I have been studying this sort of thing for a few years, and I have watched other engineering and machining channels. I learned more in 5 minutes of your channel than ALL of the other channels in YEARS! You are a gifted teacher, thank you Jeremy.
Amen, Amen and AMEN! This man KNOWS how to turn a high tech subject to a "piece of cake". Any technical school would be a fool not to hire this man YESTERDAY. He is a treasure for sure. May Jesus continue to gift him with knowledge that can be taught easily to the masses.
Thanks, man! Sometimes you find EXACTLY what you were searching for on UA-cam and for me, this is one of those moments. Your video saved me a LOT of time, headache and money. Keep up the great work 👍
You explain the process that you went through to get the results that you did. That's why your videos are so good for the common person. You don't just tell us what to do, you show how you reached each point of the process. Thanks Jeremy and keep up the good work.
It's important to note that when you slow the motor down you also lose power. The torque on the rotor is determined by the strength of the magnetic field acting on it, which pretty much stays constant, leading to a loss of power (same torque at slower speed=less power). This is a problem for machine tools since you want constant power throughout the speed range (for example a drill press, lathe, milling machine etc.), meaning torque needs to increase (NOT stay constant!) as speed decreases to keep the available power more or less the same. Work done by a particular cutting tool moving past the material at X speed and at Y depth of cut is the same regardless of radius of action (small drill vs large, small milling cutter vs large, small diameter work piece in lathe vs a large one etc), therefore if the RPM is dropping (to keep the tangential speed constant), torque needs to increase for a constant force behind the cutting edge. Power is Force X distance/time, so constant force at the tool requires more torque as the radius of action increases (and constant tangential speed require less RPM as radius increases). The only real solution is a mechanical reduction, i.e gears and pulleys, which multiplies torque proportionally as the speed decreases, keeping the power constant (more or less, ignoring some mechanical losses). Or, sufficiently oversize the motor that you still have enough power at the slowest speed you will be running it, but that's obviously not as efficient, and not nice to the motor. There is NO magic solution, embrace mechanical reduction whenever you have it, even when you have a 3-phase motor with a VFD, so you can keep the motor running as close to its rated speed as possible, for maximum available power and a cool running motor (the motor fan also slows=less air flow!). I would love to build an external reduction gearbox/pulley system for my future lathe, to achieve very slow speeds at full power and have more speeds in between the stock speeds (be it a geared head lathe or a belt drive). I'm not a fan of slowing motors down at all, although a VFD with a big 3 phase motor would be nice for soft starts, quick stops, and moderate speed control between the different gear/pulley speeds.
Within seconds I realised you are a smart cookie who actually knows what you're talking about. That's rare on UA-cam. I didn't need to see another video, insta-subscribed!
My camera finally quit. Time to buy a new one! I will finish the "Question and Answer video" as soon as I can! I would love to know what kind of camera you all would recommend.
I’m sitting here trying to figure how the speed control on a fan motor works and I’ve been racking my brain on it a triac style speed control would work!!! I’m so glad to have found your channel!
Well they don’t use brushless induction motors. They use brushless dc motors (which uses pwm to control speed) and brushed dc motors (which uses voltage to control speed). Those are much easier and very compact speed controllers to manufacture
gifted teacher ..keep em coming ...everyone loves your flavor on these subjects ....what ever it is you have it .... thanks M from down under Australia 240v
Although you indeed can't dim an induction motor it does sound like it's not even starving the motor because the triac isn't turning off. Because the lacking of current with an inductive load it's hard to turn off a triac. So I think if you place a bulb parallel to the motor while using the dimmer it will not dim either because the triac isn't turning off :D
You have the best basic motor education videos I have seen. This video is about the most ask question ever and few explanations about this subject on youtube. And for whatever reason, there are few basic motor education videos in a real setting using real stuff that you would really find for cheap or free. This is a great video series you have about motors. Thanks.
You are a very talented individual and teacher. I was able to follow and understand your message. I have subscribed and will visit this site often. Thank you for providing such good content.
You have done the absolute best job at explaining this exact topic that I've found yet... and I've been scouring the internets for a long while. Very good video, AWESOME demonstration! Thank you very much for this.
Thank you for letting me know. I actually made the video because so many viewers have asked about it, but when searching UA-cam and the internet, there was conflicting information and some things that were just wrong. This video has a part two as well if you are interested. ua-cam.com/video/JTlHNOaBnPI/v-deo.html
Oh I'm already subscribed and watching all your videos! You're awesome and so are your videos! (On a side note I actually found your video because I'm making a workshop of my own... I've been wondering if it was possible to change the rpm of my bench grinder... I'm still not 100 percent sure what the answer is, but I think it's a "no" or a "not worth it", after watching your videos I understand electric motors a whole lot more and now have a good introduction enough to be able understand more of the information out there on the internet in regards to these topics.) Thanks again! ... I'm pretty sure the answer is I can't because a VFD for single phase motors is rare and works only for very particular induction motors, and my motor is not one of those because it most likely has a start winding with a capacitor.... I stop understanding after that point... but I'll just go review your videos again.
