PSC Motor vs Constant Torque Motor vs Variable Speed Motor | Comparison Video
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- Опубликовано: 9 июл 2024
- This is a comparison video of a PSC Motor vs Constant Torque Motor vs Variable Speed Motor. We will explain what a variable speed motor is, and how it is different from a constant torque motor. We will also discuss the difference between a regular permanent split capacitor motor and an ECM motor. I'd like to discuss the benefits of a constant torque motor and if it can save money for you.
PSC motors are simple, fairly inexpensive, moderately efficient motors with a reputation for being loud and not very dynamic. They also come hitched with the always unpredictable capacitor, which can go out due to overheating.
ECM constant torque and ECM variable-speed motors are pretty complex in design, high-efficiency motors, known for being much quieter on start-up and shutdown. Their ability to control airflow better than PSC motors makes them smart motors because they can ramp up power as needed (the variable speed more so than the constant torque motor.) All of this comes with a higher price tag, though, when it comes to repairs.
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00:00 Intro
2:18 PSC Motors
4:47 ECM Constant Torque Motor
8:42 ECM Variable Speed Motor
12:10 Conclusion 
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Great explanation of the motor types. You covered exactly all the things I was wondering about.
This Gentleman is giving a lecture at an academic level equal to a professor at the graduate level.
Excellent explanation of these three types of motors. I am an HVAC instructor for a college HVAC course as well as tech support for HVAC technicians. This is the best overall explanation for these motors I have heard.
That's great to hear! Thanks so much.
The ECM in our furnace failed over Christmas while we were out of town. The service company would not honor their lifetime warranty sold to the previous owner, but the technicians showed me the small, overvoltage protection device had failed, shutting down the motor. They wanted more than $1000 to replace the entire motor plus controller assembly. I told the technician I would have to think about replacing the motor. I paid him for his service call and then ordered the new part online for delivery the next day. The part arrived, I took out the remains of the failed part, soldered in the new part and it has been working fine and for the last eight years. I spent $35 for the part and shipping. I got a spare just in case the part fails again. I wonder how many people’s financial lives fall apart because they can’t make a $25 repair of something that is essential to modern life.
The part which failed was a surge suppressor in which research indicated a vulnerability to power cycles and surges. The explosive failure of the part coincided with a power outage and subsequent restoration. That were very likely to have caused voltage surges. I have sense installed a whole house, surge, suppression device at my electrical panel.
Also called a thermistor. A black round disc with two wire leads that solder onto the circuit board. You can also purchase only the ECM part on those motors however, the cost is almost the same as a complete ECM motor ! Likely a poor quality part vs. "power surge" since many of these fail.
I went through the exact same thing with our Bryant furnace like 10 years ago. Got lucky, and since I have a basic understanding of electronics, found that MOV looking disc in the motor popped. Found replacement for like $3.00 and replaced it. Motor came back to life and still running! Shame to think about all this stuff just thrown out because of a part that cost a few dollars. Also learned that the actual motor is a 3 phase permanent magnet motor and could be used as a wind power generator for a hobbyist!
Bravo. It's disgusting how averse not only regular people, but even the so called technical experts we call for help are, at making repairs. I guess our litigation-obsessed society is at least partly to blame, liability and such.
Good video, but you got the PSC and ECM amp draws backwards. PSC motors love high static and restricted duct work, they draw less amps and deliver less air because they are one speed only High, Med., or Low. depending on how they are wired. So, when the ducts and or coil are restricted the amp draws will be less on a PSC compared to a ECM. However, the exact opposite happens to the ECM because they are constant torque, and always will ramp up to deliver the programmed cfm, they will pull more amps with restricted ducts while trying to deliver the right amount of CFM. In fact, this is one reason ECM motors don't seem to last as long as a PSC, when they have restricted ducts or coils they are running at much higher rpm's, basically max rpm's and pulling max current, which makes them fail prematurely.
In the past this was a dirty little secret, where the contractor would put in a variable speed motor to overcome duct work problems, sacrificing efficiency for better airflow, instead of fixing the duct problems. Now, because of the FER Fan Efficiency Rules we have to use a ECM motor on almost all systems. So, it is imperative that you take a static pressure of the old system, including a duct leakage test to determine duct work problems and fix the ducts before replacing that old PSC system with an ECM. Otherwise, you will be back out in a few years replacing a motor that costs over a thousand dollars.
Good video
Thank you as always Mitch! You going to the AHR Expo this year in Vegas?
@@foxfamilyheatingandaircond4696 Wish I could, but I have to teach classes in Tulare at SCE the 1st and the 2nd of Feb. I also signed up for teaching for NCI next year, so far I have over 60 classes I will be teaching next year between IHACI and NCI.
@@baileysair Wow. That's awesome. Thanks for all you do for the industry.
If a motor fails prematurely because it actually needs to run at its full nameplate rating, then it's a crap quality motor. Period. That excuse would never fly in any other industry.
