What’s In There! Understanding Brushless Motor Parts | Holmes Hobbies RC Basics Series

What’s In There! Understanding Brushless Motor Parts | Holmes Hobbies RC Basics Series


Have you ever looked at a brushless
motor and thought what’s inside if you have then you’re in luck because the day
I’m gonna talk about brushless motors and the parts that are inside I’m John
Holmes with Holmes hobbies and stay tuned today’s topic is brushless motors and
the parts that are inside and I figured the best way to show you what it is is
to take it apart and talk about it while I do so so let’s just get right into it
I’m gonna start today with a home table ease puller Pro 540 and this one is a
3500 kayvyun and it this one is a 4-pole we’ll check it out as we open it up so
every motor is gonna be slightly different and how it takes apart but for
the most part you’re gonna take off a face plate or an in bell or an end cap
or whatever you want to call it and then the motor guts can slide right out or at
least the ones that aren’t glued in if it’s gonna be a two-pole than more than
likely everything slides right out but the majority of motors in the market at
this point seem to be for pole and they tend to be glued together so I took out
three Phillips head screws on the end of this motor we usually call it the end
cap but sometimes the end belt just for congruence with our brush motors and
sometimes these parts can be a little fiddly to get off if you’re taking a
part of motor like the castle slate it’s actually glued into place and it’ll take
some heat to get it off or a really hard hit on some concrete which is not
recommended so you know hit it with some heat on ours we don’t quite go that
crazy so I can kind of you know take this with my fingernails and pry it off
or I can gently push it on a table until the end slides off just like that just a
little Boop alright so we have the end cap and we also have the sensor board on
this particular model not all motors are censored but a lot of them are because
it gives you a better low speed control on the majority of motors not exactly a
cut and dry situation but we’ll talk about it just like it is so here’s our
sensor board you can see these little three black sensors on there and then a
couple of smaller components maybe you can see those and those are going to be
smoothing so that they get a smooth 5 volt or 7
volt voltage to them and then the resistors that are typically on the
board are going to pull them up all the time because if they don’t have a
pull-up resistor then sometimes their output can just jump around randomly and
what we want to do is make sure that we have a nice consistent output from them
so we would use a pull-up resistor pull them up to 5 volts and then
whenever the usually south pole comes around to them then they’ll go down to
their 0 volt and it’ll give you an idea of where the position of the rotor is so
essentially they’re just feedback sensors but they are Hall effect and so
most people do call them Hall effect sensor boards on this particular motor
we have a little piece of rubber on the backside that comes out and that’s to
seal it up and to keep debris out a lot of times it’s not completely you know
100% watertight but it does the job then we have on the inside you can see we
have these solder tabs that come out of this particular motor and you may not be
able to really tell but the wires that are coming from the insider soldered
onto that board as well because we do have to transfer power somehow from the
inside to the outside and on this particular motor they use this little
solder board now on the inside we have the rotor and it’s pretty difficult to
push these out so a lot of times I’ll just push it through with a tool being
careful not to stab myself in the hand so here we go here’s the rotor and
here’s our can or our housing let’s look at the rotor first so on the rotor you
can probably tell that this has four segments to it and actually you can look
on it and see that they wrote 1 2 3 4 in almost legible handwriting the magnets
are affixed to the shaft but on a brushless motor we actually have a small
stack of laminations on the inside and that stack of laminations can determine
what size of magnets that we use and how they’re held together kind of a finer
points of the construction but it is important nonetheless so we have our
magnets right here and there are fixed to essentially a
small stator and then that small stator is affixed to the shaft of note is also
the balancing Cup on here and you can see a little bit of epoxy that they use
for balancing and another spacer or washer or shim as I would prefer to call
it on the front side and that one’s actually tight enough I’m gonna leave it
on there just so we don’t forget so that’s pretty much a rotor and this one
since that has four magnets it is a four pole motor but we also have examples of
two poles here and as you can see this is one solid magnet but it is also just
on the shaft and since it’s only one solid magnet we don’t always have a
stator or a set of laminations on the inside to fix it but in this case it’s
still a rotor it still has a magnet that’s affixed to a shaft so now let’s
look at the can so on this particular one we have the face bearing of course
and I should note that we also had a bearing that was hiding in the backside
of the end cap and the shaft goes through that that’s how you get the nice
smooth spinny action of a motor of course but on the inside of here and it
may be kind of hard to see we have the stator and all of the windings around
the stator as well so just like a brush motor we have copper windings wrapped
around the lobes of a stator and the patterns are different and we can do
Delta winding and winding there’s a lot of options on there and that’s more of a
finer point of construction that you really don’t need to know but there are
parts on the inside now I’ve talked about two pole and four pole motors and
there’s other ones there’s six pole there’s eight pole there’s fourteen pole
to give you an example of a fourteen pole motor this is a revolver this is a
revolver 540 and it takes apart actually pretty easy on this particular one no
circlip and here’s our stator you can actually see this data a lot easier on
it and you can see the copper coils that are wound around it and if you really
want to know it’s distributed lrk pattern if you really want to know and
this one is terminated with a why not that it really matters
it is and you can also see the bearings that the shaft rides to of course and
it’s a little easier to tell when we look at it this
technically it’s a rotor although the rotors on the outside of the motor this
time you can see that there’s a lot of magnets inside and this is a fourteen
pole motor and this stator has 12 slots so if we counted them up we would count
fourteen magnets which is seven pole pairs and we would count twelve slots on
that the same as any other motor as far as describing it but just a little bit