Thank you for your excellent presentations. I have a 30 year old Thermador vr600 kitchen exhaust fan with a single phase 120 volt induction motor. It seized up and was able to repair it by lubricating the mounting bushings, no bearings. There was no capacitor and the motor turns on with a 360 degree rotary switch that graduates from high to continuously lower speeds without electronic speed control. Variable speed and no capacitor, how is this possible.
Thank you. Someone designed my furnace with a three speed winding motor for variable speed and added a triac lamp dimmer in the controller to ensure failure. Luckily it was the triac that shorted with no motor damage.
I'm an electrical engineer with 20+ years experience and I feel you produce excellent content. On another video you had mentioned speed control and I commented that a TRIAC PWM circuit will control the speed of an AC induction motor. I have designed the circuitry, tested it, and verified that it does change the speed of a fan, but that is a motor under load, unlike the motor in your test. I think that it is accurate, however, to say that in an applied, practical sense a TRIAC PWM circuit will control the speed of an AC induction motor because I've never had the need to control a motor that wasn't under a load. It's similar to testing amplifiers and seeing a high gain in testing that doesn't translate once the amplifier is driving an actual load that requires some impedance matching.
Jeremy Fielding These were huge industrial fans that used large AC induction motors with starting capacitors and belt-pulley mechanical translation between the motor and the fan axle. In fact, they were so large that we activated them with 5 - 6 inch wide contact switches that were themselves activated by relays and optical switches (to isolate industrial noise from logical circuits). We weren’t using a light dimmer switch. This circuit used a MAC224 40A TRIAC, so it wasn’t designed for indoor oscillating fan motors.
Great video... I found this when searching how to control a vibration motor for soil separation. Many videos have said buy this motor and a variable fan speed controller and it would work. But almost anyone that tried it made a comment under the video that it was either off or full speed... the controller didn't work. I believe your explanation just proved why. Sad, because I really believe I will need that variable control. Any direction you could point me would be appreciated. Thanks Again!
Thank you Jeremy so much for explaining this I've been trying to figure this out because I am building a metal lathe and I want to be able to control the speed without using a belt system or gears.
Thanks for the awesome explanation. I wondered why I couldn’t vary the speed of a motor I have, and. Now I understand. Glad we have intelligent people like you on here .❤️🤠
Thank you Jeremy for the clear information on how to reduced speed of motors. I have been having to sort out this issue for a month and now I know what can work and what won't.
I love this guy. Why can't they explain stuff this way in school? A lot more people would be interested in electricity and electronics. The way it's presented in school makes it seem like you have to be a genius or math wizard to understand technology. It turns out you just need a good teacher and some stuff to experiment with.
I am currently experiencing some issues with a pentek intellidrive VFD which can be used with 2 or 3 wire single phase 240v submersible pump motors. Specifically I am seeing voltages from the VFD which I can not wrap my head around. An engineer suggested that perhaps it is due to the PWM and possible lack of a low pass filter on my meter. Anyway it's a shame that this video isn't able to discuss the nuts and bolts of the single phase VFD just yet, however I am grateful for all the great information here and the clarity your videos have brought me on the the different characteristics of the various motor types. Thank you very much for your great videos.
I think you require a "true rms" multi meter. Normal meters are only designed to work at 50 or 60 hz, any freq outside this range such as what a VFD would output will result in incorrect readings
I get it, yaaaa! So if you change the number of peaks and valleys, or frequency, from 60 to 50 it goes slower. it's chasing fewer of these so it slows down. Great teacher, thanks Jeremy!
Thank you, have made a tumbler out of an old gas dryer. Ideally we wanted the drum to turn slower. Presently at about 50 RPM. You just saved us a whole lot of head scratching - the plan was to try a dimmer switch. ....Life is still good though. Thanks for the video!
So basically for all common cheapo single phase induction motors, stay safe and use a system of pulleys or gears? Fancy speed control stuff for 3 phase motors, go VFD. Good video and explanation! Maybe I can start thinking about building a metal cutting band saw or belt sander.
I can’t believe that I actually understood what this man just explained. You know that old stupid saying’ those who can, do. Those who can’t, teach. Well Jeremy, you just sent that old worthless piece to its eternal grave as far as I’m concerned… thank you! Ps: VFD’s are the only way to compensate for a variety of ‘load’ changes in a variety of systems. Well done.
"A vfd is the only proper way to vary the speed of an induction motor." Thanks a lot for that bro! \m/ All the other way that are there on the internet are probably for views or theoretical "flaunting" i guess, because neither do they work without damaging the system nor are they used anywhere especially for professional and commercial purposes.. great job
Someone installed fan speed controller (looks like a light dimmer) at church. I asked him how much he paid for it, he said about 50 dollars. Seems like they make a speed controller for an induction motor. I am curious what is inside them. Excellent video btw, I didn't know that reducing the voltage doesn't affect the speed of an induction motor (under no load conditions).
I hope you still read comments on 4 year old videos, Jeremy. I’m wondering if you could make a DIY VFD for single phase motors (and teach us all how to do it)? There’s probably a reason that they’re impossible to find but I have great faith in your ability to pull this off! ; ) Who knows, there could be a business opportunity for you in this! (I.e. having these VFDs manufactured (overseas somewhere) to your design specs.)