@@peterl1365 Thanks for your comment. However, it's not the motor that fails, its the powerhead. As you know capacitors fail all the time and that is usually an issue with heat, too much heat and you let the smoke out. The same holds true to the electronics that control ECM and Variable speed motors. They just don't hold up to running with extreme static, it generates to much heat in the powerhead electronic components, the motor is fine, its the powerhead that fails. Granted that is not an excuse. However, as I have been taught it's all airflow, airflow, airflow. When airflow is bad you will never get the capacity, efficiency, longevity, and or the comfort. Fix the airflow and the motor will last longer, plain and simple. Here is a link to a great video by Grayfurnaceman. ruclips.net/video/XfGHC1O9ryk/видео.html
Great video man thank you for the knowledge , been hvac for 2 years now got a lot to learn
PSC motors draw fewer amps under high static / restricted conditions
The Split phase refers to the fact that the capacitor creates a phase shift which creates a difference in phase angle between the run and start windings - residential power from the utility, regardless of voltage, is single phase there is no phase difference between the legs; just potential difference
That's it. Although it's fair to say that the two hot lines in a single phase system are 180° out of phase with each other with respect to neutral.
@austindillon443 Yea but once the PSC motor heats up from the lack of air movement it would start to draw higher amps no?
@@Duck1cVE Peehaps if the airflow were restricted severely enough but I have never seen that be the case. You can install an amp or watt meter on a unit with a psc motor, restrict air flow and observe for yourself that the amperage/wattage decreases
@@austindillon443how it can decrease if it has to work harder . It’s electric device and they are all the same. Overcharge the compressor and watch your amps
@@MrBlinchikON Your answer is in your question. What happens when static pressure goes up? Airflow goes down. The work, or load, on the motor is the volume of air it is moving. So, as static goes up, airflow goes down, load goes down, amps go down. You can test this with a watt meter or you can take my word for it; it’s correct
Cost of ownership plays an important role for most folks I believe. If a variable speed motor is going to be 4 times the cost of a PSC, it does make one wonder if they want that supposed to be "20%" savings and less noise. It also is important to know that those higher end motors have PCB, circuit boards, with solder joints, printed circuits and electronics on them that will also likely find more break downs vs. PSC. Sometimes it is best to stay with old reliable and focus on other mechanic parts that can be more efficient that don't have a short or limited life cycle. We all know that much of today's parts are made with less quality, robust and longevity in mind so a $750 motor replacement once seems more interesting than a $2,800 replacement likely three times during an HVAC lifespan.
True but according to Dave the pool guru at pool tips chanel, he hasn't had to change one variable speed motor for like 15 years, and they all say.80% to.90% electric savings which I'm still trying to verify bc of true, variable would be way cheaper over 3 years
@@SmedleyButler1 Are we discussing Pool pump or HVAC motors?
The older versions of the Genteq X13 ECM motors found in condensers and blowers were the worst of them. The ECM has a "thermistor" which is a $2 part that regulates in rush current is soldered onto the circuit board and in most cases, not all, that part fails while the rest of the mechanical motor parts are still good. The latest replacement for them is the Evergreen ECM which doesn't need programming and tends to be more reliable. Still, those motors are 3X the price of a PCM replacement or around $600.
Huh? X13 is not variable speed... the constant torque and inability to self-regulate means whenever there is an issue, that issue sooner or later results in the motor burning itself out. Variable speed have much better durability. IF for whatever reason the motor dies early, that ruins the equation, but that's why warranties exist. They're also not so crazy expensive as suggested here. @@Garth2011
@@garrettmillard525 About $900 some are $600 such as Evergreen. PSC are $150 to $225
@@garrettmillard525Yes, they are.
your knowledge and detailed explanation is greatly appreciated. i learn something from every one of your tutorials.
The incredibly high quotes I've gotten for repairs or new systems made me so angry... I now own all the special tools (bender, swager, gauges, recovery unit, scales, probes, brazing etc..) Educated the crap out of myself, became certified for the gasses and now perform 100% of my own work. My systems in my homes perform perfect with exact humidity/air/temp control and my repairs cost little to nothing, even ECM or full VFD 3 phase motors, I am also a high and low voltage electronic controls expert, that helps a lot. My variable speed systems are all 3 phase VFD driven with single phase inputs, now were talking my language.
I'm a retired electronics technician, the short lifespan of our parts is due to "designed obsolescence" from a short sighted type in Detroit, AND capitalism's insane allowance of allowing limited resources to be wasted in lousy products imo. I would like to add more restrictive filtering to my furnace blower motor. Ive ordered a manual D, and considering a bigger psc motor, thanks to your honest cost assessment. Thank you for a good video.
Very good knowledgeable, educational explanation and topic coverage Included in this Video. Great Job.
Capacitor takes the place of a shaded pole and provides the 90 degree phase shift needed for a PSC motor to turn. It is pretty cool seeing it in an oscilloscope.
Don’t forget the start winding.
Also a capacitor is acting as if the power were 3 phase.
