multiple aspects of brand dress and trademarked name.

[durok]

Originally Posted by JohnRobHolmes

Have fun smoking that 11t machine wound. I can guarantee they didn't test it and just copied my Crawlmaster Pro turns without understanding the limits of spot welded 5 slots. Surpass even had their motors labeled as "Hobbies Crawlmaster Pro" motors until I pulled out the trademark. You vote with your dollars, I would implore people to not support companies like that because it directly hurts the companies that actually work to develop and support this hobby.

Originally Posted by JohnRobHolmes

I'll just leave this here. I'm sure they will do it again soon once they think I'm not paying attention. Not just making a similar product, literally stealing multiple aspects of brand dress and trademarked name.

Damn...

... NOT cool.

Not cool at ALL!

Between JX servos and these guys, I could only imagine your (totally justified) frustration level.

[svt923]

Originally Posted by JohnRobHolmes

Not just making a similar product, literally stealing multiple aspects of brand dress and trademarked name.

You buy our motor, Homes Hobbies CrawlerMaster Pro! Maximum #1 best power!

I can't imagine what is more frustrating; having these Chinese companies blatantly rip off your product or the small US companies that import said ripoff products then pretend they put actual development into "their" product.

[Jay-Em]

Huh. Tbh. Never noticed the peculiar likeness of the sticker to a HH. I just thought ‘cool. 5-slot. Lessee what they do’ But now You mention it..sheesh..

Just bought them because they were hella cheap, and wanted to experiment for a bit. I got more Surpass motors, they have been proven to be quite reliable in normal use. No fan of using 3s. I rarely use 3s apart from my speedboats and airboats. So, maybe I don’t push them enough to become troublesome.

Come to think of it, the 5-poles could be nice in a smallish yacht I have lying around. Precise control at low speeds is quite nice in model boats imho. Or 2 16t motors in my HL Leopard2a6... hmmm.. *mental gears churning*

Not going to try it now, though. It’s about 100degrees outside.. I rather stay inside in front of a fan.. :P

[Voodoobrew]

Originally Posted by svt923

You buy our motor, Homes Hobbies CrawlerMaster Pro! Maximum #1 best power!



I can't imagine what is more frustrating; having these Chinese companies blatantly rip off your product or the small US companies that import said ripoff products then pretend they put actual development into "their" product.

The cheap ripoff motors and the quality motors probably all come from the same factory. You design it send them the specs they make it and send it back. That's why you see stuff that looks so similar on the outside but is way different on the inside. The mfg probably has stock motors where you set parameters when you order them. Picking different quality materials, windings, spacing ect. Crawlmaster motors are pretty good, consumers are picking up on that. A new inexpensive 5 slot comes out, creates a bunch of talk, so a bunch of names order some. But they don't necessarily all order the same thing, one may have bushings, other bearings, one may have the discount copper wire ect. That's not really the same as stealing someone's design.

Mind I"m not saying designs aren't getting stolen. Or that anything you said is wrong.
I am just very cautious with accusations. I may be totaly wrong, I never ordered a ton of motors from china before, that's just how I assume it works. I am rather naive.

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[JohnRobHolmes]

I can assure you that the factories that are good at cheap are not the same ones that are good at quality. And so far all these Chinese rebuildables are testing the exact same regardless of vendor. Nobody is specing higher quality components. "High strength, high temperature high torque" means absolutely nothing, unfortunately. My sealed cans have higher grade magnets than these "high strength" rebuildables.