I'm in the fitness equipment industry and I've been trying to find a way to test the 3 phase AC drive motors in treadmills...I guess I need a VFD with a potentiometer! You should do a video on that set up you have there!
Great video. Just a quick note. Make sure that the motor that you're using with a vfd is "inverter duty". VFDs create high voltage spikes and insulation can fail faster (less motor life) if it's not designed for the higher voltage.
I’ve been working on a single phase drive (motor driver) for a long time. I haven’t had enough time to devote to it. But, I’ll get serious and will let you know when I have it. There probably isn’t a way to do a “one size fits all”, but there is a way for those who are qualified to build something which could become dangerous for those who don’t have the background in higher power devices to play with them. The power coming from AC/mains outlets is beyond a kilowatt! Sometimes two or more Kw.
That was interesting. We built a label roller out of an old B&D drill running off a dimmer switch to control the speed. It worked, but you had to start fast, then dial it back to the desired speed. Since the printer only went so fast, we used a rubber mini drum sander piece to fit in the core, to let it slip if it got going to fast for the printer on start up. I didn't want to pull the labels through the printer before they had a chance to print. Mind you, we used a Dymo printer for 4x6 shipping labels, printing all 250 labels in one step. Each new label, would pull the roll back to the registration mark, then print the next. It worked flawlessly, so long as you had the drill running in the right direction. Since we started winding them on an old label core, controlling the speed of the motor was necessary, as the more the roll gathered, the slower the drill needed to run. I think we printed around 40,000 labels using this method.
Your a wise electrical engineer,,, I'm working on my friends yath has heatpump,,it's a 89 boat,,had potentiometer slide control for fan speed,,they changed system a few years ago,,,my concern is the old thermostat is going to burn out induction motors,,,one was gone when he bought the boat,,and I noticed a loud hum
They do make a single phase freq drive for air conditioner condenser fan motors. They are used in conjunction with a thermistor to control head pressure. If you could get ahold of one, you could replace the thermistor with a potentiometer. However as I understand it you must only use a single phase freq drive on a motor with ball bearings because it will elongate sleeve bearings.
Thanks for making this video. I have a much better understanding of just how a electric motor works. Again, thanks for taking the time to make this video. :-)
Fabulous Information You have an excellent speaking style, and I appreciated your demonstrations, and found your explanations to be clear and understandable. Well Done! Definitely subscribing.
you can get single phase VFD's especially at low power levels. it is also possable to modify certain single phase motors to accept a 3 phase input but it will result in an unbalenced load of the need for external componants.
Great video! I am having some trouble slowing down a 12amp brushed Harbor Freight Pipe Threader. I am using the threader as a power source for a sheet metal bead roller. It works good, but a little too fast. I purchaser a Router Speed control like you show in your video. The threader does not have variable speed in the switch and is a brush type 110v AC motor. The threader is 12amp but I assume that is under load, but I could be wrong on how that works. I get absolutely no effect using the Router Speed Control. I did plug my 4 grinder in and it kind of made in run slower but choppy. Thanks
Your techical explanation was great. I was just about to try this myself. I understand that many 3 phase vfd will run split phase or single phase induction motors as long as there is no start switch or start capacitor.
oops. Thie first link I found was this discussion. www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/single-phase-motors-may-run-off-vfds-177077/. I will try to locate the vfd products I was looking at a while back.
Oh I watched that one a while back I should go back and watch it. Thank you #Jeremy your videos have inspired me to dream big and be resourceful. It's a whole new world I haven't discovered yet.
Your channel came up on my recommended videos, looks interesting and informative, just watched the one on varying induction motor speeds, something I'd not really thought about before. 👍
This was so informative I learned a lot! I now know that there’s no good way of slowing down my single phase induction motor. I also know that a lot of people use vfd’s to convert 3ph motors to 1ph. How does this work? If a vfd is for varying frequency, how does it convert phases?
Hey, I watch your videos from time to time, and find them very informative... It so happens that I got an old bench grinder that works fine, and I would like to repurpose it to work on grinding/cutting, and polishing semi precious stones, as well as to work on other materials that may not be able to handle the full speed of the machine. My question: Is it safe or "ok" to add a potentiometer or dimmer switch to the grinder to achieve this? Thank you in advance for your response..
Great content easy to follow You should have a school so you could pass your knowledge on to others So many of the repair shops we go to now day have technicians but when they plug into something if it doesn’t give them an answer or tell them what part to change most of them are lost You have from the foundation and up This kind of knowledge is slowly disappearing
Hi, I actually have been using for many years a evap cooler with varied fan speed setting using a router speed control. It doesn’t seem to have any negative effect on the motor and it works great. It is a bon Aire cooler that was so extremely loud and the air volume was too intense. I toned it down with a simple router speed controller. Any comments welcomed. Thanks for your insight.
What about regulating the power with a set of different capacitors that are in line with the motor? This would of course only work under load. Different capacities would give you different amounts of power.