@@Garth2011 2 phase. --Doozer
@@picklerix6162 2 run windings, supplied phase and offset phase. --Doozer
@@kooldoozerCorrect. My error
Good video but your description of the PSC is not correct. The utility does nothing to operate this motor other than supply the operational voltage. The utility does not "split" anything. It is the capacitor that provides a shift in the phases between the two windings, thereby allowing rotational forces.
Very good explanation!! Thank you
Nice explanation: However I don't know any tech's that carry both parts of an ECM motor. Most of them change the whole thing and not split the motor and change the affected part. One replacement will wipe out all the savings that ECM motors may have produced.
Good points. Thanks. Yeah I can never remember changing just the motor part. It seem to always just be the module which had to be ordered from the factory.
I once saw a module only get replaced on a rooftop package system. In this case the thermistor had failed on the module.
Good point and I hear what you are saying. When selling and installing these motors I try to let the customer know they are paying for the added comfort they provide more then anything else.
👍👍👍
Thank you for all your videos they help a lot , to have a better understanding of the systems and trade 👍🙏🤝👏
Thank you!
S-Split, comes from Phase Shift that takes place in a stator winding set perpendicular to the run winding in the stator. It is less inductive than the run and in series with a capacitor. The combination of the ANGLE and capacitors leading current "Shifts" and "splits" the phase and attempts to achieve an optimal 90deg shift.
Great video and information 👍🏻
Another good, informative video!
Excellent lecture!!
What a great video! Thank you so much for sharing so much knowledge. Does a variable speed ECM motor is supposed to run constantly? ( on hot days)...?
Great video!
Great video. Thnx
3-4 weeks ago I read your posts about insulation in vents. I had same problem . Brother in law said i was being neurotic thinking it was from animals. Well it was Rodents--- MICE in particular. Had H/V Guy over to fix ducts, & exterminators over for MICE. Thanks to your post I stuck to my guns knowing something was Wrong. Always go w/gut feeling & thanks to you guys problem solved!!!
Best explanation ever.
Thank you for saying the cost of repairing ECM motors really isn't worth the savings in efficiency. We all know when those ECM motors fail in 10-13 years, we are the poor saps that have to tell the equipment owner they have to fork out tons of $$$$$$ to fix it. Every owner was totally shocked to hear this. They couldn't believe it.
Yeah. It really is.
10?😂😂😂 Most of them failing within the first 5 years, it's ridiculous how sensitive they are to static pressure and voltage spikes.
They are trash!
This video was great & helpful. What needs to be changed when converting a PSC motor for an ECM?
Very good video…
Wonderful explanation but what about CSCR motor? does it go by the same name you went over?
Thanks
Nice vid, and I have a silly question. When I replaced my furnace I was told that it is a variable speed unit, but after I had it replaced I found out that I can't use thermostat to set fan to run low or high. My new Carrier furnace + heatpump uses a ECM motor and is it even possible to replace just the blower motor to enable me to have a low/high setting on fan speed? (eg. Sometimes I just need fan running to circulate and no need for cooling/heating). I think that's somewhat misleading saying the system is variable speed when the blower only runs at 1 speed whenever it is turned on. Thanks in advance.
Good info!
The difference is price not worth it tho. Psc all day .....
👍👍👍
Double Dip Amen
I looked at the prices in your chart. Those prices seemed awfully high to me. The last time I replaced a blower motor a generic 1/3 or 1/2 HP motor was under $50. Well, I just checked Amazon and those motors are $125 to $250. And, Grainger's prices run into the $500 to $600 range.
Your right.... if a slave puts it in for you😂😂
Those are prices for the contractor to install, not the homeowner
you are a true HVAC instructor! Great Job!
Is their anyway to get it to run without 24v? I have 1 im trying to make a fan out of
Most extractor fan motors I have come across are PSC. Speed controllers (Triac) are available but it is recommended to feed the capacitor (therefore the aux winding) with a permanent live instead of from the controlled output of the controller. (This is 3 wire connection). Why is this ? I assume to create more torque at low speeds but I can find nothing to confirm this. I've also heard the aux winding in a PSC draws almost no current when running at rated speed. Is this correct and why?
To say an ECM motor replacement is priced around $3k is an indictment of the whole HVAC industry. We are probably 1-2 decades behind where we should be in the area of efficiency because local installers are too comfortable with old technology and manufacturers mark up efficient models and parts way beyond the extra manufacturing costs. I put in a furnace with an ECM motor 15 years ago and it was a great decision - a noticeable decrease in my electric bill, much quieter, and my old home has significantly fewer cold spots on cold days. Anything less shouldn't even be on the market any more. I'd hate to think of where we would be if the government wasn't pushing this industry forward.
You want everyone to have a heat stroke. Socialist. One size never fits all.
@@marshmower What I want is to be able to affordably install the most efficient, advanced, and comfortable heating and cooling system available the next time that I need an upgrade done. I'm sick of local contractors trying to push 50 year old technology on me in the guise that it is more reliable. I'm sick of manufacturers artificially jacking up the cost of modern, advanced systems - whenever they eventually get around to offering some. The industry is failing to offer affordable, modern systems to enough people. I don't care how it is improved and I'm perfectly happy to have government push them into the 21st century if that is what it takes.
