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  1. #61
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    Quote Originally Posted by markz528 View Post
    I don't know why I try to help with these types of issues on this board. I tried some years ago and got the same type of attitude.

    All I have to say is that I make a darn good living solving motor, VFD application and VFD installation issues all over the world. I don't know everything, but I have very strong contacts at most of the large Automation vendors that have taught me well and give me guidance when needed.

    This response is quite unfortunate.

    There is no reason the VFD would not work in this application properly set up.
    Mark, don't stop posting because of the ignorance of others on the internet - it is guaranteed that you will find a broad range of opinions that are not based on fact or real life experience. Like you, I make my living at deploying VFD / ACVector / ACServo drive technology. At last count, my company has over 5000 drives applied since 1995 most of which are in motion applications with nearly 100% of them operable at full torque at zero speed while holding precise position up to 300HP.

    I am fond of Martin Luther quotes and this thread has reminded me of two of my favorites:

    "Are you ignorant of what it means to be ignorant?"
    and my all time favorite . . .

    "Perhaps you want me to die of unrelieved boredom while you keep on talking"
    . . . or in the case of this forum "keep on typing"

    Last edited by motion guru; 03-07-2018 at 12:49 PM.

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    I too was curious as to the ability to run VFD's and motors down to zero speed and have full torque. People here like Motion told me it wasn't just possible, but standard practice on many things. I ended up with a 3hp Black Max inverter motor, Invertek VFD with encoder feedback and the piece of equipment performs beautifully down to zero speed.

    The number of people I talked to though in sourcing equipment for this project who told me that AC motors didn't work like that was astoundingly high. I needed the ability to start and move partial revolutions at almost zero speed, multiple people told me that doesn't work. Sure does though.

    I don't know if I needed the encoder feedback or if the drive could have done it without, but I threw it in and the equipment is in service so it'll never get messed with. Next unit will have the encoder as well since its been proved it just works.

    So you folks with the knowledge, please keep posting, it's appreciated.

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    Quote Originally Posted by motion guru View Post
    Mark, don't stop posting because of the ignorance of others on the internet - it is guaranteed that you will find a broad range of opinions that are not based on fact or real life experience. Like you, I make my living at deploying VFD / ACVector / ACServo drive technology. At last count, my company has over 5000 drives applied since 1995 most of which are in motion applications with nearly 100% of them operable at full torque at zero speed while holding precise position up to 300HP.

    I am fond of Martin Luther quotes and this board has reminded me of two of my favorites:

    "Are you ignorant of what it means to be ignorant?"

    and my all time favorite . . .

    "Perhaps you want me to die of unrelieved boredom while you keep on talking" . . . or in the case of this forum "keep on typing"

    Quote Originally Posted by rbent View Post
    I too was curious as to the ability to run VFD's and motors down to zero speed and have full torque. People here like Motion told me it wasn't just possible, but standard practice on many things. I ended up with a 3hp Black Max inverter motor, Invertek VFD with encoder feedback and the piece of equipment performs beautifully down to zero speed.

    The number of people I talked to though in sourcing equipment for this project who told me that AC motors didn't work like that was astoundingly high. I needed the ability to start and move partial revolutions at almost zero speed, multiple people told me that doesn't work. Sure does though.

    I don't know if I needed the encoder feedback or if the drive could have done it without, but I threw it in and the equipment is in service so it'll never get messed with. Next unit will have the encoder as well since its been proved it just works.

    So you folks with the knowledge, please keep posting, it's appreciated.
    Cut them some slack...this relatively new technology.

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  6. #64
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    Quote Originally Posted by Miguels244 View Post
    Cut them some slack...this relatively new technology.
    Relatively new? It’s 2018 . . .

    The first commercially available cheap vector drives hit the market 25 years ago. The bookshelf Control-Techniques Vector drive with encoder feedback . . . we installed dozens of them in positioning applications in 1993 easily managing full torque positioning at zero speed. I remember programming a quartz clock movement and putting a second hand the end of a 100 hp motor shaft to show positioning and timing accuracy.