I know it has been quite some time since you posted this video, but if you have any interest in single phase vfd’s, check into submersible pump vfd’s, used often in the well drilling industry. Not sure what other applications you could modify it for, but interesting nevertheless
I took apart a small standing fan and noticed that it had 3 "load" wires, and the fan ran at different speeds depending on which one you connected. Based on what I've learned from your videos, it's an induction motor and I guess each of the 3 different wires changes how many poles are created. My question is where can I find a diagram of some sort that shows how the windings/coils are configured and wired up? I've googled incessantly trying to figure this out but I can't seem to find anything. My curiosity is insatiable and I'd very much like to understand exactly how they managed to wire this up to achieve different speeds. And thank you so much for making these videos!
You could try measuring the resistance of the different winding sets. That would at least give you something to map out. I'm sure they would be different.
Great demo. Thanks for the clear info. So if you have a kitchen range hood fan with 2 speeds and you want to reduce the speed then there's no way of doing it? I've seen some people use dimmers on shaded pole induction AC motors, but as I've seen here and other videos, it's not recommended as it reduces the life of the motor over time. I have a range hood fan that is 44 Watts on low, and is too loud for me. From my 'research' into shaded pole induction AC motors for fans, they are pretty limited, and the design seems like a compromise. Also, it seems range hood fans are generally too powerful for their application. I.e. over engineered for huge air flow movement, but not much good for low air flow movement. I would recommend at least 3 speeds if you are looking at one. Then you can at least use the lowest fan speed to minimise noise. I am talking your basic fixed range hood that is fitted below a shallow cupboard.
I watched several videos discussing dimmer switches and motors but your video by far had the best information density lol I started researching this because my dad's old vinyl record player still works, but it has no finite speed adjustment within each RPM setting. Just looking at the motor, I believe it is a 3-phase induction motor. Would using a dimmer switch (I imagine the record will serve as a mechanical load) be okay for finite speed adjustments? Say, in the order of a few RPM? Or would there still be ill-effects?
I learned about motor speed being changed by Hertz and not reducing voltage. I put a dimmer switch on the bathroom fan. And sure enough didn't take long and that motor burnt up
Great insight! Great Video! I've spent countless hours watching other channels like yours and most end up leaving me confused. I would like to know a simple and cheap yet solid way to build my own high voltage speed controller (mostly from parts pulled from other electronics) to control a 36V brushless hub motor pulled from a Zappy 3 e-scooter.
I have been studying this sort of thing for a few years, and I have watched other engineering and machining channels. I learned more in 5 minutes of your channel than ALL of the other channels in YEARS! You are a gifted teacher, thank you Jeremy.
+Victor Bingo thank you!
same here. I thought I knew what I was doing but learned more from his videos that any other source before
mcorrade it's like he filled in all the blanks I had.
Amen, Amen and AMEN!
This man KNOWS how to turn a high tech subject to a "piece of cake".
Any technical school would be a fool not to hire this man YESTERDAY.
He is a treasure for sure. May Jesus continue to gift him with knowledge that can be taught easily to the masses.
Victor Bingo q@zzzxxxssx Is r600tq
Ki
Brilliant. Instead of just saying "this won't work", you have actually shown us it won't work and you have explained why. Much appreciated.
Thanks, man! Sometimes you find EXACTLY what you were searching for on UA-cam and for me, this is one of those moments. Your video saved me a LOT of time, headache and money. Keep up the great work 👍
You explain the process that you went through to get the results that you did.
That's why your videos are so good for the common person.
You don't just tell us what to do, you show how you reached each point of the process.
Thanks Jeremy and keep up the good work.
Wow, never even though about the starter capacitor kicking back in at lower speeds. Thanks!
You are doing what you should be. Teaching is your genre because you are good at it. Very thorough and informative. Thanks.
This channel is so underrated!
+D Moore tell some friends!
I agree.
Dude is amazing
Agreed!
I agree with Victor.
You have seemed to say in 10 minutes what others do not even get around to saying in 10 hours in a way that can be understood
It's important to note that when you slow the motor down you also lose power. The torque on the rotor is determined by the strength of the magnetic field acting on it, which pretty much stays constant, leading to a loss of power (same torque at slower speed=less power).
This is a problem for machine tools since you want constant power throughout the speed range (for example a drill press, lathe, milling machine etc.), meaning torque needs to increase (NOT stay constant!) as speed decreases to keep the available power more or less the same.
Work done by a particular cutting tool moving past the material at X speed and at Y depth of cut is the same regardless of radius of action (small drill vs large, small milling cutter vs large, small diameter work piece in lathe vs a large one etc), therefore if the RPM is dropping (to keep the tangential speed constant), torque needs to increase for a constant force behind the cutting edge. Power is Force X distance/time, so constant force at the tool requires more torque as the radius of action increases (and constant tangential speed require less RPM as radius increases).
The only real solution is a mechanical reduction, i.e gears and pulleys, which multiplies torque proportionally as the speed decreases, keeping the power constant (more or less, ignoring some mechanical losses). Or, sufficiently oversize the motor that you still have enough power at the slowest speed you will be running it, but that's obviously not as efficient, and not nice to the motor.