Good vid !
Thanks OC!
Thank god my system is still under warranty and had my ECM motor replaced. The motor worked but it would turn itself on by itself even when the system was set to off.
Give me a good old-fashioned PSC any day 😁👌
Is the Dwyer magnahelic or liquid gravity the MOST reliable static pressure gauge?
New eco motor complete with install is $430… not thousands or am I missing something
A circuit board on the end of a motor is the stupidest thing. I'd avoid that crap. I get it that it is CYA not having a modular drive system. But usually anything that's all-in-one is usually junk. Component level and modular with some color codes or electrical ratings that are compatible would be nice. I'd imagine industrial applications have separate three phase drives. And those have to be sized 1.25 times the FLA. I know someone trying to rebuild a speed control "head". This is news to me. We gotta fight this crap. Well i appreciate all the info and hope things get simpler before everyone just buys a window unit.
Great explanation on motors. Can you please reference the tool needed to test the variable speed motors?
Nice job I'm from edmonton alberta Canada
The more I watch your videos the more I just want to start my own business
very cool man thanks, very well explained.
Thanks.
You’re never gonna notice the efficiency or energy savings on the newer motors on your bill. It’s just the nature of the beast. Everything is going more energy efficient. Do not expect to save any measurable amount of money.
11:30 when bro has the same notification sound as my on call phone. Its like ptsd hearing that
Great Job Sir. Thank you. My Constant torque motor 's control module went bad. Can I use the motor (the machanical portion for other means than an AC blower motor? Will the motor actually work and turn without the control module? If you know of a website that speaks of this in detail, can you please link me to it. Thank you again.
No you can't. The control module is an integral part of the motor the windings are energized sequentially by the module itself. Without the module, you just have a bunch of disconnected windings.
The capacitors on PSC motors used on compressors and fans on outdoor HVAC condensing units are always energized on most units. There is typically only one contact that opens that prevents the unit from running, but the other 120v feed is always energized. Does this arrangement actually contribute to wearing out the capacitors?
The caps will maintain their "charge" after unit shutdown unless "bled" intentionally or if they have a built-in bleed resistor (across the contacts) but otherwise they are disconnected from the power source during a unit shutdown. I believe that cap failures are most likely due to inferior manufacturing (Made in China), after all they are a passive device. Of course improper sizing (specifically lower voltage rating than required) is a sure way to shorten it's life.
Certainly the fact that the outdoor units capacitor sitting out in the summer heat while running does contribute to why they don't seem to last long in warmer climates.
If you live where there is humidity there is nothing like a variable speed wired to a humidistat. Although for arguments sake we have wired many psc motors to a humidistat through a no nc relay and this does work just as well. But for simplicity's sake the dehum terminal on a variable speed makes it easy. Good video, Thanks
I live in Florida and many seem to say its almost pointless to have a blower with a terminal for a humidistat, unless you also have a 2 stage blower. Is that really true? My thought is that if the blower then lowers CFM by say 60-80%, then it can lower humidity, at the expense of running longer (makes sense) and then I would think it would not bring the overall temp down much, verses most where it will end up lowering the whole house temp by several degrees, depending on humidity.
@@senecapierson9092 Ok so I don't know who "many" are but I can tell you from experience that variable speed blowers with a dehum terminal on Allied equipment cut the airflow back to 75% when deenergized. This allows for lower evaporator temperatures and longer contact time with the air passing over the coil. They work extremely well and will automatically go back to full fan speed when the set humidity is reached thus giving you your advertised seer rating. So just to make a few points clear both variable speed and constant torque motors are ECM but the constant torque is the cheaper version with no provisions to vary the speed. The variable speed blower has a mofset controller that allows you to vary the speed. When you say a 2 stage blower you are referring to a two stage furnace or air conditioner that will automatically change the blower speed to the level needed for the stage being operated, these can be either ECM or PSC multi tap. Ok so without getting into all the details you will still have the same BTU output as that is controlled by the size of the compressor you have, not the airflow. While it is true that you will have less CFM of air, your air will be colder. If you dont have a variable speed blower with a dehum terminal you can get the same result by installing a no nc relay in your air handler and adding a humidistat. Just place the small 24 v relay between your cool tap on the control board and the normal speed wire to the blower through the nc output of the relay. Then tie the NO of your relay to the speed tap that is a lower speed. Then run 24 volts to the humidistat and have it send 24v to the relay coil when the humidity is above your setting, this will energize the relay and have it switch to the lower fan speed. You can do this relatively cheap for just the cost of a 10 dollar relay and a 25 dollar humidistat. This will allow you to see how effective this way of dehumidification is If you dont have a anemometer or a performance spec on your blower I would drop 1 speed tap at a time and measure superheat. You dont want to drop the speed so low that you send liquid back to the compressor. What you are going to lower when it is dehumidifying is SEER rating not output. Once you see how well this works you can make a better decision on the equipment you replace it with. PSC motors do cost more than ECMs to operate. Hope this helps
@@anthonyspadafora1384 Yes, sorry, I meant 2 stage condenser not blower. Most around here seems to say for proper control, you have to have a 2 stage condenser at least.
