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Thread: The LED of Motors - Switched Reluctance and the Future of Variable Speed Motos

  1. #1
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    The LED of Motors - Switched Reluctance and the Future of Variable Speed Motos

    I'm an Engineer working with Turntide Technologies. I have used this forum before as a source for education on topics related to energy efficient mechanical and electrical projects. I'm now happy to present a new one that many of you may have never heard of before. I was unaware of this technology before starting at Turntide back in February of 2020. The reality is switched reluctance motors have been around since the 1990s. Historically, they were too expensive and difficult to control for mainstream applications such as in HVAC system so they were relegated to high reliability applications such as nuclear power plants and mining. They are afterall the most reliable motor in the wold requiring virtually no maintenance. With the advancements in computing technology, the cost and complexity of controlling these types of motors has come way down. After nearly 10 years of development and refinement, Turntide Technologies is the only company offering a switched reluctance motor for mainstream HVAC applications. Our first target application is packaged HVAC roof top units (RTUs). Turntide has developed a drop in motor retrofit solution that can significantly improve the durability of RTUs and reduce energy usage by up to 60%. We are currently doing national deployments with fortune 500 companies who have enormous RTU portfolios but with our distribution partnerships, we are now in a position to start promoting this retrofit solution to a broader audience. I thought this would be the perfect form to share. Happy to answer any questions but i'll try and get ahead of a few of them here.

    Turntide motors are a type of Switched Reluctance Motor (SR). They are not induction motors because we do not induce a current on the rotor which means no bearing failures.
    Our phase winding are all isolated from each other and completely encased which means no shorts between phases. We can actually run the motor if a phase is lost.
    We do not vary the frequency like a VFD, we vary the switch speed between phases. The rotors chase the polls of the magnetic field.
    We are not and EC motor. We have no rare earth elements or permanent magnets like and EC motor.
    Our SR motor is fully programmable and speed variable and ranges in size from 1-25 HP.
    It cost as much as an induction motor with VFD
    Qualifies for all variable speed motor rebates
    10 year warranty

  2. #2
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    Quote Originally Posted by Turntide View Post
    I'm an Engineer working with Turntide Technologies. I have used this forum before as a source for education on topics related to energy efficient mechanical and electrical projects. I'm now happy to present a new one that many of you may have never heard of before. I was unaware of this technology before starting at Turntide back in February of 2020. The reality is switched reluctance motors have been around since the 1990s. Historically, they were too expensive and difficult to control for mainstream applications such as in HVAC system so they were relegated to high reliability applications such as nuclear power plants and mining. They are afterall the most reliable motor in the wold requiring virtually no maintenance. With the advancements in computing technology, the cost and complexity of controlling these types of motors has come way down. After nearly 10 years of development and refinement, Turntide Technologies is the only company offering a switched reluctance motor for mainstream HVAC applications. Our first target application is packaged HVAC roof top units (RTUs). Turntide has developed a drop in motor retrofit solution that can significantly improve the durability of RTUs and reduce energy usage by up to 60%. We are currently doing national deployments with fortune 500 companies who have enormous RTU portfolios but with our distribution partnerships, we are now in a position to start promoting this retrofit solution to a broader audience. I thought this would be the perfect form to share. Happy to answer any questions but i'll try and get ahead of a few of them here.

    Turntide motors are a type of Switched Reluctance Motor (SR). They are not induction motors because we do not induce a current on the rotor which means no bearing failures.
    Our phase winding are all isolated from each other and completely encased which means no shorts between phases. We can actually run the motor if a phase is lost.
    We do not vary the frequency like a VFD, we vary the switch speed between phases. The rotors chase the polls of the magnetic field.
    We are not and EC motor. We have no rare earth elements or permanent magnets like and EC motor.
    Our SR motor is fully programmable and speed variable and ranges in size from 1-25 HP.
    It cost as much as an induction motor with VFD
    Qualifies for all variable speed motor rebates
    10 year warranty
    Interesting. Thanks for sharing. Do you have any links to any Youtube video or something else that explains these motors a little better? Just what you listed as "answers to my questions" has left me with a few questions....