There is NO magic solution, embrace mechanical reduction whenever you have it, even when you have a 3-phase motor with a VFD, so you can keep the motor running as close to its rated speed as possible, for maximum available power and a cool running motor (the motor fan also slows=less air flow!). I would love to build an external reduction gearbox/pulley system for my future lathe, to achieve very slow speeds at full power and have more speeds in between the stock speeds (be it a geared head lathe or a belt drive). I'm not a fan of slowing motors down at all, although a VFD with a big 3 phase motor would be nice for soft starts, quick stops, and moderate speed control between the different gear/pulley speeds.
Within seconds I realised you are a smart cookie who actually knows what you're talking about. That's rare on UA-cam. I didn't need to see another video, insta-subscribed!
My camera finally quit. Time to buy a new one! I will finish the "Question and Answer video" as soon as I can! I would love to know what kind of camera you all would recommend.
Jeremy Fielding Spony alpha7 with old Canon FD Lenses....beautiful!
Wow... that is top of the line!... I think I need more mid range lol
Value Village :)
I’m sitting here trying to figure how the speed control on a fan motor works and I’ve been racking my brain on it a triac style speed control would work!!! I’m so glad to have found your channel!
Hello! Thanks a lot for the great tutorial. My question is: Whats inside a variable speed power tool? Cant be that big of course.
Great Q!
Well they don’t use brushless induction motors. They use brushless dc motors (which uses pwm to control speed) and brushed dc motors (which uses voltage to control speed). Those are much easier and very compact speed controllers to manufacture
gifted teacher ..keep em coming ...everyone loves your flavor on these subjects ....what ever it is you have it .... thanks M from down under Australia 240v
Although you indeed can't dim an induction motor it does sound like it's not even starving the motor because the triac isn't turning off. Because the lacking of current with an inductive load it's hard to turn off a triac. So I think if you place a bulb parallel to the motor while using the dimmer it will not dim either because the triac isn't turning off :D
+tengelgeer now that sounds like an interesting experiment. I will try it and let you know what happens.
You have the best basic motor education videos I have seen. This video is about the most ask question ever and few explanations about this subject on youtube. And for whatever reason, there are few basic motor education videos in a real setting using real stuff that you would really find for cheap or free. This is a great video series you have about motors. Thanks.
Thank you
You are a very talented individual and teacher. I was able to follow and understand your message. I have subscribed and will visit this site often. Thank you for providing such good content.
You have done the absolute best job at explaining this exact topic that I've found yet... and I've been scouring the internets for a long while. Very good video, AWESOME demonstration! Thank you very much for this.
Thank you for letting me know. I actually made the video because so many viewers have asked about it, but when searching UA-cam and the internet, there was conflicting information and some things that were just wrong. This video has a part two as well if you are interested. ua-cam.com/video/JTlHNOaBnPI/v-deo.html
Oh I'm already subscribed and watching all your videos! You're awesome and so are your videos! (On a side note I actually found your video because I'm making a workshop of my own... I've been wondering if it was possible to change the rpm of my bench grinder... I'm still not 100 percent sure what the answer is, but I think it's a "no" or a "not worth it", after watching your videos I understand electric motors a whole lot more and now have a good introduction enough to be able understand more of the information out there on the internet in regards to these topics.) Thanks again!
... I'm pretty sure the answer is I can't because a VFD for single phase motors is rare and works only for very particular induction motors, and my motor is not one of those because it most likely has a start winding with a capacitor.... I stop understanding after that point... but I'll just go review your videos again.
It sounds like you nailed it! I am so glad you found it helpful. :)
Thank you for your excellent presentations. I have a 30 year old Thermador vr600 kitchen exhaust fan with a single phase 120 volt induction motor. It seized up and was able to repair it by lubricating the mounting bushings, no bearings. There was no capacitor and the motor turns on with a 360 degree rotary switch that graduates from high to continuously lower speeds without electronic speed control. Variable speed and no capacitor, how is this possible.
it's a universal motor, not an induction motor.
Thank you.
Someone designed my furnace with a three speed winding motor for variable speed and added a triac lamp dimmer in the controller to ensure failure. Luckily it was the triac that shorted with no motor damage.
Another great video Jeremy!
I'm an electrical engineer with 20+ years experience and I feel you produce excellent content. On another video you had mentioned speed control and I commented that a TRIAC PWM circuit will control the speed of an AC induction motor. I have designed the circuitry, tested it, and verified that it does change the speed of a fan, but that is a motor under load, unlike the motor in your test. I think that it is accurate, however, to say that in an applied, practical sense a TRIAC PWM circuit will control the speed of an AC induction motor because I've never had the need to control a motor that wasn't under a load. It's similar to testing amplifiers and seeing a high gain in testing that doesn't translate once the amplifier is driving an actual load that requires some impedance matching.