But yes, overall it helps. I have had 4-5 quotes here and just get all kinds of different answers, from "reputable" HVAC companies.
Currently I have a 2ton 13 seer heatpump and 2.5ton blower, Carrier, 20 years old (R410). Not going to a new system for higher SEER as I will never get the money back in increased efficiency, even if we went to say 20 SEER over say 14-15 SEER.
So what you mention then may not be bad then. I do have a Thermostat that supports accessories and such such as dehumidifying, though I believe I only have 6 wires in the bundle to the thermostat, and all are being used right now. So I would need to pull a new wire, which is not that bad to do.
So basically I am looking at a Tempstar blower, being either a 3 tap, 5 tap ECM, or variable speed. I believe only the vairable speed has the terminal for dehumidifier, and I believe the spec sheet/install sheet said when its on, it cuts CFM by 80%. And then then we would have a single stage heatpump. The 2.5ton air handler is just oversized for my house, however because of windows, insulation, etc. humidity usually stays between 40-55%. I just figured, if spending money on a new install, if for a reasonable amount of money, I can gain better humidity control, where I can keep it at say 42% or so all year, that would be ideal, but again, to do that without actually lowering my overall temp. I tend to keep the house to say 80 in the summer, with a 1 degree swing, and then 70-72 in the summer. Efficiency I am not overly concerned about because I know my old systems with a bad TXV value is just going to be pretty inefficient now, and then that it was oversized (the returns were also above the baseboard, we had them moved to the ceiling when we had the flex duct replaced a couple years back), which makes me feel it was someone who moved from the north east and designed it how they would have up there.
So if I follow you, and on say the 3 tap model, if I used the medium speed all the time, then that and the low speed would go into a relay where its "default" on say medium, but when the thermostat is calling for humidity control, it then triggers the relay which then changes the speed to low? And that should not have much impact on the blower for when it changes between medium and low and back?
@@senecapierson9092 That is correct how the relay works. One other thing I would like to point out is when in the air conditioning mode you should keep the fan on the "on" position especially if you live in a 2 or 3 level home. Usually the thermostat is located on the first floor and the cool air from the a/c will come down the stairway leaving the thermostat satisfied and the upstairs considerably hotter. With the fan on, the condenser will still cycle according to the thermostat but air inside the home will constantly be pulled into the returns and redistributed throughout the house. This will allow both floors to be closer in temperature. With a variable speed ECM blower the unit will also have a circulating speed which it will switch to when the stat is satisfied. This low circulating speed is very cost effective and very quiet and returns to the proper speed when there is a call for cooling.
@@anthonyspadafora1384 Yeah, so I am in a single story 1280 sqft block home, in Florida. So AC runs most of the year, with heat on when needed in winter (hence the heat pump).
Basically I am just debating between 3 different air handlers right now for the new system, 1 being 3 speed PSC motor, another being a 5 tap ECM motor, and then the third being a variable speed motor. I am not interested in spending more for a 2 stage condenser as there will never be even close to a payoff in efficiency/$$$ for us. The full variable speed blower I believe he told me would be $500 more. Not sure on the 5 tap yet if that would be say $100 or $200 more.
I do appreciate the insight though. I did not see anyone else online make that recommendation for humidity, basically being able to turn a 3 speed PSC blower into a "2 stage" blower. Being in a high humidity climate, like today, where the AC has not ran, and its now 57% RH inside, if I had that relay and a compatible thermostat/wring, then it could kick on AC, run it on the lowest CFM setting, and bring that RH down to say at least 50%, without really lowering the homes temp then. Thats really what I am looking for, without "breaking the bank".
My variable speed motor module went bad in my Trane XV90 Unit. But for some reason I can’t buy just the module, I need to buy the whole motor. Part alone was pretty pricey. Not including the installation fee. Sucks but what else can I do, Gotta bite the bullet and get it fixed. But thanks for the knowledge on the three types of motors.
Do you have anymore videos specifically on variable speed motors? Great video
I don't, sorry
Very nice explanation. I wonder, though, why doesn't the industry use more conventional AC induction motors with variable speed frequency drives. The cost of the these should be very competitive in fractional HP sizes. I seem to recall 1hp VFDs selling for just a few hundred dollars, and that was 10+ years ago. The pool pump industry has VS models that sell for less than 1500 at retail.
Even though one could easily control the speed of a three phase motor there is very little significant difference in the efficiency of the three phase motor over the PSC. Because of that they would still have to go with an ECM motor because they are 80% efficient. There is slippage when using a PSC or a three phase. No slippage with ECM.
@@jimthvac100 I agree with you about the slippage, but the efficiency hit is not that great, particularly with FHP sizes. I'm talking more about cost of replacements. The components should be much cheaper, but they are not. I'm guessing that the actual manufacturing cost of ECM motors and drives is actually lower than 3phase motors and inverters, but they are sold at very high prices because the end-user has almost no leverage when needing a repair. In other words, I think the industry may be guilty of price-gouging.
