Welcome back to Teaching the Unteachables where we dive into teaching and learning
methodologies for professionals like you. This episode is part of episode 74 of
Did You Know? The ESCO HVAC Show. Learn more about Regal-Rexnord at
regalrexnord.com.
Alright so this is where we left off in the history lesson. We took a
side off ramp to PSC motors for a little bit but we left off 1986 saying
that back then all indoor blower motors were using PSC technology. So if we fast
forward to 2005 and it'll become clear in a few minutes like why did he that's
a very obscure year to jump to but it'll make sense there's always a method to
the magnet. I need to borrow your Einstein here when I say that. So ECMs
were introduced in 1987 that's why I chose 1986 as the starting point because
the very next year we started ECM we started introducing ECM technology. So if
you fast forward to 2005 which if my math is correct is about 18 years later
we see that in the indoor blower motor market of brand new equipment that ECMs
had gained about 15% of the market share and I don't know about any one of you
that may or may not you know do investments or focus on investments or
investment in manufacturing companies but that's not a good business model to
penetrate only 15% of the industry in 18 years. But there's a very good
reason why and I'm gonna explain that in just a minute. So 18 years later
2005 we've got ECMs in the industry we've gone through multiple iterations in
that time frame. Anybody's been around long enough remembers the old
square back one and then we progressed to the one with no paint on it
that looked kind of weird and then the 2.3 which is the name of this motor
that went from 98 all the way to 2013. So whether it's air handler package or
fossil fuel again only about 15% of units were using ECM. So before I tell
you why only 15% of the industry had had switched to that technology let's take a
little another detour and talk about what is ECM because we've we've done
three discussions so far each one of the ECM technologies and we've drilled down
explained the nuts and bolts of how they work the diagnostics the airflow but
we've really never explained the technology itself the what's going on
on the inside. So ECM of course stands for electronically commutated motor if
you're one of those typo experts you know you don't like to type ECM or
electronically commutated motor motor so you know it's really EC motor.
Yeah, well and I have to say that because very recently there was an
I think was a manufacturer may have may have been another training
organization but they were calling all their motors EC motors and I started
getting these phone calls I say hey are these EC motors brand new are they just
like yours like it's an ECM you know you're on the phone you could just hear
them turning red like I should have known that.
I'm all good never mind but we have these other terms that also get used and
brushless DC and permanent magnet and the thing is is these terms are a part
of the technology of the motor so an ECM technically you know I'm gonna read this
verbatim it's a brushless DC three-phase motor with a permanent magnet rotor the
motor phases are sequentially energized by the electronic control powered from a
single-phase power supply probably could have read it without staring at the
screen but I like to get that one exactly right because it was written by
one of my engineers and there you go I want to plagiarize properly so but we
end up with these terms what is permanent magnet motor PMM what is BPM
brushless permanent magnet BLDC what these all mean well basically to
understand that you have to understand everything that's going on inside of an
ECM because these terms are bits and pieces of the technology so in an ECM
motor in the control so you see here I've taken the control off of the motor
so here here's the motor I know you can still see me on the little screen there
yeah and here's the control I know you can see it on the screen but I wanted to
pop it up so the okay so I'm at the point where I've got AC power coming in
I'm converting that AC power to DC power and now I have a clean DC power source
inside my ECM control okay good to go yep that that volts DC power is gonna
power my microprocessor just like it does in your home computer your laptop
your phone you know any anything you're using but that DC power is also going to
go through my frequency drive and it's gonna operate the motor so going to the
motor and this is where this is where in many classes I'll finish this sentence
or this phrase and I'll pause and I can see a little bit of smoke coming out of
here yeah yeah this right so so what is actually going to the motor is it is it
DC power or is it AC power well it on an oscilloscope but actually it would look
like an AC sine wave it looked like a three-phase AC sine wave but if you look
a little closer you're gonna see ripples in in the in the flat areas of that sine
wave and what those ripples are is that is not actually a clean sine wave it is
a PWM frequency drive that's turning the power on and off on and off so it turns
an on and off from zero to positive voltage on and off from zero to negative
voltage over over a proper amount of timing and it ends up looking like an
AC sine wave and you might think well boy that would have to be going on and
off really fast and it is it's around 20 kilohertz which is 20,000 times per