    I designed a feedback kit that put a 4096 count quadrature encoder on the non-drive end of Reliance XT TEFC motor using an insulating mounting block and coupling.

    Luther’s quotes are all the more applicable.

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    Quote Originally Posted by motion guru View Post
    Relatively new? It’s 2018 . . .

    The first commercially available cheap vector drives hit the market 25 years ago. The bookshelf Control-Techniques Vector drive with encoder feedback . . . we installed dozens of them in positioning applications in 1993 easily managing full torque positioning at zero speed. I remember programming a quartz clock movement and putting a second hand the end of a 100 hp motor shaft to show positioning and timing accuracy.

    I designed a feedback kit that put a 4096 count quadrature encoder on the non-drive end of Reliance XT TEFC motor using an insulating mounting block and coupling.

    Luther’s quotes are all the more applicable.
    I think Miguels comment was ironic stab to thermite's "deecee drive" babbling(or linguistic experiment) direction.

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    Quote Originally Posted by rbent View Post

    I don't know if I needed the encoder feedback or if the drive could have done it without, but I threw it in and the equipment is in service so it'll never get messed with. Next unit will have the encoder as well since its been proved it just works.
    Better have the encoder if you need to go really slow or need to hold position at zero speed.
    ACS800 works down to 0.5hz on sensorless control, Yaskawa claims to work down to 0.25hz on some late models.

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    Quote Originally Posted by motion guru View Post
    Relatively new? It’s 2018 . . .

    The first commercially available cheap vector drives hit the market 25 years ago. The bookshelf Control-Techniques Vector drive with encoder feedback . . . we installed dozens of them in positioning applications in 1993 easily managing full torque positioning at zero speed. I remember programming a quartz clock movement and putting a second hand the end of a 100 hp motor shaft to show positioning and timing accuracy.

    I designed a feedback kit that put a 4096 count quadrature encoder on the non-drive end of Reliance XT TEFC motor using an insulating mounting block and coupling.

    Luther’s quotes are all the more applicable.
    Quote Originally Posted by MattiJ View Post
    I think Miguels comment was ironic stab to thermite's "deecee drive" babbling(or linguistic experiment) direction.
    Sorry, I missed the winky emoticon.

    Part of what has really changed is the computing power and speed of modern VFDs...and the insulation quality and design of asynch motors.

    Remember when ATS came out with the auto tune servos?
    Hell it hasn't been that long since analog servo amps were the norm.

    Or maybe I'm just old.

    I have to wonder how much longer synch motors will be really needed.

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    Lots of applications yet for PM motors . . .

    years ago I made a spreadsheet of literally hundreds of motors that rated them in terms of torque / amp and torque / inertia - this made it easy to select the optimum motor whether servo or induction motor, 2-pole, 4-pole, 6-pole or higher yet . . . we have applied motors with up to 276 poles.

    Also, there are applications where the back EMF of the PM motor is helpful for braking if the drive faults out and you don't want to drop / crash the load . . . just short the motor leads across a resistor bank and bring the load to a stop.

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    Quote Originally Posted by motion guru View Post
    Lots of applications yet for PM motors . . .
    Aye. If the "Must use Windows", "Linux RULES", "VFD is the ONLY answer" crowd -same small-minded mental class of zealots, exactly.. had but to give-up ALL their cordless AND corded series/universal-wound DC/AC motors in handheld powertools?

    THEN.. their voice would be heard loudly enough!

    Until then? And they "make it work"..... 100% with AC motors instead?

    There IS NO "one solution fits all needs".

    Why would we ever expect there to be?

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    Quote Originally Posted by thermite View Post
    Aye. If the "Must use Windows", "Linux RULES", "VFD is the ONLY answer" crowd -same small-minded mental class of zealots, exactly.. had but to give-up ALL their cordless AND corded series/universal-wound DC/AC motors in handheld powertools?

    THEN.. their voice would be heard loudly enough!