Not sure you fully understand how these motors work. An ECM motor is actually a 3ph motor with a module attached to the back that converts 120-240vac to 3ph AC like voltage that can modulating hz to control motor speed. The savings in ECM vs PSC motor is that an ecm motor can ramp slowly to its required speed not drawing FLA during start up where a psc just kicks on drawing excesivly hi amperage to get going then settles down to run load amperage and stays there. Another savings with ECM Variable speed motors is they can ramp up or down to provide only the nessesary air volume at any given time. Meaning on a multi stage high efficency unit it can slow down the fan, the compressor, the cu fan motor all at the same time when the thermostat gets close to set point and continue running at a very low amp draw while also making a much more comfortable environment with assentually no temperature swings. The slower the motors operate the less amps they draw. A psc just starts and stops drawing a lot of amperage on each start up and then continues to draw the same RLA until the stat is satisfied. The start up of a psc on each call for heating or cooling is where the majority of the energy is wasted. But if you were to leave the psc motor on all the time you would also waste energy as the fan is not needed all the time even if its running at a lower RLA draw 24/7.
The cost of a small drive will still be around $500-700 then you will still need a speed reference to run the drive at the desired speed and since you dont have a BAS building automation system you would need some kinda of fance control board withbstatic pressure sensors I/o to operate the drive and motor so another $1000-2000, then you still need the motor another $100-200, breaker or fuses to protect the drive $75-120. So at munumim thats $1600 before installation costs. So its currently about the same costas the current residental ecm set up except the current ecm setup in residental is way more compact and actually fits inside the ahu nicely. As time progresses these ecm moters and tech will come down in price. They are pretty much standard in all new equipment being sold now lower models have constant torqe motors and higher efficiency units have variable speed motors.
Great vid thanks
With over 15years in the field diagnosing and repairing furnace and heat pumps... ECM and Variable Speed motor have a high failure rate.. and its almost always the control board on the motor that fails.
I have a PSC Rheem air handler RMSL, can I have the motor & associated upgraded to an ECM Variable Speed Motor?
I think ecm's are crap.
If you get one.....make sure your intake vents are actually properly sized or the reduced airflow will cause the thermistor to blow and it's not replaceable due to some epoxy crap they put in so it ends up costing you big money for a total motor change.
Most anything tied to Government approved is NOT going to carry any value to the user or owner. In the above examples, The cost of getting efficient results is a huge up front cost and there is no guarantee that those efficient motors are going to run for hours and hours or weeks on end that will yield the payoff. Just one breakdown with those ECM motors will take away any savings they gave from the past usage and dig into any future savings. If they are not built to live long and be durable like the PSC motor, then they are not worth the extra cost given the price of electricity remains equal. We will find out much about reliability if the state of CA forces society to spend much on the ECM systems especially the heat pump debacle. When those motors are used twice as much, wintertime and summertime, we will likely see ECM motor replacements increase which overall will pass the trash onto the good public. It surely doesn't seem to be a free country if our Government is moving into our homes and requiring "efficient this or that" without regard for the cost to "upgrade" and convert homes from gas or LPG to all electric. It also doesn't makes sense to require residents to make these conversions without proof that the changes to a specific location/residence are going to result in anything better in the emissions department. Electricity has to be produced/generated somewhere which means emissions are not getting eliminated, they are being moved from a neighborhood to where power is produced. Not to mention, the cost will very likely double or triple which will make simple electricity unaffordable to the common people.
The only way going ECM would make any sense is...as long as someone else paid for them and maintained them and huge numbers of EMC motors were in operation, most of the benefits would be to the power grid. One on one gains aren't enough to make the expense worthy to just one address while millions of them will benefit the power grid but without any rate discounts from the power companies for using ECM motors, there won't be a lot of short time savings and benefits to the single address or residence.
Great review about these motors so that the citizens can make fair decisions about HVAC purchases.
Excellent Instructor very clear and deliberate information.
So true and of the three versions of residential HVAC, single stage, 2 stage and variable stage, the most reliable turns out to be the one that can be only so much efficient.
You would think that if the Government is going to guarantee manufacturers with 14 SEER minimum A/C systems and there are more efficient systems made, that the Government would simply step it up and make the minimum SEER closer to 18. If they did, manufacturers would then be able to produce more efficient systems for less money because of the added volume in sales for 18 or higher systems. As it is, 14 SEER is likely too much on its own in technology which forces the manufacturers to have to charge way more for the others due to limited volume of sales usually affordable to more well off folks. It's truly unfair to mandate systems on the lower efficiency levels when the choices most folks would opt for are the higher SEER had they been more affordable. Sadly, the federal/state minimum SEER ratings are forcing folks to get less value because "the law says" this 14 SEER is all I need but dollar per SEER or dollars per kWh of expensive electricity is what makes systems worth their weight in the end. My guess is, a 14 SEER vs. an 18 SEER likely yields a good 40% less power consumed for the same BTU's. The Government needs to be more proactive in minimum requirements especially when the cost vs benefits tend to be in the 18 SEER range. And those who live in California know that .35 cents per kWh adds up way too fast to be fair to them. All while other States can sell power at 6 cents, 8 cents or 10 cents per kWh and stay happy, Californian's are being forced by the monopoly the state created, CA ISO plus they run the CPUC pretty much to their own benefit vs. the rate payers.