different construction when it boils down to it
and here’s another stator that we can look at this particular stator is 18
slots but you can see that there’s actually a difference between them we
have a much deeper slot depth on this one but a thinner section of iron around
the back and we would actually consider that the back iron of the motor in a
brushless motor it’s built into the stator wears on a brush motor the can is
actually the back iron of it but on this one you can see that there are
construction differences and the reason why I want to point that out is that you
can see you know the the interior diameter is different the cross-section
that we would put copper into is different on here and of course the
shape of the tooth is completely different as well and although these
would both be 18 slot motors you may think hey they’re going to probably
perform similar to each other they do not and that’s where kind of the black
magic of motors comes in that you can have two standards and maybe you would
think hey there’s a lot more room for copper in this stator over here it’s
probably going to perform better right well when it boils down to it it
actually doesn’t on this particular one the higher quality stator even though
the laminations are the same thickness and you know we could assume that all
the other components are the same when we build a motor from this particular
stator we end up getting almost three times lower no load losses in an amp
trawl so it’s if it’s a the one that I’m familiar with it’s about 1,800 kV and on
this stator that has kind of a blocky tooth we end up having about a 5 amp no
los which is actually a lot and then this one we have about 1.8 no load
losses on there in amperes and you know that’s just to say that the quality of a
motor depends on a lot of inputs that you have the quality of the steel
laminations the quality of the magnets themselves but also this the shape of
the stator has a lot to it and we’ve gone to pretty far links on our 2 pole
motors and our four pole motors and even our higher slot count motors like the
revolver to make sure that they have not only good Staters and good magnets but
the right shape for what we’re doing so the low-speed control of it the
efficiency of it it’s all really dictated by these I tend to like higher
pole count motors like the revolver being 14 poles it starts up really
smooth and has good torque but do you like it what about the noise and it
takes a long time to find the right Staters and of course you can engineer
one instead of using one off-the-shelf but it becomes extremely cost
prohibitive to do that sometimes and so a lot of times we just work with what’s
off-the-shelf and there’s a lot of different ones and and that’s good for
the market though of course you have your your lower price points and your
higher price points but a lot of times when you are paying for the higher price
points you’re paying for that engineering time and the time to make
sure that everything has worked into a good position with each other that it’s
all kind of a cohesive group that does exactly what you want it to instead of
just being hey this factory throws it off the shelf to us and we put it on
your shelf now if we look at some other designs of rotors sometimes they’re
small changes to them so the one in my right hand is a castle creations one of
their newer 14 series I believe this came out of a slate and then the one in
my left hand is one of our puller pros as you can see there’s a little little
thing on the end here and that’s actually a magnet pickup for the sensors
themselves and so instead of the sensor board
picking up directly off of the magnets themselves they have a secondary set of
magnets on there and that can actually help when you’re under really heavy load
to keep it commentating nice and cleanly so we are actually working on a design
for that on our own motors but just to be aware when you open up a motor you
may find something that looks a little different because not all motors are
design same but when it boils down to it they
all work on the same parts in the same functions so really that’s about it the
parts of a brushless motor are not that complicated there’s really not a lot to
them so what I’m going to do is just put it back together and since these are
really strong magnets it’s pretty difficult so I hope I can do this
without gouging my hand because I don’t have my my tools that I would normally
put it together with but essentially we want to put this in gently let it slide
through and then hopefully not not bang through take that shim off there we go
without damaging anything so we slip our rotor back inside the stator back inside
the can or the housing and we have to make sure that the shaft goes through
that face bearing all the way nice and gently just a little rocking back and
forth until it pokes through not quite there yet
sometimes it takes a minute there we go got it poke through I replaced my shim
onto the shaft and now our sensor board goes back on the sensor board and the
end cap now at this point it’d be a good time to point out this is our actual
sense report so this is where your wire is going to plug in so that it can tell
the ESC where the position of the motor is and of course as technology
progresses we have really less and less need for the feedback sensors the castle
creations newest es EES on the market since we’re doing this video now then we
might as well talk about what’s on the market now their sensor let’s start up
is actually so good that when you have a higher pole count motor you really don’t
need sensors and in fact with our revolver motor being a 14 pole it gives
enough feedback enough back EMF to the motor controller that we don’t even need
sensors on them and it starts up just as smooth as any other censored motor have
you ever had your motor breakdown on you while you’re on the trail and what did
you do to troubleshoot it but it’s always good to have sensors on the
or poll owners for sure to polls in particular for polls it’s always a good
idea but if you have a newer ESC like the Mamba X or the Sidewinder 4 then you
can actually get away with not using them sometimes so just keep that in mind
if you’re out on the trail and your sensor wire gets broken or if things are
acting up just try to unplug your sensor wire unplug the ESC plug it back in let
it reboot and run in a sensor list mode and you can kind of troubleshoot that
way if if that goes bad because really on a brushless motor that sensor board
is about the only thing that’ll go bad short of overheating it and whoops I’m
human I forgot to put this back in so I’ll just do that later off-camera but
there you go so I hope that helps you as far as the parts of a brushless motor
seeing me take it apart and put it back together you know you could probably do
that yourself at this point and understand what is going on inside them
and troubleshoot a little bit better so if you do have any questions post them
down below appreciate you tuning in today