Please watch part two of this video
Jeremy Fielding These were huge industrial fans that used large AC induction motors with starting capacitors and belt-pulley mechanical translation between the motor and the fan axle. In fact, they were so large that we activated them with 5 - 6 inch wide contact switches that were themselves activated by relays and optical switches (to isolate industrial noise from logical circuits). We weren’t using a light dimmer switch. This circuit used a MAC224 40A TRIAC, so it wasn’t designed for indoor oscillating fan motors.
FINALLY an understandable explanation for why I can't dial down my grinder (induction) motor speed. Nice job!
I reckon you already know that you are one of, if not the smartest, people on UA-cam. Thank you for sharing your knowledge with us.
YOU JUST SAVED ME $28. WORTH THE PRICE OF VIEWING YOUR VIDEO...AND DONE WITHOUT BEING LADEN WITH COMMERCIALS. BRAVO! AWESOME! 👌💪🏽✅👀
You saved me a lot of money by showing what to avoid. Many thanks.
Great video... I found this when searching how to control a vibration motor for soil separation. Many videos have said buy this motor and a variable fan speed controller and it would work. But almost anyone that tried it made a comment under the video that it was either off or full speed... the controller didn't work. I believe your explanation just proved why. Sad, because I really believe I will need that variable control. Any direction you could point me would be appreciated. Thanks Again!
Thank you Jeremy so much for explaining this I've been trying to figure this out because I am building a metal lathe and I want to be able to control the speed without using a belt system or gears.
Thanks for the awesome explanation. I wondered why I couldn’t vary the speed of a motor I have, and. Now I understand. Glad we have intelligent people like you on here .❤️🤠
Thank you Jeremy for the clear information on how to reduced speed of motors. I have been having to sort out this issue for a month and now I know what can work and what won't.
I love this guy. Why can't they explain stuff this way in school? A lot more people would be interested in electricity and electronics. The way it's presented in school makes it seem like you have to be a genius or math wizard to understand technology. It turns out you just need a good teacher and some stuff to experiment with.
+Jeff Roberts thank you!
I am currently experiencing some issues with a pentek intellidrive VFD which can be used with 2 or 3 wire single phase 240v submersible pump motors. Specifically I am seeing voltages from the VFD which I can not wrap my head around. An engineer suggested that perhaps it is due to the PWM and possible lack of a low pass filter on my meter. Anyway it's a shame that this video isn't able to discuss the nuts and bolts of the single phase VFD just yet, however I am grateful for all the great information here and the clarity your videos have brought me on the the different characteristics of the various motor types. Thank you very much for your great videos.
I think you require a "true rms" multi meter. Normal meters are only designed to work at 50 or 60 hz, any freq outside this range such as what a VFD would output will result in incorrect readings
Jeremy, I can't tell you how much I enjoy your videos and how awesome I think you are. All I can do is thank you for the content. Thank you very much.
I get it, yaaaa! So if you change the number of peaks and valleys, or frequency, from 60 to 50 it goes slower. it's chasing fewer of these so it slows down. Great teacher, thanks Jeremy!
You were exactly right I did the same thing with the dimmer switch and got the same results thank you
Exactly what I was looking for. I learned a lot. I was thinking of trying the same router controller. Thanks for highlighting the warnings.
Very good information. I was looking at ways to lower my drill motor speed and you’ve cleared up a lot of questions.
Thank you, have made a tumbler out of an old gas dryer. Ideally we wanted the drum to turn slower. Presently at about 50 RPM. You just saved us a whole lot of head scratching - the plan was to try a dimmer switch. ....Life is still good though. Thanks for the video!
So basically for all common cheapo single phase induction motors, stay safe and use a system of pulleys or gears? Fancy speed control stuff for 3 phase motors, go VFD. Good video and explanation! Maybe I can start thinking about building a metal cutting band saw or belt sander.
I can’t believe that I actually understood what this man just explained. You know that old stupid saying’ those who can, do. Those who can’t, teach. Well Jeremy, you just sent that old worthless piece to its eternal grave as far as I’m concerned… thank you!
Ps: VFD’s are the only way to compensate for a variety of ‘load’ changes in a variety of systems.
Well done.
You're the best, this is my new favorite channel
"A vfd is the only proper way to vary the speed of an induction motor." Thanks a lot for that bro! \m/
All the other way that are there on the internet are probably for views or theoretical "flaunting" i guess, because neither do they work without damaging the system nor are they used anywhere especially for professional and commercial purposes..
great job
Someone installed fan speed controller (looks like a light dimmer) at church. I asked him how much he paid for it, he said about 50 dollars. Seems like they make a speed controller for an induction motor. I am curious what is inside them. Excellent video btw, I didn't know that reducing the voltage doesn't affect the speed of an induction motor (under no load conditions).
Your videos are outstanding. Thank you for taking the time to make them!
I hope you still read comments on 4 year old videos, Jeremy. I’m wondering if you could make a DIY VFD for single phase motors (and teach us all how to do it)? There’s probably a reason that they’re impossible to find but I have great faith in your ability to pull this off! ; ) Who knows, there could be a business opportunity for you in this! (I.e. having these VFDs manufactured (overseas somewhere) to your design specs.)
Thx for clearing my head with a clear and precise explanation.