    Until then? And they "make it work"..... 100% with AC motors instead?

    There IS NO "one solution fits all needs".

    Why would we ever expect there to be?
    Ac motors have pretty much made the brush dc permanent magnet motors obsolete also on cordless tools. Probably good 90% of professional cordless tools sold nowadays are synchronous ac motors and 200 usd cordless drill contains pretty fancy sensorless "vfd".(motor is permanent magnet synchronous type tough)

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    Quote Originally Posted by MattiJ View Post
    Ac motors have pretty much made the brush dc permanent magnet motors obsolete also on cordless tools. Probably good 90% of professional cordless tools sold nowadays are synchronous ac motors and 200 usd cordless drill contains pretty fancy sensorless "vfd".(motor is permanent magnet synchronous type tough)
    I hear that. But can you explain where TF all those damned BLUE-WHITE SPARKS are coming from?

    I mean .. my "heavy" machine tools are b****y ancient, and mostly 3-Phase (RPC +2 Phase-Perfects, DC Drives for the 10EE's, no need of VFD on the mill, shaper, or Cazeneuve - all have Reeves or Klopp vari drives).

    But my hand power tools and sawdust-makers are modern, some bought within the past calendar quarter, both corded and cordless.

    Brush sparks are the rule, not the exception.

    As I am NOT "religious" as to AC or DC, only "fit for the purpose", I'd be delighted if there were NOT arc'ey-spark'ey brushes to potentially ignite vapours or wood dust.

    Common portable "Shop vac", and not the long-since saner professional dust-collector or fume hood at the head of my "wish for" list. The rest has a while to go before worn out / able to justify replacement. A rather looong while, if past experience is any guide.

    I don't see that happening in the US consumer market just yet.

    What brands and models have I missed?


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    Quote Originally Posted by thermite View Post
    I hear that. But can you explain where TF all those damned BLUE-WHITE SPARKS are coming from?

    I don't see that happening in the US consumer market just yet.

    What brands and models have I missed?

    Practically any brand of cordless tools in bit more serious category. And make that 200 dollar tool --> 95 dollar tool
    Makita 18-Volt LXT Lithium-Ion 1/2 in. Brushless Cordless Hammer Driver-Drill (Tool Only)-XPH12Z - The Home Depot

    Search Results for brushless at The Home Depot

    No break trough on corded tools yet, only very few and rare ones.

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    Might as well muddy the waters a bit more.
    The axial brushed D.C. motors by Kollmorgan, PMI, and others provide a specific solution.
    Extremely fast, electrically and mechanically.

    Servo Disc Brush DC Motors | Kollmorgen | Brush DC Electric Motors
    Brushed Pancake Motors

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    Quote Originally Posted by MattiJ View Post
    Practically any brand of cordless tools in bit more serious category. And make that 200 dollar tool --> 95 dollar tool
    Makita 18-Volt LXT Lithium-Ion 1/2 in. Brushless Cordless Hammer Driver-Drill (Tool Only)-XPH12Z - The Home Depot

    Search Results for brushless at The Home Depot

    No break trough on corded tools yet, only very few and rare ones.
    "Brushless" still implies DC, though. Not at all "new" either.

    Didn't start off as inexpensive, nor as rugged as conventional commutator and brushes were. Should be about due for both, though. Most especially if more design-wins are in high unit-volume devices.

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    Quote Originally Posted by thermite View Post
    "Brushless" still implies DC, though. Not at all "new" either.

    Didn't start off as inexpensive, nor as rugged as conventional commutator and brushes were. Should be about due for both, though. Most especially if more design-wins are in high unit-volume devices.
    Well the brushless cordless tool motors are running on 3-phase full bridge PWM modulated AC, implied or not.
    (motor controller or the VFD part is of course fed with DC)
    Or you can call VFD + induction motor a brushless dc motor since the VFD filtering caps operate on DC

    BLDC = Brushless DC = Synchronous permanent magnet motor, usually? optimized for 3-phase trapezoidal waveform instead of sinusoidal waveform.

