Welcome back to Teaching the Unteachables, where we dive into teaching and learning
methodologies for professionals like you. This episode brought to you by Regal
Rexnord Gentec Motors, the leading brand in electronically commutated motor
technology. Learn more at regalrexnord.com.
Well hello friends, thank you for joining us once again. So we have a very special
series to bring you, brought to you by our good friends at Regal Rexnord. Chris
Mahali, how are you sir? Very good, thank you. So we're going to spend four sessions
together. So we're gonna do four different months the first Thursday, the
first show of the month, and we're gonna dive deeper into ECM motors. So this week
we're gonna talk about ECM constant airflow motors. The following month we're
gonna dive a little deeper into ECM constant torque. Then we're gonna go into
ECM condenser motors, and then we're gonna talk about the effects of airflow on all
of the different ECM motors. And you go, well why are we diving into ECM motors?
Well for me personally, it's a great topic to talk about. So when we start
understanding motors in general, and the differences between like permanent
split capacitor motors and DC motors, and ECMs in particularly, it gives us a
better understanding of technology, right? We're spending a lot of time talking
about inverter technology and transitions into new generations of heat pumps. And
if you have a confident understanding of ECM motors, you'll actually have a more
confident understanding of inverter compressors. So Chris, thank you so much
for joining us today, and let's dive a little deeper into ECM motors. All right,
well let's dive into, I consider you one of the motor masters of our industry, one
of the lead technicians and trainers. And I always like to president that, that a
lot of people don't understand that you can be a technician and not be a good
trainer. You could be a trainer and may have never actually been a technician,
but when you have the combination of the two of those, that's when the magic
happens. That's why I enjoy hearing you so much. You can speak the truth about
what we see out in the field. So, yeah, so all right, let's see a little bit more
about constant airflow motors. All right, just an overview of, you know, when we say
constant airflow motors, the industry knows these motors by the term variable
speed. Yes. And I don't like the term variable speed, but that's, you know, once
you get to know me, you know, I have pet peeves just like everybody else, and
variable speed is one of them, because if you take a single speed motor and you
change its load point, its speed changes. So every motor is variable speed if you
go by that definition. Oh, so the reason I like the term that our engineers
gave this motor way back when constant airflow is, if you really just focus on
the words, it's a constant airflow motor, it's kind of like if you focus on the
words cruise control on your car. When I set the cruise control, it maintains
70 miles an hour. When I have a constant airflow motor, I might be maintaining
airflow, and that's exactly what the motor does. So you get a, you kind of get
a better understanding of what the motor does when you think of the, when you, when you
listen to the words constant airflow, constant torque, constant speed. And so
we'll start off with the constant airflow motor in this session, as you said. I do
like to, for just for people that are maybe not as familiar with these motors,
to know why. Being that it is our premium level product, it's typically found in
your premium level HVAC equipment. So your, your two-stage, which, you know,
entered the industry back in the late 80s, same time ECMs entered the industry.
Right. Wait, wait, what? 1980s? Yeah, late, late, late 80s. I may or may not have had a mullet back then.
Oh yeah. I wish I still had some of that hair. So yeah, late 80s with the two-stage,
and then that obviously progressed into three-stage, and now we have modulating,
you know, systems. That's where you're going to find the constant airflow variable
speed motors. Not so much in your single-stage equipment, and not so much in your, not, not
really at all in your, you know, builders grade level, low level equipment. So what, if you don't
sell premium level systems, or you don't work on premium level systems, or a lot of them, you may
not be as familiar with these motors as others. So I'd like to cover that early on. These motors
are also what I like to call communicating, and I like that word because it immediately
says something different than multi-tap. Absolutely it does. You're not going to be moving
wires from one tap to another to change the speed of the motor. You're going to be doing
something else because the motor is actually communicated with information from the OEM
control board to the motor, which dictates how the motor performs. So to change the performance of
the motor, you're going to be adjusting dip switches, or jumper pins, or you know, lately
many manufacturers are moving to the fully communicated system where the thermostat's
communicated and all the menu selections and even fault codes are at the thermostat. Absolutely.
And we've talked about that quite a bit on the communicating systems that we're typically using
a variable five volt DC signal. So it's not like a light switch of 24 volt AC. You know,
like if you think about it like a standard thermostat or a PSC motor or a single or two
stage compressor, we're talking about a switch that applies voltage so that we have a load on
something. When we talk about communicating, now we're talking about variable signals,
just like we're talking about an internet connection, any type of a serial signal where
we use variable inputs and outputs, like all of our inverters are using pressure transducers and
temperature thermistors, typically all from a five volt DC signal, a lot of our communicating
thermostats. And on that five volt DC signal, we teach, well, we're not here to learn how to read
the command that's going through it. We're learning to read that there is a command,
that there is something happening there. And so that same principle applies when we get into ECM
motors. And when we understand that you can look at a motor now and be able to go, hopefully by the
end of this class, you're going to look at that motor and you go, ah, that makes so much sense now.