    "Turntide motors are a type of Switched Reluctance Motor (SR). They are not induction motors because we do not induce a current on the rotor which means no bearing failures."... I'm not an expert on anything, but I've never heard that "induced current" was a common cause of failure for motor bearings. I'm pretty sure bearings can and do fail for many other causes, and I'm pretty sure they still can and will fail in your motors. Please correct me if I'm wrong.

    "We do not vary the frequency like a VFD, we vary the switch speed between phases"... What does this mean? In my mind, switching the speed between phases is pretty much the same thing as varying the frequency. What's the difference?

    Where is Turntide Technologies located? Is your company working with other motor manufacturers, or are you trying to be the only company available with this type of technology?
    If at First You Don't Succeed, Skydiving Is Not for You.

  3. #3
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    So, if you do not have magnets in the rotor, how do you get the "chasing" effect without inducing a current in the rotor? What magic is this?
    A dying culture invariably exhibits personal rudeness. Bad manners. Lack of consideration for others in minor matters. A loss of politeness, of gentle manners, is more significant than is a riot.
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  4. #4
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    You can enter our URL turntide dot com. We have lots of videos and collateral on the site that goes into greater detail.

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    We are creating a magnetic field by energizing wound copper opposing bobbins. There are thee pairs of bobbins, each representing a phase. The rotor which is made of solid ferrus metal tries to align with the poles created by the magnetic field. Just as the rotor spokes align with the polls, we turn off the energy to that pair of bobbins and switch it to the next pair and so on and so on. This makes the rotor spin. We turn on and off the bobbins 20,000 per second. Check our website, the video explains it better than I can.

  6. #6
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    You know, a few years ago LED light bulbs were touted as being one of the greatest inventions ever. They were 4 times as expensive as normal light bulbs, but they were said to be able to easily pay for them selves with the energy savings and the fact that they would last basically forever. I've now got almost all of the bulbs in my house switched over to LED.

    So far for me, they have not lived up to the hype. I have some that have already quit working. I don't know if ANY of them will come close to the 10 years or whatever the projected life span was supposed to be. I believe most of these light bulbs even came with a 10 year warranty (kind of like these fancy motors are supposed to have). Since I don't like having to deal with warranties though, I just sucked up the loss and bought replacements.

    Same thing with LED Christmas lights. I bought several strings of them with the hopes that they would work forever too. So far I've only experienced disappointment.

    I have no doubt that that if I were the purchasing agent for the "nuclear power plants and mining" industry and didn't mind paying an exorbitant amount of money, I could obtain some that would last for as long as they are supposed to be last. As a general consumer though, sadly I don't think I have this option.

    Why should I believe that once you figure out a way to make them cheap enough for general use, that these motors won't suffer the same types of reliability issues? Are these things really going to be the answer to everyone's prayers like you say they will?
    If at First You Don't Succeed, Skydiving Is Not for You.

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  8. #7
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    So I went to the website... watched the well made video...

    Can you explain the difference between this motor and an ECM motor running on a VFD???

    Seems very similar to me... almost the same.
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

  9. #8
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    Quote Originally Posted by ga-hvac-tech View Post
    So I went to the website... watched the well made video...

    Can you explain the difference between this motor and an ECM motor running on a VFD???

    Seems very similar to me... almost the same.
    They are not the same. EC motors use permanent magnets and rare earth elements in the rotor and they do not switch between phases. These expensive materials make it impractical for larger size motors which is why EC motors are almost always fractional HP. Not to mention the high environmental toll mining rare earth elements takes. Turntides SR motor does not go into fractional HP sizes so we do not compete with EC motors. Our rotors are made from ferrous solid metal, so no magnets or rare earths. We have motors from 1-25 HP now. There is no laws of physics that prevent us from making this motor in much larger sizes.

  10. #9
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    Sounds to me like a very similar design... with a few differences (based on HP size of the motor)...
    And packaged with a LOT of hype.