second right so I you know my analogy because I like analogies they help
people remember things and relate so the lights in most of your rooms are
probably you know fluorescent lights and they're running off a ballast there
they're actually turning on and off because they're running at a certain
frequency but you know my light doesn't that I don't this isn't you know this
isn't the 70s this isn't a strobe light you know I'm not I'm not doing the but
but but yet this light is actually turning on and off so quickly you can
just looks like continuous light and so that's what's happening in an ACM motor
I am truly sending DC power to that motor winding but that DC power is being
pulsed on and off at proper intervals so fast it just looks like a three-phase
sine wave going to the motor and I put these two up here and I didn't want to
get too nerdy in here and I didn't want it I didn't want us to be here till like
10 o'clock at night but yeah well we've already gone down the rabbit hole now
we're going now we're going into the rabbit hole cave so if you look at this
sine wave in the early years of ECM technology this was called sort of a
trap drive a trap wave trapezoidal looking waveform and so technicians
would often ask in the early years you know why does the motor kind of rock
rock rock and then and then take off and so again if you think about this
technology came out in Windows are sorry in 87 you know do you remember how
powerful Windows 95 was and how it was right so so think about that era
processor being in this motor and having the responsibility for directing the
frequency drive to do all this work so it didn't do it very fast it had to get
rotor positioning back from the motor to know that it was starting the motor in
the right direction and so all this took a couple of seconds to happen so in the
early ECM technology the motor would and then and then take off yeah but if you've
ever paid attention to an ECM from the last 10 years or even five years they
just seem to take off there's really no rock if they do rock it's so slight you
have you got to you got to be like I'm gonna catch it I'm gonna catch it you
know and it barely moves well that's because now we have what's called the
sine wave drive and the sine wave drive creates a sine wave that actually looks
almost exactly like a true waveform still being pulsed but now that I've got
a more powerful microprocessor I can I can create that wave I can stitch that
wave together more cleanly and I get less of that starting fluctuation man now
we're getting into the nuts and bolts this is what we teach in class right
that's the whole point of diving into what are we looking at how do we teach
this in our class how do we make this more comfortable and so it's important
to understand what that control is doing what our motor is doing how it's
constructed I think this is a good time I want to introduce a another perspective
for us to have in the classroom when we're talking about ECM motors like so
if we take the the mod the control off from that motor Chris we're stuck with a
three-phase motor that has a rotor inside and we have our stator on the
outside in a three-phase position now I want you to think about this for a minute
because I get this question fairly often are there are there ways that we can show
the motor in in an electrical way that makes sense for technicians can we use
it for different purposes I do this in classroom and I've resurrected one of my
old training projects to be able to show that that three-phase motor is really an
interesting component that we can use for other purposes now we've talked a
lot about the construction of it and I want people to pay attention see if you
catch the terminology that could be could be construed a little bit off but
it's kind of right I want you to think about it yeah I need to do a little
adapting to it but I do this together just for our educators to be able to
put motors into a perspective that is a little bit more hands-on so are we ready
all that beautiful green footage here we go so when we talked about the
induction side of a motor Chris what we were truly talking about was a slightly
different style of motor so I really need to reframe that a little bit and
talk about the motor so let's go let's look at what induction really would look
like so I took this motor apart and this is obviously an ECM but if this were a
PSC motor the the rotor would would be made of aluminum bars and I would still
basically have the same stator I'd still basically have steel with copper
wrapped around the the laminations and so in a PSC motor this this rotor would
have no magnetic effect when there's no power to it but when I put energy to the
stator and I start creating a magnetic field around this stator that magnetic
field is going to induce a magnetic effect into the rotor and that's
actually where the term induction motors comes from that rotor doesn't have any
magnetic effect and can't follow the rotating magnetic fields until the
rotating magnetic fields establish themselves and do some of that magnetic
effect into the motor it's also why the PSC motor is less efficient than the ECM
it doesn't have near as much to do with the electronic control the electrical
efficiency doesn't have near as much to do with the electronic control module as
it has to do with the permanent magnet rotor on the in inside the ECM so when