And yeah, this is a fun topic. Yeah, that's my hope. And actually I'll, you know,
I'll kind of give away the presence early. You know, in my opinion, these motors are actually
easier to work on induction motors, because there's really only a couple of inputs and
outputs to check. And when we get to the point of understanding that an ECM is a motor that's
operated by a control and that control is a circuit board microprocessor or whatever.
And I'm sure you've taught this or had somebody on your show that's taught this, you know, any control
diagnostics is just what's the input, what's the output. And once you, once you understand that,
it becomes real easy. So the last bullet point I did want to mention before we move on is the
constant airflow programming. Each of these motors actually has a constant airflow algorithm
because that algorithm has to understand, uh, airflow in CFM has to understand static pressure
and it has to correlate that to torque and speed in the motor. And we're not going to take a,
we're not going to dive that deep into the motor in this particular show. I mean, we could,
but that would be a whole. No, that was 100 feet would be good. Cause that a way every technician,
every instructor knows, okay, I didn't know much before. So we started here and I got to
here where I understand exactly. I'm not going to be an engineer. I don't need to know the hundred
foot down into the algorithms, but if we wanted to go deeper, let me know in an email, let us know
in the chat, maybe some other episode we'll dive deeper into algorithms and what those inputs look
like to dictate the output. But for the most part, we're talking about troubleshooting and
understanding how these things operate and that we're definitely going to be able to do today.
Yeah. And the main reason I like to bring that bullet point up is so I get asked quite often,
can I take a ECM from a carrier and it's, it looks the same, has the same plugs and put it in a
train. Right. And I've even had people tell me, well, I've done that and it works. So what do you
think about that? Cause cause they'll hear me say, no, you can't, you may be running, but it,
is it running at the right airflow? Because that is demanding or right. Cause that, that might be
like taking the computer chip out of a Chevy and putting it at a Ford. Well, if there were both V8s,
it may, it might fire the system, you know, the motor up, but is it running at the right horsepower
and running at the right oxygen levels and blah, blah, blah. So, so you need to understand that
these motors are actually engineered, not just by us, but also by the end user, which, you know,
my end user is the HVAC manufacturer engineered by them to match the performance of each system that
they go into. And some of those manufacturers have algorithms that work opposing from each other.
So even if something happened to run, when you get a call for G as the, it, the speed is demanded to
increase, the algorithms could actually be calculating the opposite direction and slowing
a motor down. That's a whole nother story. So it's crucial that we're matching the correct
program. And it actually comes down to even model of the furnace because the same model series of
furnace, I need different air flows for a 60,000 up flow and down flow, 80,000. So it's very specific
for the actual controlling to get that airflow. You bet. And you just covered one of my slides
coming up. So they're good. So just to take a little step deeper into what is communicated means
our motors. And so the first motor we ever built, and when I say we, the ECM technology was introduced
by General Electric back in the late eighties, we acquired the 48 frame motor business from General
Electric, including induction and ECM in 2004 ish rebranded it under GenTech. So that's why I keep
saying we, even though it wasn't we, you know, kind of the, what does that say? It's saying the Royal
We's. I don't even know what that saying means. But if you go back to even the early nineties,
all of our constant airflow variable speed motors have two plugs. They've got a line voltage plug
and they've got a communication plug. And actually from the early nineties all the way to today,
there's really only two different motors. There's motors with a five pin line voltage plug
and a 16 pin communication plug. And then you've got motors with a five pin line voltage plug
and a four pin communication plug. And here's, I'll warn you, here's one of my really bad jokes.
You know, what's the difference between the 16 pin motor and the four pin motor?
12 pins. I told you it was going to be bad. I told you.
But the difference in all sincerity is the type of communication. Right. So, and I,
anyone that's been to my class has heard me refer to these motors like printers. I use printer
analogy, computer printer, motor, OEM board. Right. So if anyone that's listening had a
printer 15 years ago, right. You remember that the cable between the computer and the printer was a
very wide cable called the parallel port, I believe. A lot of pins in there, easy to bend them,
not get them in the right place. Right. That was the technology of the time, early nineties,
when those 16 pin motors were designed. Absolutely. And I get asked often, well,
why do you still make them then? I mean, the printers don't use that technology anymore.
Well, we keep making the motor because the manufacturers, they keep asking for it. Right.