    Lets see how they perform...
    And lets see what a 1 HP TT motor, next to a 1 HP ECM (variable speed) motor perform...
    Side/side comparisons are, after all, where the rubber meets the road!

    Can you provide a video of the above comparison???
    Say a Genteq vs Turntide motor???
    With a load on the motor, and amp/clamps to see how much power they are using???
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

  11. #10
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    Quote Originally Posted by ammoniadog View Post
    You know, a few years ago LED light bulbs were touted as being one of the greatest inventions ever. They were 4 times as expensive as normal light bulbs, but they were said to be able to easily pay for them selves with the energy savings and the fact that they would last basically forever. I've now got almost all of the bulbs in my house switched over to LED.

    So far for me, they have not lived up to the hype. I have some that have already quit working. I don't know if ANY of them will come close to the 10 years or whatever the projected life span was supposed to be. I believe most of these light bulbs even came with a 10 year warranty (kind of like these fancy motors are supposed to have). Since I don't like having to deal with warranties though, I just sucked up the loss and bought replacements.

    Same thing with LED Christmas lights. I bought several strings of them with the hopes that they would work forever too. So far I've only experienced disappointment.

    I have no doubt that that if I were the purchasing agent for the "nuclear power plants and mining" industry and didn't mind paying an exorbitant amount of money, I could obtain some that would last for as long as they are supposed to be last. As a general consumer though, sadly I don't think I have this option.

    Why should I believe that once you figure out a way to make them cheap enough for general use, that these motors won't suffer the same types of reliability issues? Are these things really going to be the answer to everyone's prayers like you say they will?
    We already have made them "cheap enough for general use". Our motor costs about the same as an inverter rated induction motor with VFD so its not four times as expensive as in the LED comparison. The were cost prohibitive before because of the cost and complexity of controlling them but those technical challenges have been overcome. If you have any experience with induction motors and VFDs you know that motors are very prone to failure because of the issues caused by shaft currents and bearing failures as a result of forcing down the frequency. Induction motors were not designed to be slowed down so although you can do and get savings out of the fan laws, you are slowly killing the motor and decreasing efficiency. The switched reluctance approach eliminates these issues. Its not a silver bullet and there will always be challenges when harnessing the powers of the universe but its a better alternative to induction motors and VDS which is only now available for HVAC applications.

  12. #11
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    Quote Originally Posted by ga-hvac-tech View Post
    Sounds to me like a very similar design... with a few differences (based on HP size of the motor)...
    And packaged with a LOT of hype.

    Lets see how they perform...
    And lets see what a 1 HP TT motor, next to a 1 HP ECM (variable speed) motor perform...
    Side/side comparisons are, after all, where the rubber meets the road!

    Can you provide a video of the above comparison???
    Say a Genteq vs Turntide motor???
    With a load on the motor, and amp/clamps to see how much power they are using???
    If we set that up, the energy usage and torque profile would be about the same. Wish I had a video but I don't. Its a long read but if you are interested, there is a good comparison chart between Turntide and EC Motors in our Learning Center. Again, we are not trying to compete with EC motors right now. We are going 1 HP and above. EC motors cannot compete with us on price when you get into these sizes. They would simply be too expensive.

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  14. #12
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    Quote Originally Posted by Turntide View Post
    If we set that up, the energy usage and torque profile would be about the same. Wish I had a video but I don't. Its a long read but if you are interested, there is a good comparison chart between Turntide and EC Motors in our Learning Center. Again, we are not trying to compete with EC motors right now. We are going 1 HP and above. EC motors cannot compete with us on price when you get into these sizes. They would simply be too expensive.
    Thank you...

    This is kinda what I expected... and it is fine!

    As you say... ECM motors are a good fit for fractional HP motors...
    Your motors are a good fit for 1 HP+ motors...

    Sounds like the industry has a new player...
    Lets see how it works out... with the (magic) test of time!

    THX for your input...
    When I have time... will find that (long) article and read it.
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *The value of comfort, over the long term; leave economic choices behind!
    Choose your contractor wisely!

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