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    Quote Originally Posted by MattiJ View Post
    Well the brushless cordless tool motors are running on 3-phase full bridge PWM modulated AC, implied or not.
    (motor controller or the VFD part is of course fed with DC)
    Or you can call VFD + induction motor a brushless dc motor since the VFD filtering caps operate on DC
    YOU may. I would not.

    It doesn't make much sense to go that route when an ignorant - and CHEAPER DC motor is happy enough off DC batteries for cordless, or an ignorant SCR for corded.

    At least the description of a Tomcat as a "ball-bearing mouse trap" takes a more legitimate route to abuse of the language.

    This Dog won't hunt.

    Got a better example of a VFD + 3-Phase AC-not-DC motor hand power tool?


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    Quote Originally Posted by thermite View Post
    YOU may. I would not.

    It doesn't make much sense to go that route when an ignorant - and CHEAPER DC motor is happy enough off DC batteries for cordless, or an ignorant SCR for corded.

    At least the description of a Tomcat as a "ball-bearing mouse trap" takes a more legitimate route to abuse of the language.

    This Dog won't hunt.

    Got a better example of a VFD + 3-Phase AC-not-DC motor hand power tool?

    Everything from PC fans to bat mothers in hand tools has ditched brushes.
    The only p,ace left is in specialty service.

    Give me a single example of a three phase hand tool.

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    Quote Originally Posted by thermite View Post
    It doesn't make much sense to go that route when an ignorant - and CHEAPER DC motor is happy enough off DC batteries for cordless, or an ignorant SCR for corded.

    Got a better example of a VFD + 3-Phase AC-not-DC motor hand power tool?

    About half the size of brushed motor, no brushes to wear, mechanically simple to manufacture.
    Downside is that you need hall effect sensors for rotor position measurement, rather fast CPU to handle the PWM sequencing and 3-phase 6 transistor full bridge to make it turn from dc source. Or sensorless vector control that makes basic VFD look simple.

    BOLTR: BEST IN CLASS? Makita Brushless Drill - YouTube (Black box is the "VFD" part containing 3-phase full bridge)
    Better Know a BLDC: Sensorless Brushless DC Motor Control
    Brushless' 'DC' 'motor' 'control' 'and' 'drives - Infineon Technologies
    BLDC Motor Control Algorithms | Renesas Electronics India

    Radio controlled planes have switched to BLDC motors 15 years ago, on hand tools it has became really popular in last 3 years or so.

    (links wont work because forum software is throwing database error with more than 3 links and parsing)

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    Quote Originally Posted by MattiJ View Post
    About half the size of brushed motor, no brushes to wear, mechanically simple to manufacture.
    Downside is that you need hall effect sensors for rotor position measurement, rather fast CPU to handle the PWM sequencing and 3-phase 6 transistor full bridge to make it turn from dc source. Or sensorless vector control that makes basic VFD look simple.

    BOLTR: BEST IN CLASS? Makita Brushless Drill - YouTube (Black box is the "VFD" part containing 3-phase full bridge)
    Better Know a BLDC: Sensorless Brushless DC Motor Control
    Brushless' 'DC' 'motor' 'control' 'and' 'drives - Infineon Technologies
    BLDC Motor Control Algorithms | Renesas Electronics India

    Radio controlled planes have switched to BLDC motors 15 years ago, on hand tools it has became really popular in last 3 years or so.

    (links wont work because forum software is throwing database error with more than 3 links and parsing)
    DeeCee not AC in those examples, and all the way. Still zero evidence of polyphase AC + VFD.

    Lot of time spent proving what I've been saying all along.

    DC is best for some things. AC is best for others. They have an overlap. Extending that overlap to the fringes is costly - for either one.

    No need to be bothered.

    Just use what is the better economical choice, so long as fit for the purpose.

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    So you think that the bldc motor without electronics is going to run if you connect it directly to dc power supply?

    Or is the bldc motor going to run if you connect it to 3-phase vfd?


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