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 everyone, thank you so much for joining us once again on Did You Know?
The ESCO HVAC Show.
Now we have done three different episodes, Chris, on talking about ECM motors.
Isn't that crazy?
Can't believe it.
I know, we're four months in right now.
So we've covered ECM constant torque, we've covered ECM constant airflow, we've covered
ECM condenser motors.
And so what we're going to wrap up today is kind of going to like a high level view, demystifying
ECM motors in general and bringing in the ECMs really into the classroom.
I'll also put together a fun little video we're going to share that I want to get your
input on and find some potentially incorrect words.
So I want you to pay real close attention to it.
They're close, but there's better ways to explain it.
I'm afraid.
Oh boy, we're doing a lot of fun.
I'm rolling up the sleeves.
Let's go.
Here we go.
And everyone, as always, we truly enjoy you hanging out with us, spending your time talking
about a changing industry.
What do you think, Chris?
Want to bring some clear definition to what ECMs really are?
Let's have some fun.
You know, as I was talking to you before the show about when I come out and do classes,
you know, technicians don't have a lot of time out of the field.
You're always teaching the nuts and bolts, the need to know, get out the door.
We rarely get a chance to talk about the high level information.
And you know, we use the wrong terminology.
We don't really understand where this motor fits in, where that motor fits.
Why, you know, why are there two ECMs that seem to do the same thing, but they really
don't and all that kind of stuff.
And we've, yeah, we've talked about them in the different shows, you know, I can't believe
we're on the fourth show already.
It's been too much fun.
It's like when you go to your, you know, it's like you're headed to that ski trip and all
of a sudden driving home, you're like, wait, what happened?
So, so yeah, this is going to be a lot of fun.
I don't get to teach all this information all the time.
Some of it's going to seem a little rudimentary.
I am going to start out with some basics just to make sure we're on the same page.
You know, the terms of motors in the HVAC industry get confused and convoluted depending
on where you learned them.
You know, in the southern regions, in the northern regions, if you're a heat pump tech
or a gas tech, you may think of motors as evaporator and condenser or indoor or outdoor.
So I like the terms indoor blower motor and outdoor fan motor.
And when I start a lot of classes, I start here and say, just to make sure we're on the
same page, an indoor blower motor doesn't mean it's indoors, doesn't mean the motor's
inside the house.
It means that's the air that it moves.
It moves the indoor air from the home to the appliance and back to the home.
And it could be in a gas furnace, an air handler or a package unit, which means that the indoor
blower motor could be inside the structure or it could be outside the structure.
So yeah, so I just like to, you know, bring those terms in so that we're all on the same
page again, outdoor fan motor.
Obviously, it's the fan that moves the air across the condensing unit or evaporator coil
if we're in the heating mode of a heat pump.
So that could be a split system or package system as well.
And if you've ever worked on like a through the wall unit or a P-TAC for a hotel, you
know, that outdoor fan motor could be inside the structure.
So just just a little clarity in terms.
I don't know.
You know, you and you and I are both nerds of reading schematics and manuals.
And if you've read more than one OEM manuals, you've seen more than 10 acronyms used to
describe these motors.
And it's always fun trying to figure out what those three letters, what are they trying
to imply by IDM or whatever they've used?
So I always laugh.
Exactly, exactly, exactly.
So we're going to talk about HVAC direct drive fractional horsepower motors.
And again, you know, sometimes when you're teaching the nuts and bolts, you don't teach
these terms.
You know, what does what does direct drive mean?
What is fractional FHP mean?
Fractional horsepower simply means that these motors are rated in fractions.
Don't ask me why it includes one horse.
I guess one over one is a fraction.
I wonder.
But I didn't see that until you mentioned it.
Yeah, fractional horsepower motors includes everything one horsepower and below.
And then direct drive simply implies the type of drive it is.
So the whatever blade it's running, whether it's a fan blade, axial fan blade or forward
curve fan blade, that is going to be attached directly to the shaft.
The motor is going to be no sprocket, only a bling or a shiv in between the motor and
what it's actually driving.
It's going to be connected directly to that.
So just clearing up some terms and then oh, sorry.