Absolutely. But we did introduce the four pin motor, which is akin to a USB port. If you ever
look at a, and I think I might have one here, if you ever look at one of your USB plugins,
I know you can't see that, but if you look at your USB plugin inside, there are four pins.
And those four pins are communicate, transmit, power and common. So when you want to communicate
with something, you really only need two wires. So for the OEM board to talk to the motor,
I only need two wires to come in and send information to the motor. But if I want the
motor to provide communication back, you know, I'm running, I'm here, I'm running, then I need a
transmit channel back. So that's how the current four pin motor works. So when you look at the
four pin motor, you know, again, trying to make things simpler in your mind, not those big scary
ECMs, just think about a motor with a five pin plug and a USB port. Cause that's really all that
four pin plug is. Yeah, absolutely. Well, and like when we talk about things like pressure transducers
on a inverter system, or even your pressure transducer that is on your digital manifold
gauges, you know, we've got a hot, we got a common, and then we have a variable coming back. So when
we start getting into serial communications, that's typically what we're talking about is
we're talking about supplying a constant and returning some kind of a variable so that we
can talk both ways. Sometimes we have the extra where we can variable forward and variable backward.
We're just talking back and forth on a simple wired connection. Yes, sir. And a little later,
we'll talk about what some of those voltages are, because obviously you're not going to have an
oscilloscope or a device that can actually read that binary code, but you can measure most of
that communication with either AC or DC voltage settings on your meter. Nice. All right. Yeah.
So, so what does the communication do? The communication is the on off command for the
motor. The line voltage to an ECM is connected continuously. Yeah. And we do that on purpose.
And I, I didn't take my motor apart, but I'll, I'll do it while I'm talking. Do you have one
taken apart? Yeah, absolutely. Let's say Daniel will throw that camera. You got the control off
already? Yeah. No, but I'll do that. No, no, you got one right there, right there next to you.
You got a control. Yeah. So if you look at that control that's next to you there, um, inside,
you're going to see, um, some little capacitors. Look at those cute little guys. Aren't they
adorable? Uh, those capacitors are about a thousand microfarads a piece. Um, so they,
they carry a punch. So the reason I bring this up is I get asked all the time, why is the motor
continuously powered? Why not switch the line voltage on and off instead of switching the
communication? Sure. And it's because of those capacitors. Every time the line voltage is turned
off, the caps discharge, discharge it, take every time you turn the motor back on, they have to
fully charge and they draw a significant inrush of power, uh, to do that. So we leave, and that
would cause the manufacturer's circuit board to have a more robust relay. If we were to be turning
that line voltage on and off, controlling that load, I didn't rush load. Yeah. Exactly. So we
leave the motor powered all the time and, and again, uh, relating it to something like the printer
or even your home stereo or, I mean, do you unplug your microwave when you're done working it?
No, it's energized all the time. You press the on off button and that sends the command to the devices to
turn on and off. So that's why we, uh, that's why we do it that way. And the communication controls
that. Um, but it also controls the, the communication also controls the airflow.
The motor is going to operate it. So if the dip switches, uh, you can see the square around the
circuit board on the screen, if the dip switches are not set correctly, even the motor turns out,
even though the motor might turn on, it might not be producing the right airflow. And the only way
to adjust that is to change the communication coming to the motor. Right. Because, uh, and I get,
I have been asked, well, so what if I take the wires out of the 16 pin and move them around?
Um, well, usually that's going to cause the motor to not run because you've rearranged the
communication and it's not going to like that. Um, so it's, it's not a tapped motor. You're not
going to change speeds by adjusting the wires. Exactly. You're going to adjust the dip switches
on that board on the screen, which is going to change the communication coming to the motor.
Sure. It's going to change the voltage or the pulse width modulation of that voltage so that
it gets an idea what the command is or the serial communication. If we're talking about the four pin
motor. Exactly. Yep. The last bullet point I did want to touch and where I think we're going to
get it on the next page as well, but you are going to need the OEM manuals to adjust airflow.
Unlike popular belief, uh, the, you know, HVAC systems don't come from the manufacturer perfectly
set up for everyone. They're going to go into. Yeah, I know it's a surprise. They're, they're
a drop and go package, aren't they? Plug and play, right? You just plug them in and they play.
These things are so smart. I don't have to do anything. I just, these new variable technologies
and communicating thermostats, I just hook them up and go. You know, they are getting smarter,
especially the ones with communicating thermostats. They, the thermostat can talk to the outdoor unit
and actually set that airflow. Yeah. Uh, but you, you will need the manual for some of the settings.
