• Welcome to RCCrawler Forums.

    It looks like you're enjoying RCCrawler's Forums but haven't created an account yet. Why not take a minute to register for your own free account now? As a member you get free access to all of our forums and posts plus the ability to post your own messages, communicate directly with other members, and much more. Register now!

    Already a member? Login at the top of this page to stop seeing this message.

Have tech questions? Will answer.

Thinking of getting a 550 can trailmaster sport for my Wraith, but not sure of resulting speed with either 21t or 27t one.

Now I'm running a cheapo rebuildable GoolRC 35t geared as low as possible (9/56 with UD rear) and I could use more torque/smoothness/control on the low end. I'd like more top speed too but that's secondary.

How would a crappy 35t 540 compare to the trailmaster sport 550s?
 
World of difference, the magnets and brushes I use are much better for starters. Going to a 550 will give a lot more overhead of torque. The 27t will be about the same speed as your 35t, so get a 21t 550 if you want more speed.
 
I've got 3 of the Trailmaster Sport 550's now, including one in a Wraith. I found that there is more room to gear the 27t up if you find it too slow, than there is to gear the 21t down if you find it too fast. The 27t should be happier on 4s too (though I usually only run 3s), which makes top speed similar to the 21t on 3s, but with more bottom end.
 
Can your TorqueMaster Pro motors be run on 4S without shredding the brushes? I realize it's amperage that shreds brushes, not voltage, but higher voltage can push higher amperage, and also makes sparking more likely.
 
Mostly due to the switching frequency of the ESC, secondarily how good the motor is at being a speaker. 8k is the typical frequency and our ears are very sensitive to it. My quiet mode on the BRXL pushes the frequency to 18k, out of the audible range.
 
A couple of dumb questions...

1) If I want to do motor connectors, XT30 or XT60? I know the difference is what they can handle, but I like the 30 for the smaller foot print.

2) is 14 gauge silicone wire okay for a motor? The wire on my motor is 18 (I think) and has stiff insulation, thus making the motor connections a little fragile.
 
JohnRobHolmes said:
Mostly due to the switching frequency of the ESC, secondarily how good the motor is at being a speaker. 8k is the typical frequency and our ears are very sensitive to it. My quiet mode on the BRXL pushes the frequency to 18k, out of the audible range.
Click to expand...

Ah yes, I may have switched the frequency on the HW1080. I'll look at that again.
Very interesting!

Motor is a Trailmaster 540 35T in that one.

On wiring and connections, everything I have is 14ga with Deans. I use crimp connectors and shrink-wrap for motorwire to ESC connection, or heat-shrink type connectors. If/when a motor change is necessary just cut them off.

Just never an issue with wiring - it all works fine.



 
Last edited:
JohnRobHolmes said:
Mostly due to the switching frequency of the ESC, secondarily how good the motor is at being a speaker. 8k is the typical frequency and our ears are very sensitive to it. My quiet mode on the BRXL pushes the frequency to 18k, out of the audible range.
Click to expand...
The HobbyWing WP1080 has an adjustable PWM frequency, from 1kHz to 16kHz. 16kHz is completely inaudible to me now, and I'm only 35. However, after experimenting, I discovered that 1kHz produces the same sound as the Dynamite and Axial rebrands of older HobbyWing ESCs. At that pitch, it's not an offensive sound to me (roughly the same pitch as a female voice, and it's not nagging at me ;-)), and it's also the setting that produces the least waste-heat, so I just go with 1kHz. If I couldn't stand the PWM sound, I'd go with 16kHz and maybe install a quiet fan on the ESC to prevent the possibility of overheating.

The human ear is most sensitive to ~4kHz, because that's the resonant frequency of the ear canal (https://en.wikipedia.org/wiki/Equal-loudness_contour#Experimental_determination), which is why train horns (and those obnoxious aftermarket car horns, which are only ever purchased by people who *like* using the horn) are tuned to that frequency range. My ears can hear 8kHz clearly, but it's not painful like 4kHz is.
 
Last edited:
^^^ I love reading technical info like you posted - educates me on how to program my electronics to suit my situation correctly!

Muchly appreciated, sir!

Too many companies write their manuals without giving a human touch to what each setting can change for the end user.

I'm in IT, but not knowledgeable on certain aspects of ALL technologies - no one is!

There's just too much stuff to keep track of these days...
 
Last edited:
Well, I have to give HobbyWing credit for explaining that the lower PWM settings reduce the amount of waste-heat. I guess it doesn't surprise me now that I know about it. The switching is never instantaneous, so switching more often means the transistors are in a stable state for less time per second, so they have to handle more wattage during that reduced time to allow the same wattage to reach the motor. However, I wouldn't have thought of it without the manual mentioning it to me first.

The audible sound I managed to figure out on my own, though. ;-)
 
I called it "higher switching losses" instead of "more waste heat". Looks like I could learn a thing or two about dumbing down english from hobbywing, lol!
 
Judging by the quality of the English, I'm guessing it was dumbed-down in the original Chinese prior to translation. But I agree, "higher switching losses" doesn't make it instantly obvious to the casual user why they should care, or how to notice if the "switching losses" are dangerously high.
 
I've read JRH talking about the BLE having the adjustable frequency to run in quiet mode, I just wish that it was being used in the newer CC X-Series Mamba ESC with the Auxiliary Wire functionality.

Trying to have the best of both worlds, as it were... ;)

My HW 1080 with the HH Trailmaster 550 is pretty damn quiet, and I know my Revolver-equipped RR10-based rig will be a noisy beast when done - but with a GMC Topkick body I'm going to pretend it's a diesel, as that's how the power delivery of the loud outrunner has been described anyway.

The ESC for it is a Mamba X, 4S power.

However, I'm hoping to keep my other upcoming RR10 build a little quieter - it's got a Mamba Monster X with a HH PP 4100kv R-type motor, 3S with a nice quiet SHV500 servo.

I'm going to turn all the audible alarms off in programming for both, and see what else I can find in the settings.....
 
1 kHz is the test tone (bleep) that goes together with color bars (which we used to see on TV but are now more likely to see and hear in video intros and such). :)
I keep my 1080 at 16kHz, I can still hear that but don't really notice it when driving. 18 kHz is pretty much out of range for my aging earholes.
 
You must log in or register to reply here.

Similar threads

HumboldtEF
HumboldtEF's 4WS Portal H10 Optic
Replies
0
Views
146
HumboldtEF
HumboldtEF
R
Choosing a platform for my first RECON G6
2
Replies
23
Views
3K
Reezo
R
T
WE RC ROCK Rules 2024
Replies
1
Views
2K
cooper_xl
cooper_xl
T
Wraith 1.9 FPV
Replies
2
Views
96
tuxstang
T
I
Best option for 1st time competetive Rock Crawler on a budget
Replies
18
Views
3K
IronArcher
I
Back
Top