you add a permanent magnet rotor to the so this is a three-phase motor no no no
qualms about that question is and this is maybe a this is a question of maybe
you know engineers and technicians deeper than me is it an induction ECM
motor than an AC ECM motor is it easy our well three-phase motor is it a you
know induction AC or DC three-phase motor well I've got a permanent magnet
rotor in the middle okay so I don't need to induce a magnetic effect from the
stator into the rotor to generate that magnetic magnetic effect it's already
there so it really is somewhat improper to call it an induction motor but if
you're teaching this to a technician who's not an engineer and just needs the
concept of oh that's just a basic three-phase motor then calling it a
three-phase induction motor helps them understand oh it's something it's gonna
have three windings those three windings if they're working properly should all
them out with the same ohms I reverse any two phases the motor will change
direction so I think it's okay at a high level well when I'm teaching
contractors and technicians yeah it's a three-phase it's a three-phase AC
induction motor because they're gonna get that impression of how they would
diagnose it and that's perfectly fine at the technical level it's really just a
three-phase DC motor or to what was used earlier three-phase brushless DC motor
so and when I bring that up I'm sorry the kid in me always wants to go back to
my Tyco race car sets right little Tyco cars those little those little
rotors were little magnets and you know if you when you when the car was
completely destroyed you'd tear it apart and you'd throw the magnet at things see
what it would stick to absolutely and then when the car would slow down you'd
go to this you'd go to the hobby store and you buy new brushes and what did the
brushes do the brushes flipped the polarity so that the magnetic field kept
going back and forth and made the rotor go around so that's where these terms
come from brushless DC is it a DC motor well technically yes because the power
being sent to the motor is DC it it's not a C but it looks like a C to the
motor and we generate the same alternating current in the winding that
causes the rotor to follow we just don't need to induce that current into the
rotor to create the magnetic effect so a couple of things happen from that
permanent magnet rotor we get not only better efficiency but we also get a
smaller stators and you look at the size this I probably should have a measuring
stick out but from here to here from from a vent to vent that's about an inch
and a half that is the stator stack of a half horsepower ECM motor if that was a
PSC motor that stator stack would be easily an inch longer so how is an ECM
stator that's shorter less copper able to still create a half horsepower of
torque it's because in a PSC motor I'm wasting a certain amount of energy
magnetizing that rotor so I need that bigger stator to create the same my
torque with the permanent magnet rotor I've already got all that energy that I
would have had to induce I've already got all that energy in the magnet I don't
have to use that energy in the mat to create the magnetic effect therefore my
stator becomes even more powerful in a smaller size so a couple of things
happen from the permanent magnet we get the better we get better efficiency and
we also get a smaller profile of the stator stack of the motor one more point
of discussion before we leave this this particular rabbit hole I think I feel
like there's more to come on the on the left you see what the early rotors looked
like in ECM motors and they were using what was called iron ferrite so it's
roughly a quarter inch thick I believe this one is an iron ferrite yep I'll
hold that one up to the camera if you want to see it so it's about a quarter
of an inch thick and you can see it's it's actually in this one's actually in
three segments you can kind of see it there this the segment goes from from
here to here and then the next segment goes to here you can kind of see that
little dimple there and then comes around to here so so three individual
pieces of iron ferrite but as technology progressed we started using neodymium
and neodymium I'm gonna throw a number out it's probably not right but I'm gonna
use it you know it's 10% 20% 30% stronger than iron ferrite so what happens is I
end up with a much smaller magnet which means my my my rotor profile changes
because that neodymium is actually stronger than iron ferrite you may you
may have noticed in the last five to ten years ECM motors the stator stack has
have even gotten smaller and the reason they've gotten smaller is again because
the rotor has the rotor field has has been made stronger with the neodymium
magnets so that's just a little bit more information about the rotor that won't
help you diagnose the motor or set your airflow or sense but it's it's a lot of
fun when you know how the toaster works without having to take the whole thing
apart so we're gonna apply that to the constant airflow motor that was the
technology that was introduced back in 1987 constant airflow we we left off at
2005 about 15% of the industry had started using constant airflow motors but
over 18 years well it's a long time you'd think that it would have had more
of an impact on the industry but it makes a lot of sense when you understand