I carried books and reference and books to have the manuals today. You know, you're going to get
them all on your phone. You're going to Google a model number and probably find it, but, um,
become that technician. Sorry to take a segue here. No, no, absolutely. Um, please become that
technician that on every job pulls up the manual and checks to see if the system has ever been set
up properly, uh, and measures the airflow. You will just be amazed at how much better systems will run,
how many fewer repairs you have customers that'll tell you, I never knew the air coming out of that
furnace could be warm. I thought it was always out, you know, it's, it's a high efficiency. They
told me it would be cold with one dip switch setting all of a sudden, Hey, yeah, that feels good. So
there, there's my, there's my punch for the industry. No, absolutely. I seen it so much when
I was doing technical support calls that, you know, I would do site visits. You know, first the call
is all right, let's verify that we got proper airflow. Oh yeah. Yeah. I got proper airflow.
And the most common call that I had on my constant airflow motors is that they were tripping out on
blower fault codes. And the beauty of the communicating system is that it can send a signal back to
the control board when it senses high temperatures and where do those high temperatures come from?
Well, they come from excessive load on the motor and it is almost every time I would find excessive
static pressures. And we'll dive into that later on, probably episode four, when we get into
how airflow affects them. But we always have to remember that a motor is a motor and excessive
pressures are always going to have negative consequences. So they can fix themselves a
little bit. They can tweak, but they definitely can't fix bad habits. Yep. And we will touch on
that just a little bit here for those of you that are going, ah, I was really hoping they'd talk
about that today. We will talk about it a little bit. Oh, you got to come back for more. That's
all your friends too. We'll tease them. Yeah. That's right. So, uh, you know, a big part of the
setup is simply the cooling and heating airflow. Those have to be set correctly. Beyond that,
everything else is creature comfort. But these systems truly do have some pretty amazing creature
comfort abilities now and not just comfort, but even, you know, if you, I live in Wisconsin,
right? High humidity for us is when the windshields are wet in the morning and we freak out because
the dew points are high. And, you know, for those of you in Louisiana or other humid markets, you
just laugh at us because, you know, that's your wintertime conditions, right? My peak summer.
But, you know, there are truly some amazing features on these new systems that can adjust the,
um, not only the amount of air, but the, um, the, the, uh, time that the airflow runs at certain
levels to get more latent versus sensible removal out of the coil, uh, during a typical cooling call.
So besides the fact you can have first stage, second stage, you can also then have a first stage
and second stage that are running at part airflow for a certain amount of time and get more latent
removal. And then, you know, of course, because the manufacturer has engineered all this in,
you can get all that without having to worry about freezing the coil by just, you know, dropping a
speed. And so those are all the other functions there. Um, some of, some of them are simple
selections where you say, Hey, I want more dehumidification, or some of them are, uh, more
sophisticated where you can pick a profile that matches your market. And some of them are even,
um, more sophisticated where the unit will look at the humidist that or humidity sensor in the
thermostat on the wall. And it will gauge whether it needs to go into dehum mode by what's actually
happening to the conditions in the home. That's a whole nother topic. That could be a fifth
conversation right there. Cause I can preach all day long on proper airflow for dehumidification,
especially when it comes to inverter operations. So we need to bring in Rick Kinsel for that one.
So he's the expert on that. But yeah, but, you know, so the thing to keep in mind is it's not,
the cooling and heating airflow are not always going to be properly set up for every job the
unit goes into, but all of those other settings, the creature comforts and the dehumidification,
they're going to be set at a default setting for, you know, for general USA, not for, you know,
Fargo, North Dakota compared to Miami, Miami, Florida, which is, which are going to be drastically
different climates. So you'd have to go in and, and adjust those. And my, you know, my, my, my,
my plug as a former technician, maintenance technician, service technician is, you know,
this customer paid for a premium level system. They're not getting a premium level system.
If we don't set it up properly, any, and each job is different. I mean, even here in Wisconsin,
I would set up systems for maximum dehumidification. Why in Wisconsin? Well,
I've got a family that never opens the windows. You know, they're asthmatic, whatever the windows
are always going to be closed. What they're looking for multiple people living in the house. Maybe
they're, and, and I hope I don't get in trouble for this. Maybe they're Italian and they cook a
lot. Right. No, it makes sense. So, you know, there's going to be a lot of moisture in the house
and a lot of showers in that house. And I want to get that humidity out of the house. So there,
there are reasons to set those settings, not only based on re region, but also by the design
preferences. Yeah. All right, everyone. Well, thank you so much for joining episode one of a
four-part series next month. We're going to be diving into constant torque motors. You're going
to go, wait a minute, didn't we just talk about ECM? So we'll go, no, we're going to talk about
their cousins, the constant torque versions of those. Yes, we are. All right. Well, thank you
so much, Mr. Mahali. And we look forward to seeing all of you again next week on, did you know the
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