I'm in the fitness equipment industry and I've been trying to find a way to test the 3 phase AC drive motors in treadmills...I guess I need a VFD with a potentiometer! You should do a video on that set up you have there!
As grownups go, you are pure gold. Thanks once again.
Great video. Just a quick note. Make sure that the motor that you're using with a vfd is "inverter duty". VFDs create high voltage spikes and insulation can fail faster (less motor life) if it's not designed for the higher voltage.
Also cooling is a problem now that the fan is running slower. In general that will damage the motor sooner then later. Definitely worth mentioning.
Most practical illustration. Thanks.
Very good explanation. Regards, Engineer/Professor from India.
excellent video. practical for industrial applications. thank you for making this!
Thank you for your excellent content. Clear, concise and very thoroughly explained. Again, thank you.
This is gold info. Thank you very much man. Very appreciated!
I’ve been working on a single phase drive (motor driver) for a long time. I haven’t had enough time to devote to it. But, I’ll get serious and will let you know when I have it. There probably isn’t a way to do a “one size fits all”, but there is a way for those who are qualified to build something which could become dangerous for those who don’t have the background in higher power devices to play with them. The power coming from AC/mains outlets is beyond a kilowatt! Sometimes two or more Kw.
That was interesting. We built a label roller out of an old B&D drill running off a dimmer switch to control the speed. It worked, but you had to start fast, then dial it back to the desired speed. Since the printer only went so fast, we used a rubber mini drum sander piece to fit in the core, to let it slip if it got going to fast for the printer on start up. I didn't want to pull the labels through the printer before they had a chance to print. Mind you, we used a Dymo printer for 4x6 shipping labels, printing all 250 labels in one step. Each new label, would pull the roll back to the registration mark, then print the next. It worked flawlessly, so long as you had the drill running in the right direction. Since we started winding them on an old label core, controlling the speed of the motor was necessary, as the more the roll gathered, the slower the drill needed to run. I think we printed around 40,000 labels using this method.
I really appreciate this. Learned a lot on this video alone. Keep it up Jeremy, you're new sub here
Your a wise electrical engineer,,, I'm working on my friends yath has heatpump,,it's a 89 boat,,had potentiometer slide control for fan speed,,they changed system a few years ago,,,my concern is the old thermostat is going to burn out induction motors,,,one was gone when he bought the boat,,and I noticed a loud hum
7:40 you can find a 120v 1ph input 240v 1 and 3ph output vfd that goes up 320hz, i have one, bought from aliexpress i think. $280.
Thanks! I wish I would have paid more attention in electronics class.
love it you give a great full but simplified explanation covering lots of variables also seem to have a courious mind like mine
They do make a single phase freq drive for air conditioner condenser fan motors. They are used in conjunction with a thermistor to control head pressure. If you could get ahold of one, you could replace the thermistor with a potentiometer. However as I understand it you must only use a single phase freq drive on a motor with ball bearings because it will elongate sleeve bearings.
Interested to know where you got your VFD. They're quite expensive from Amazon (compared to the free washing machine motor).
I thank you for making this video, already learned allot and I'm sure I'll have more to watch & learn from you!
Thanks for making this video. I have a much better understanding of just how a electric motor works. Again, thanks for taking the time to make this video. :-)
Fabulous Information
You have an excellent speaking style, and I appreciated your demonstrations, and found your explanations to be clear and understandable. Well Done! Definitely subscribing.
Welcome to the neighborhood!
Great video; I use a variac for my bedroom fan and it seems to work fine, but a triac control causes buzzing that is annoying.
There is a part two about fans
Thanks for pointing that out.
Great stuff brother keep the dream going. Great information and presentation
you can get single phase VFD's especially at low power levels. it is also possable to modify certain single phase motors to accept a 3 phase input but it will result in an unbalenced load of the need for external componants.
Great video! I am having some trouble slowing down a 12amp brushed Harbor Freight Pipe Threader. I am using the threader as a power source for a sheet metal bead roller. It works good, but a little too fast. I purchaser a Router Speed control like you show in your video. The threader does not have variable speed in the switch and is a brush type 110v AC motor. The threader is 12amp but I assume that is under load, but I could be wrong on how that works. I get absolutely no effect using the Router Speed Control. I did plug my 4 grinder in and it kind of made in run slower but choppy. Thanks
Your techical explanation was great. I was just about to try this myself. I understand that many 3 phase vfd will run split phase or single phase induction motors as long as there is no start switch or start capacitor.
oops. Thie first link I found was this discussion. www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/single-phase-motors-may-run-off-vfds-177077/.
I will try to locate the vfd products I was looking at a while back.
Here is one. bardac.com/ac-drives/ .... Scroll down until you see E3 series - single phase
Here is a cheap alternative if you have the ability to build a circuit. www.homemade-circuits.com/single-phase-variable-frequency-drive/
Oh I watched that one a while back I should go back and watch it. Thank you #Jeremy your videos have inspired me to dream big and be resourceful. It's a whole new world I haven't discovered yet.
Your channel came up on my recommended videos, looks interesting and informative, just watched the one on varying induction motor speeds, something I'd not really thought about before. 👍
Welcome to my neighborhood!