No matter what folks do to be modern and efficient with their homes, it seems to be a losing proposition that one will save money by spending large in home upgrades. No matter what they do to get energy usage lower, the rate increases keep those ideas less attractive. Our home used X amount of power with a years worth of usage 30 years ago. Today, it uses about half what it used yet the cost of power is 4X so the savings didn't occur, it reversed and power bills are way higher even though power consumption is now less. Rate increases with most California electric utilities occur 10 times per year...rate increase notices come with each monthly bill letting people know they are looking for more money for this or that. Most of the reasoning seems to be infrastructure improvements however, most of them have been irresponsible over the past 30 years in keeping in sync with the times, allowing deferred maintenance to enter the budgets year after year, decade after decade. Until now, they are up against a wall due to massive fires and are in panic mode to catch up with a good few decades of needed upgrades.
Increased population and housing projects sure do not help the matter yet, the Government ignores those factors it seems, we are low on water, limited power (man made of course), drought, much Government oversight thus high costs etc. and the cost of living in CA is shameful, regardless of how much folks spend or do to conserve, the state keeps adding (being ignorant) more and more demand on our resources...
Infrastructure spending: importing and housing a newer sleeker voter. I'd wait a little longer to see who wins and if they actually focus on actual infrastructure: utility upgrades, more refineries, development of resources and proven energy technology. But they just about screwed up with water because they bet the farm on the Colorado which is not looking too hot. Or cool.
Don't see what the absurd electricity prices in CA have to do with home upgrade decision making... if you didn't invest in those upgrades you'd now be paying 4x, not 2x... if anything the high prices make the larger upfront investment more worthwhile. I really have no idea what CA has been doing with your money for the past 30 years. Costs should intrinsically be higher just due to fire risk, other weather damage. When fraudsters were running the place in 00' it's hard to imagine they were doing much long term investment. Certainly huge amounts squandered with every new backwards piecemeal policy, from means-testing discounts to subsidizing rich people's solar and back again... But yea no doubt about it you need huge amounts of investment now, wholesale cost is basically irrelevant.
SEER is such a mess. Manufacturers are required to sell only equipment rated at a certain level, want to get everything they can out of the fixed costs for manufacturing the previous rating level, and as you said a lot of people are sold on the minimum rated system that's legal, ergo less demand, functionally making the efficient technology prohibitively expensive. By the time the new tech is deployed at scale and is fairly cheap to manufacture, they need to scrap it all again as it will soon be illegal. The mandates inherently provide little-to-no marginal cost savings, and the savings inherently get worse as efficiency improves in ever smaller jumps. With more workarounds that introduce more points of failure. Almost like the benefit of free markets is their ability to provide differentiation to consumers. All the costs of capitalism, none of the benefits.
@@garrettmillard525Electric rates were not so bad just a few years back, they were in the 18 to 20 cents per kWh range. Today, they are 42 to 48 cent range. People didn't and still don't need new HVAC, the old stuff still works except for the operation cost with high rates...residential bills are $650 to $1,200 monthly for a 2,000 SF house. That will be about the same bill in winter if they require heat pumps. New tech is junk these days by the way, repair costs and frequency of repairs are too often.
@@garrettmillard525BTW becareful when suggesting the market is a free market. The DOE and the EPA cause that free market to be NOT so free and full of mandates.
Im confused my furnace is a constant torque variable speed
Best video i have yet to see on this topic
Ecm motors suck. You can't remove and replace the thermistor on it due to an epoxy from the factory so you pay big for all new.
Good info. Thanks.
Higher repair costs and longer down time to get the part to repair for OEM ECM motors unless you live close to a dense urban area.
Yes the down time for ecm repair isba joke and the repairs cost is crazy. Om an hvac tech and im sticking with my psc
"When it comes to repairs I'm going to pay thousands for technician to install a new motor," I heard you say. I take this to mean a system repair that involves replacing a motor. Would I be wrong in guessing the labor cost is on the order of the materials cost? If yes, then why? We're not repairing the motor. We are replacing it. Sounds like we need a variable speed motor that's not so hard to install however infrequent that might be, because I can't imagine these things have an a high efficiency rating if their lifetime is short.
Power consumption of the constant torque motor decreases when restriction increases.
Power ∝ Torque x RPM.
I just got 8 quotes for a new AC system… 7 of 8 said to get a ECM motor one said PSC…
With a squirrel cage blade an indoor blower motor will actually speed up and draw less current while doing less work.
Have you ever come across the ECM motor that sounds like a jet engine winding up?