And then the chart shows the typical horsepower ratings you're going to find on the indoor
blower and the outdoor fan.
This is kind of interesting because if you go back, depending on how old you are, and
I'm old, you know, back when air conditioning with it, when it was in its infancy and gas
furnaces were or had been around for a while, you saw quarter, fifth and third horsepower
motors in in gas only systems where you didn't have to move the higher amount of air that's
typically required for air conditioning unless you got one hundred and fifty thousand BTU
furnace.
Then of course you're going to need a larger motor.
But today and when I say today, my career spans 30, just we'll just say 30 years.
You know, you don't see too many quarter and fifth horsepower motors anymore in the indoor
blower category.
It's pretty much all third through one.
And since the invention of ECM, which is over 30 years as well, you know, you see a lot
more half and third half and three quarter horsepower motors than you do one and third
because they're programmable.
Right.
So I can take a motor of a higher horsepower and I can make it act like a motor of a lower
horsepower by programming.
And I can take a three quarter horsepower motor.
And depending on whether I need three fifty four hundred or four hundred and fifty CFM
per ton, I can probably get five ton of airflow out of a three quarter horsepower ECM motor.
So a little changing industry when ECM's were introduced.
And then in the outdoor fan motor market, the opposite shift has happened.
You know, it was very common 20 years ago to see third quarter, third quarter, fifth
horsepower motors.
And now, especially in your two and a half, two ton and one and a half systems, you're
seeing the sixth, the eighth, the tenth.
I even saw a 12th horsepower PSC motor the other day.
Darn thing wasn't more.
I mean, it was like an inch thick.
It looked like it looked like a ceiling fan motor.
So it was interesting looking.
So so yeah, there's some of the ways the industry has changed and some of the terms that we
use.
So there are basically four types of motor technologies used in fractional horsepower
HVAC.
And those include permanent split capacitor, which the acronym is PSC.
We will talk a little bit more about that.
You've got constant torque ECM and then constant airflow and then constant speed, which you
announced at the beginning of the show.
If you haven't if you haven't caught the previous three shows, we've we've done a special on
each one of these shows.
So are each one of these motor groups technologies so you can watch those webcasts and learn
all about those motors.
But the most common application of these motors is kind of interesting.
I often get asked, well, how do you know that a constant speed motor?
Well, because it's in the outdoor application.
Well, how do you know?
It's just where the industry has landed that technology.
They don't the industry doesn't typically apply a constant speed ECM to an indoor blower
motor.
Conversely, the industry doesn't typically use a constant torque programmed motor as
an outdoor fan motor.
So you find constant torque and constant airflow in the indoor motors and constant, excuse
me, constant speed in the outdoor motors.
And we're going to talk about that at the end.
We're kind of kind of wrap back up with that.
That has a lot to do with the the air it's moving and the type of blade it's turning.
So whether it's a forker fan or an outdoor fan, the programming, constant torque, speed
or airflow, some some of those programming methods work better with different types of
blades and under different types of loads.
So that's a little little teaser there for the end of the presentation.
I also wanted to work in a little bit of history because I think I don't know, maybe it's just
me.
You know, I got I got older and I became a history nerd.
I wasn't really a history nerd when I was a kid, but history became more human.
I got older, you know.
But it's it's interesting if you watch this progression and it's sort of interwoven in
the presentation.
It's sort of eye opening where ECM's came into the industry and how much earlier they
were around before most people thought they were in the industry.
So if we focus on the indoor blower motor side of the industry and we talk about new
equipment built and we go all the way back to 1986 and there's you'll understand why
I chose 1986.
It's not just because I graduated that year, but we go all the way back to 1980.
Look, giveaway there, all the way back to 1986 and in the indoor blower application
of new equipment, the number one motor used was a PSE direct drive motor.
Now I know there's somebody that's out there saying, oh man, there were belt drives back
then and there were still some shaded.
Yeah, there were some belt drives and some shaded poles.
But the primary motor technology and HVAC equipment in 86 was a direct drive PSE motor.
And it doesn't matter if it was a air handler, fossil fuel, package unit.
That was the technology.
And the reason why I like to go back that far is a couple of reasons why I like to go
back that far.