that constant airflow motors are only used in premium tier systems so you know
two-stage heat two-stage cool systems started in the late 80s same time these
motors were introduced and so this motor the constant airflow premium level motor
was only used in premium level systems so if you think about that pie chart
again 85% still PSC 15% premium level ECM that kind of agrees with the way most
contractors sell equipment right about 15% depending on the market your region
you're in 15% is your premium level systems and the other 85% is probably a
mix of your mid-tier and your builders grade level equipment and when I'm in
front of most contractors again it's pretty much you know how other than the
the rare contractor that sells a lot of premium or no premium that's it pretty
much washes out with the industry so it makes sense why that motor you know it's
kind of like we kind of launched I like to use again I like to use goofy
analogies count we kind of launched like Tesla right we came out with our
$80,000 car first and then later came out with the affordable $35,000 option B
option B for the masses right exactly then and I don't think I've mentioned
this yet so ECM motors as a whole and they can be a little higher a little
lower as a whole and ECM motors around indoor blower motor outdoor fan motor
48 frame one horsepower below I don't want anybody like yeah I know my motors
89 so they're roughly 80% efficient they can be as much as 85 and they may be
they may fall a little bit below 80% depending on where they're operating but
they're about 80% efficient if you remember I said that PSC motors are
between 60 and 70 depending on where they're operating if they're operating
at lower speeds they could be operating as low as 50 or 40 percent efficient so
we're anywhere from 10 to 50 percent more efficient than the PSC motor
depending on where we're operating it and again keep in mind this motor was
primarily applied to premium level two-stage systems so it's going to
spend a lot of time operating at the lower speeds because two-stage systems
spend a lot of time operating in their first stage capacity yep and then you
know we talked about this in in episode one you know these are communicative
motors if you want to know more about that go back to episode one and then you
can get all that information we're we're in high-level mode here so we're not
we're not drilling we're not drilling down there these motors again often
referred to as variable speed and they have they're made in two very common
styles and I say to we make them we gen tech the formally branded GE motors
make them in two styles one with a five pin line voltage and the 16 pin
communication and one with the five pin line voltage and the four pin
communication one of our one of our largest competitors makes the motor
similar to the five pin four pin and then some of our other competitors make
either different size pins or they use just all wires but almost all of them
are using either PWM or serial communication so and the only reason I
say that as you go back and watch episode one you're not really you're not
going to just learn about gen tech motors you're going to learn technology
that will apply to multiple brands of motor technologies indeed so here's
where it gets really interesting besides the electrical efficiency and this and
this weird thing called the permanent magnet rotor these motors by by program
can have an operating range of 300 to 1500 rpm that's pretty crazy so that's
like going from an eight-pole motor or even a I don't if there is such a thing
as a 1012 yeah there's 12 pole motor all the way up to a six pole motor all in
one motor and the manufacturer of the appliance doesn't have to buy ten
different motors they can program that motor as it's coming down the line you
know in this system I need between 600 and 800 rpms for my two-stage system and
the next system I need between 800 and a thousand in my next right they can they
can program that motor for multiple systems without having to buy individual
skew ratings for each each you know wired and wound motor highly sought after
for those premium level system very versatile for the manufacturer also
opened up the manufacturer to create airflow points that they're just were
not possible with psc motors I don't know if we talked about it in any of our
episodes but you know the Merv rating has has come up after cove it Merv 13
running your fan continuously and running your fan continuously is very
valuable for many reasons but if you've got a psc motor it's gonna cost you
quite a bit of money in an ECM I'm I'm actually running 50% or more efficient
than a psc motor when I'm running at 600 or less rpms and any and this ECM for
example is gonna run 600 or less rpms still around 80% efficient Wow so that's
that's pretty huge when it came to IAQ yeah indeed
we have some fun all right everyone I know it's been a long evening I'm so
grateful that you hung out with us all of these presentations are available
for you on YouTube you can go into our e-learning network at the HVACR
learning network and you can actually get credit for these courses if you're
looking for that for continuing education so check that out we'll see you
all at the conference everyone have a wonderful evening and we will see you
next week on did you know the Esco HVAC show what a great time