Thanks you so much. Here I found the conclusive info about regulating the speed of an Electric Motors.
JAZAKALLAHU KHAYRAN
I love how you explained this, you made it much easier to understand what happens. New Sub here. Hope all your videos are like this.
Linrox Thank you... and Welcome the neighborhood!
Wow Jeremy!!! Your an amazing teacher and 100% brilliant. Thanks & Keep up your greatness.
👍
This was so informative I learned a lot! I now know that there’s no good way of slowing down my single phase induction motor. I also know that a lot of people use vfd’s to convert 3ph motors to 1ph. How does this work? If a vfd is for varying frequency, how does it convert phases?
this is a great video. The formulae explains plenty.
Hey, I watch your videos from time to time, and find them very informative... It so happens that I got an old bench grinder that works fine, and I would like to repurpose it to work on grinding/cutting, and polishing semi precious stones, as well as to work on other materials that may not be able to handle the full speed of the machine. My question: Is it safe or "ok" to add a potentiometer or dimmer switch to the grinder to achieve this?
Thank you in advance for your response..
Very informative video, excellent presentation.
would love if you made a video of all the types of motors and how to tell the difference.your a genies
This is a topic I have been working on.
Great content easy to follow
You should have a school so you could pass your knowledge on to others
So many of the repair shops we go to now day have technicians but when they plug into something if it doesn’t give them an answer or tell them what part to change most of them are lost
You have from the foundation and up
This kind of knowledge is slowly disappearing
You certainly know your stuff .brill video 👍👍👍👍eric hart from the uk 🇬🇧
Hi, I actually have been using for many years a evap cooler with varied fan speed setting using a router speed control. It doesn’t seem to have any negative effect on the motor and it works great. It is a bon Aire cooler that was so extremely loud and the air volume was too intense. I toned it down with a simple router speed controller. Any comments welcomed. Thanks for your insight.
Once again another very informative video! Thanks Jeremy!
Great explanation. I'd love to see an explanation of dc motor speed control. Thanks!
Well done. You would be an excellent teacher.
Dude, I can't tell you how helpful this was!! Additionally it is SOOOO GOOD to see a fellow African American on UA-cam preaching knowledge.
Thanks for the free education, bro!
What about regulating the power with a set of different capacitors that are in line with the motor? This would of course only work under load. Different capacities would give you different amounts of power.
I know it has been quite some time since you posted this video, but if you have any interest in single phase vfd’s, check into submersible pump vfd’s, used often in the well drilling industry. Not sure what other applications you could modify it for, but interesting nevertheless
I took apart a small standing fan and noticed that it had 3 "load" wires, and the fan ran at different speeds depending on which one you connected. Based on what I've learned from your videos, it's an induction motor and I guess each of the 3 different wires changes how many poles are created. My question is where can I find a diagram of some sort that shows how the windings/coils are configured and wired up? I've googled incessantly trying to figure this out but I can't seem to find anything. My curiosity is insatiable and I'd very much like to understand exactly how they managed to wire this up to achieve different speeds. And thank you so much for making these videos!
You could try measuring the resistance of the different winding sets. That would at least give you something to map out. I'm sure they would be different.
Great demo. Thanks for the clear info.
So if you have a kitchen range hood fan with 2 speeds and you want to reduce the speed then there's no way of doing it?
I've seen some people use dimmers on shaded pole induction AC motors, but as I've seen here and other videos, it's not recommended as it reduces the life of the motor over time.
I have a range hood fan that is 44 Watts on low, and is too loud for me.
From my 'research' into shaded pole induction AC motors for fans, they are pretty limited, and the design seems like a compromise.
Also, it seems range hood fans are generally too powerful for their application. I.e. over engineered for huge air flow movement, but not much good for low air flow movement.
I would recommend at least 3 speeds if you are looking at one. Then you can at least use the lowest fan speed to minimise noise. I am talking your basic fixed range hood that is fitted below a shallow cupboard.
nice video, Jeremy,thanks for sharing.
I watched several videos discussing dimmer switches and motors but your video by far had the best information density lol
I started researching this because my dad's old vinyl record player still works, but it has no finite speed adjustment within each RPM setting. Just looking at the motor, I believe it is a 3-phase induction motor. Would using a dimmer switch (I imagine the record will serve as a mechanical load) be okay for finite speed adjustments? Say, in the order of a few RPM? Or would there still be ill-effects?
Cool you answered my question drills have brushes
I learned about motor speed being changed by Hertz and not reducing voltage. I put a dimmer switch on the bathroom fan. And sure enough didn't take long and that motor burnt up
Great insight! Great Video! I've spent countless hours watching other channels like yours and most end up leaving me confused. I would like to know a simple and cheap yet solid way to build my own high voltage speed controller (mostly from parts pulled from other electronics) to control a 36V brushless hub motor pulled from a Zappy 3 e-scooter.
Dude,great video... i was going to wreck mi belt sander using a dimmer.. thanks a lot
Awesome video and explaining the details. What would you suggest to limit in rush current on a single phase induction motor?