It helps understand the integration of ECM, but also because we did we did three webinars
on ECM motors and we talked about PSE motors for probably a collective five minutes.
Yeah, not a whole lot about it.
I mean, it was not a whole lot about it, but yet there's still the largest volume of motors
used in residential HVAC today.
And in tech support, I'm reminded every day how much how many contractors have have not
been taught as much about PSE motors as they have about ECM motor.
So it's just going to take a little bit of time here.
Go back and talk about the PSE motors.
PSE again stands for permanent split capacitor.
It's an induction motor that uses an externally connected run capacitor to help with its starting
and provides additional efficiency.
You can identify it a couple of ways.
You can physically see it, follow the wires out and hey, what's that silver thing?
That's the cap.
And that's oh, that's a PSE motor.
Or you can look at the schematic on the motor.
You got a little pictorial there showing you the cap.
And you can see in the ratings where you've got the microfarad and voltage ratings of
that capacitor.
You can't I'm sorry every time PSE motors come up, I always have to say if you're ever
replacing a cap, make sure you replace it with the rating on the motor, not with the
rating of the cap that was there before.
Always check the always check the rating on the motor.
Sorry, little little plug for proper.
This is all educators know how to relay this to the classroom.
This is all stuff that could be potentially missed.
Yes.
So if we switch to the outdoor fan motor again, just talking about I know we're in the indoor
blower motor category in our in our history lesson, but we're in PSE.
So we'll talk about the outdoor fan motor PSE as well.
Again you can see the run capacitor out here.
Most commonly in the outdoor unit, it's a dual run capacitor.
So you've got a single common terminal with an F terminal for the fan motor and an H terminal
for the compressor.
I know H doesn't go with compressor, but it does if you know.
Yeah, hermetic.
There you go.
And then you can identify it by the diagram on the side of the motor as well.
And again, the rating on the motor.
So PSE motors commonly built in two sizes, either six pole or eight pole.
And that's important because the blower wheels and fan blades that were used when PSE motors
were king and again, they were king up until just a couple of years ago.
Fan blade and indoor blower wheel for PSE motors had to be to 825 RPM because those
were your high speed RPM values of six pole and eight pole motors.
And with PSE technology, we're not going to drill all the way down to the amount of poles
times the frequency divided by two.
But the poles and the frequency determine the RPM.
If you want a motor with a significantly different RPM, such as going from 1075 to 825, you have
to get a completely different motor.
You can't run a 1075 motor down at 800 RPM.
You can, but it would be horribly inefficient and creating a lot of heat and probably wouldn't
last that long.
So that information will be very valuable when we progress into ECMs and understand
the value of ECMs being programmable.
But yet the fact that ECMs were used with the same blower wheels and fan blades that
used to be used on the PSE motors and why they still operate around those typical 1075
and 825 RPMs.
Because the wheels didn't change, but the motor technology, the wheels and fan blades
didn't change, but the motor technology did.
So you've got indoor blower motors, typically multi-speed.
They're multi-speed because quite often you've got a airflow requirement for the fossil fuel
appliance that is different from the airflow requirement for the outdoor unit, whether
it be AC or heat pump.
And then you've got the outdoor fan motor, which is typically one speed because it's
engineered by the manufacturer to run at the one speed necessary.
Again, we're in 1986.
We're talking about single stage equipment.
Very good.
Good.
Good catch there.
So, you know, one speed it's been engineered to operate at the one speed that maximizes
the condenser TD across that coil.
And that's what it does its whole life.
So very simple motors.
The average efficiency of a PSE motor is around 60 to 70%.
They often get a bum rap.
They often get, they often, oh, there are 60% efficient motors.
Outdoor fan PSE motors can get up as high as 70% because they are optimized to run at
the most energy efficient RPM range of a given motor with a different load in a given system.
So when you, when you pick the RPM point on the, on the performance curve that is the
most efficient and you design your blower blade around that, then you can get quite
a bit of efficiency out of a PSE motor.
But when you're using multi-speed motors, the challenge with multi-speed motors is when
you blow a PSE motor, any induction motor down below its synchronous speed.
So I said we wouldn't dig too far, but a six pole motor synchronous speed would be 1200.