From 2007 ECM Goodman Furnace 97 efficient. Was working fine then changed. No ductwork and air flow issues.
When an ECM motor get real loud its usually an air flow issue. Did you check total exertnal static pressure with evaperator clean and dry, blower wheel clean and compare to installation manual for cfm at the measured static. If static is over .9" of static there is definitely an air flow problem. Or it could simply be worn out failing bearing.
@@taylerellis378 Removed blower cage and the wheel spins freely no issues. If you run furnace without filter and jump out service door the noise is the same. Evap is clean. So Could be ECM or motor. Noise only when it switchs to high mode. No problems in the lower speeds.
@@mobilecommunicationsnetwor5268 you are pretty much at the expected service life of the motor 15years so it very well could be simply worn out. But you can check the high voltage going to the motor an make sure its I n an exceptable range and also check the 24vac going to the motor and make sure that is also in range. 120vac plus or minus 10% and 24vac sould be between 23-28vac. Also make sure it is spining the correct direction and there is not anything else causing the noise such as a peice of tape or something stuck in the heat exchanger or evap coil. You may need a pro out there to test the motor outside the cabnet with an ecm motor tester.
@@taylerellis378 I can check both of these things. Could be using the EZ 16 in place of a $900 motor/ECM and a 1 month wait for the part.
ruclips.net/video/dgbTUzaM1dA/видео.html How to video. EZ 16
@@taylerellis378 It has 16 pins and changes speed during operation. Has dip switches cfms choices. It in the factory defaults currently.
Great video
80% of systems with psc? More like 20% here. Seems like constant torque is most common with ecm not too far behind
Tell me about it my torque motor went bad now my blower does not stop running. Told my landlord, his AC guy said he would come back and replace but never did. Ever time i make a fuss about something he rises up my rent. So i have to take it.
Psc motors are reliable, the others are trash, ask any (90%of contractors)the money is gone when u have to buy new ecms, wipes the savings out ,yes ecm more efficient but will not tolerate poor duct work (admitting vast amount of tec wana bees don't know a d thing about duct design) the psc is more forgiving.the lobbiest are the only one that wins , follow the money
8:18 PSC is brushless too
Which motors are brushed?
@@La01781 Universal motors have brushes, like those found in kitchen appliances like blenders, also corded power drills, some washing machines.
@@flat-earther even washing machines? I knew about the drills and stuff. Do vacuums use brushed?
@@La01781 I believe in America washing machines use induction motors and those are without brushes, but in other countries there are many that use universal motors with brushes.
Corded vacuums use universal motors.
Pretty much the higher tech especially with regards to newer HVAC is nothing more than planned obsolescence at its finest, inferior by design, permeated to the core with the robust flavor of our throw-away society at the forefront, making it extremely cost prohibitive to repair vs. complete replacement of entire systems, often with many HVAC outfits tailoring their business model in the sales/installations column, not the service column. The added bonus in all of this will be the fact that the Feds will be having orgasms at the thoughts of how many pieces of equipment with plenty of servicable years left will be euthanized young and prematurely upgraded, all because we all know deep in our hearts that the Federal Government has our best interest at heart, knows us better than we know ourselves, and wants us to have the sexiest SEER rating available. This should make us feel warm all over, like malaria.
You are kidding thousands to replace a variable speed motor that cost like 300 bucks. That's a rip off.
Gee, I thought the 'split' of PSC motors was because there are two windings, a run winding and a start winding. Incoming AC current is split between the two windings in parallel....
It seems like constant torque motors are built for clients that don’t maintain their system. So American.
You keep talking about "when" your heating system gets all clogged up and reduced airflow. Except for keeping a clean filter in the system,,,,,, that has never happened in any of my systems in over 50 years. Why would airflow ever get that bad? This seems to be a false issue.
For the amount of money you save in electric does not come close to the cost of repairing those hi-tech motors. KISS
All of those motors are brushless
$750 to nearly $3,000 to replace a motor??
You are gouging.
Variable speed motor SUCK BALLS. they don't last. the motors are good the electronics in them are cheep Chinese GARBAGE. it cost $800 and up to replace just the motor. the PSC motor cost about $200 to replace but rarely ever needs replaced. the VSM last for about 2 or 3 years.
An ecm adds comfort, ramping, the ability to provide two or more capacities to the system, constant air flow, humidly control and incidentally, energy savings. ROI on the blower motor has never been high on customer's lists. Reduced interior start up and running noise is always appreciated by customers after upgrading to an ecm based system. Many had no idea quiet forced air was possible.
Reliability can be an issue especially when sales techs get to up their commission but don't want to redo bad ductwork.
In a similar manner, Genteq is responsible for some bad engineering of the power electronics especially in the 2.x versions. It is entirely possible for power electronics to protect themselves. You never hear of bad electronics in automobile variable speed applications like compressors, power steering or blowers. You rarely hear of power control failures in minispits with variable speed motors. Genteq has improved their more recent controls and there are now universal retrofit motors that can be field programmed. The future is here; the residential and light commercial industry will adapt.