32 Replies to “What’s In There! Understanding Brushless Motor Parts | Holmes Hobbies RC Basics Series”

  1. Another great video.
    JRH I'd really like to see you do a video on teardown and amp timing on a team puller 500 & 400 motor for lowest amp draw.
    If you already have a video on timing of 400 & 500 team puller motors can you post a link?
    I've learned a lot from your other brushed rebuilding and timing of 540 motors (crawlmasters).
    Thanks.

  2. Thank you John! I love my revolver, such a fine piece! The noise… takes me back to being in a dentist chair!! It took awhile to get used to it and it’s my favorite motor! No pain!!

  3. THANK YOU for explaining brushless motor details. I have a followup question though; recently I purchased a Reedy motor (Strongly recommended by my LHS) and on the back there is a series of numbers/increments and a rotatable pointer. I know it has something to do with timing but could you explain its purpose further in a future video?

  4. i rock my stubby revolver in my willys 1953 wagon. the sound is off the hook. it bothers others crawling with me at first, but it sounds like a turbo to most others.

  5. Thank you John!! I think it's really great, as busy as you are (you DO run a Company!!), you always take the time to do these Videos for US! Everyone should thank you….
    To this day, I have never had a Sensored Motor. 😱 Only reason, I'm that poor! 😢 I have only TWO Sensorless Brushless Motors, one being a HH Revolver. GAWD the Noise!! 😵 But, it's got smoother starts and stops than almost any Brushed Motor. (In my limited experience in Scalers)

    One Brushed Motor I think is SMOOTHER? Yours!! 👍👍 It's an older 30 Turn Handwound. It's been through about 10 sets of Brushes, I've polished the Comm several times, and Turned it once – I over 4 Years!!! It's literally the most satisfied I've ever been with a RC Motor! Seriously.
    I hope Holmes Hobbies doesn't phase out Brushed Motors.

    Now, I live in Southern Arizona, and my Rigs have NEVER gotten Wet! That may have improved my results.
    With the little money I have to spend in this Hobby, as much as possible, I will always purchase Holmes Hobbies Products!! I fought for this Country, I'm damn sure going to support it whenever I can. Your Company is a fine example of American Pride, Craftsmanship, Quality, and good Old Fashioned great Customer Service!!! 👏👏👏🏆
    ……. Maybe someday I'll be able to try a good Sensored Brushless System. I hope so.
    Merry Christmas to you and your Family!
    Carmine 💥 ⛽

  6. Man I picked up a few low voltage 120 size brushed motor from my work. Found several in other things that were made in Germany. The other Taiwan. The German ones were so much smoother and efficient its ridiculous

  7. You know I love my Revolvers! Many complain about the noise…for me it's a grand opportunity to educate those interested on exactly what it is they are hearing and why I'm such a fan.

  8. Thanks John I really enjoy being educated and your products because of your business and production my hobby went from fun to bad ass thanks John happy holidays….✌

  9. As usual I'm impressed, & we get what we pay for thanks, personally never got into the nuts & bolts of how things actually work, got into the hobby in '08, ish, first model was a Axial AX10 Scorpion, so that's where my head is & thanks again

  10. Could you go into a little more detail on how the number of poles factors in. With regards to how we use these in our hobby. Would having more poles always be better? Or are there situations where less poles are more important? And do the benefits related to the number of poles apply for brushed as well as brushless?

  11. Nice vids John Holmes:) I got a quick question hope you can help me..I'm planning to get axial honcho 2..I know its brushed motor on it I would like to ask if I can change it to BL motor in the future ( less maintenance ) that still run or crawl on rock,dirt for a guy loves trailing? Btw I'm newbie and the brand's available only in my country most are China brands. Maybe there's similar specification that match to a branded ones. Appreciate your help…

  12. I live the sound of the revolver. Cant wait to get one. Just upgraded to brushless. And went with mamba x with castle. But definetly want one of yours.

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