So any speed below that is moving away from its synchronous speed.
The further you move away from synchronous speed by going to medium or low speed, the
more inefficient the motor gets, the more heat it creates because the less mechanical
energy it's creating.
So multi-speed motors have these extra windings.
And so we, you know, we add resistance, more resistance, less amperage, less amperage,
less torque.
So, you know, we've, we've called these motors multi-speed motors forever, but technically
they're multi-torque motors.
As I reduce the amount of torque the motor can generate, blower wheel slows down and
the speed changes.
So, you know, going from the high speed to the medium speed, which is really going from
the highest torque capability of the motor to the medium torque capability of the motor,
I slow down in RPM.
So we call them multi-speed motors.
It's kind of tomato tomata.
It means the same thing, but I use this as the setup for the next motor we're going to
or the second motor we're going to talk, third motor we're going to talk about, which is
constant torque motor where we're going to start to understand that ECM motors absolutely
focus on torque and speed or just torque.
They're not multi-speed motors at all.
Why go back to the PSC motor and say, well, they really never were.
They're multi-torque motors that run slower when you go to a lower torque value.
I'm glad you represented it that way.
Cause I actually haven't thought about that from that perspective, but a hundred percent
it when we change a resistance, we're changing the capable torque of the motor consequently
changes the RPMs of it.
Yeah.
And another thing that is kind of interesting since you gave me a pause there, you know,
you know, when you're teaching, your brain's going a mile a minute.
Sometimes you stop and you think of something else.
You know, we're going to, when we get to the ECM, we're also going to understand how one
motor can be more than one horsepower very easily by programming.
And I don't need to build many different motors to do one thing.
In other words, I can have one ECM that takes the place of five ratings of PSC motors because
of a wider operational range and the fact that it's programmable.
I can tell the motor what torque I want.
I don't have to actually tap the winding.
So a PSC motor, let's say, let's say on this PSC motor, what I really wanted was I wanted
a torque that was right about here.
Right?
Well, I can't do that unless I'm going to, you know, do a YouTube special and open up
a motor, break the windings open and what, and solder a wire in there.
I can't get that torque value.
It's been built, you know, with the windings tapped here and here.
But with an ECM, I can program it to give me that torque value or that torque value
or that torque value.
So I really open up the capability of a motor when I have programming versus tapped winding.
And a tapped winding motor, it is what it is.
It's never going to be anything else.
Hmm.
Okay.
Great way to explain it.
I'm sure there was a lot of teachers out here going, okay, all right, this makes sense.
This is the way you deliver my content now.
There you go.
That's what we're shooting for.
The other thing that I think is kind of interesting and this, I can hear five or six people out
there yelling, that's not right.
You know, a PSC motor really only has a value in HVAC in forward curve fan systems and even
in an outdoor fan system only has a valuable operating range of about two to 300 RPM below
its rating.
So let's say you have a 1075 RPM motor.
It's really only good to around 850, 900 RPM, somewhere in there.
Because once you start slowing the motor down below, and you can operate it lower than that,
but you operate it at an extremely inefficient place where it could be running less than
30% efficient.
And it's going to be, because it's not generating as much mechanical energy at the shaft, it's
going to be creating a lot of heat.
So you're probably going to have a significantly reduced lifespan.
So I'm not saying they can't operate below that range.
They're just, they're valuable.
Their long-term operational range for efficiency and longevity is two to 300 RPMs less than
what they're rated at.
So there again, if I want one motor to operate from say 600 RPMs all the way up to 1200 RPMs,
can't do it in PSC technology.
I'd need two motors in a system.
And interestingly enough, me and another trainer at Regal Rection, we asked the engineers once,
well, couldn't you build one?
And just for fun, they actually did build one.
They built a multi-pole motor, all in one motor.
And it was half horsepower.
So this is a half horsepower ECM.
It was half horsepower, but it was this long.
Because it literally had to have two sets of windings.
And it had like 16 wires coming out of it.
It was really and truly the family truckster.
It was nasty looking.
But it was...
It had to do a replacement universal.
Yeah, but it was truly a six and eight pole motor, all in one casing.
Man, 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.
Have a great time.