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.
About 30 seconds in I knew I had hit gold. You are indeed a gifted teacher. i will be watching more and more of your material in the future. 65 year old multi skilled construction guy from UK. Many thanks.
Jeremy, May I add to the applause given by so many others. I have been trawling the internet for knowledge on AC motors and their control and operation, 10 minutes with you has been a revelation! I also watched some of your other videos. You are a great tutor. Thank you. You deserve more recognition.
Dude, every single time I go looking for unique electric motor information, people ALWAYS link back to you.... And damn it am I grateful they do! You really know your stuff and have explained LOTS to me, including understanding perpetual energy and the physics debunking so much of the videos you see online. You are AWESOME man! As a guy with hardcore ADHD, I get forgetful all the time, but you really help me. You explain things in a way that I can retain so much. If I could only remember to come to your page first when I have a question, that would be great! But again, ADHD....... Thank god everyone links back to the one guy who really knows his stuff, YOU!
Jeremy, this is possibly the finest, best demonstrated video I've seen on the subject of "Is it possible to change a motor's speed with a dimmer switch, etc." I give you a hearty two thumbs up!!
Your never to old to learn... You have just schooled me! I honestly didn't know how they were controlling the speed on induction motors! Outstanding video! 👍😁
Thanks, man! Sometimes you find EXACTLY what you were searching for on RUclips 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 👍
Man! What are you? An engineer? You are so well informed and speak so intelligently and have your demonstrations so well organized! Thank You! I am an electrician and love the re-view. I am sure I have forgotten a lot. Excellent work and please continue.
Thank you for all you do here brother, you’re an amazing engineer and a gifted teacher. It’s my opinion that for many of us fortunate enough to possess “the gift” of “innate understanding” we often times forget to appreciate this skill and remember to use it to help others find what some are gifted with. It’s not always easy to do for the “hyper analytical”, and technical mind. So I thank you for reminding me it should always be shared, I salute you sir, you win at life man. 07
Within seconds I realised you are a smart cookie who actually knows what you're talking about. That's rare on RUclips. I didn't need to see another video, insta-subscribed!
Great vids Jeremy. Just one comment I would like to make is, it would be great to see the volts and amps ( and possibly even Hz and rpm also) in real time in some of these videos as well for added perspective of what is actually happening in the circuits. Love your stuff, keep it up, very educational.
Thanks for that really good explanation - I understand the issues now. Now I KNOW I am no further forward - I need to cut mild steel accurately, I have to choose between using an abrasive disk and making a mess, or using a TCT disk and wrecking it. Which raises the question, why does nobody make a DIY mitre saw with a low speed option that can be used for cutting steel? It's something loads of people want to do.
Jeremy you are the current day Tony Stark lab workings. Your videos have taken the guessing game out of a complex working motor and enabled others to quickly understand . Thanks for your help.
U DA MAN!! Thanks Jeremy that really clears up all my misunderstanding about speed control, VFD and induction motors. I now realize ALL my issues and what I can and cannot do. These edu vids are greatly appreciated
Im surprised you're not more popular. Very informative, clearly articulated without an overwhelming personal thirst for being flashy. I barely comment nor subscribe but I found you so informative that I had to credit your efforts.
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 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.
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 RUclips 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. ruclips.net/video/JTlHNOaBnPI/видео.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.
I've spent countless hours reading, looking at diagrams and formulas only to feel like I grasped a tiny portion and still not completely understanding why certain things work and don't. You have taught me more in 20 minutes than I've learned in hours of reading. That router speed controller in the exact one I was trying and left confused why it wouldn't work. Thank you. 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.
So I'm building a lathe and I wanted to control the speed. Having experience with DC steppers and achy servos I understood some basics. A friend was asking if he could use a 1/3 how motor and a fan switch. This video was the best way to explain that you can't. I pointed him in the direction of a nema stepper and a driver/ breakout board. Thanks for your video very helpful!
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
I've googled this topic for quite sometime and have a faint idea about it. 5 minute watching your video made it so much clearer, especially on why i cant find single phase VFD 😅
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.
Jeremy, This is one of your best videos. Thanks to you, I have a better understanding of motors. I have a question I hope you may be able to answer. My wife and I bought a vacuum cleaner when we were in Japan, and as you may or may not know, it has ~100 -110 VAC, 50 Hz coming in to the inlets. If I plug the vacuum cleaner in a 120 VAC, 60 Hz inlet, the vacuum may work a short time but turn off. At first I thought it was a fuse or something blown, but then I thought, plug it into a step-down transform... It worked. The vacuum cleaner says that it will work on 100 VAC, 50/60 Hz. The average volt when I checked it when we were there was 110 VAC and the vacuum worked. Any thoughts on what maybe going on? Thanks!
I was thinking the same thing, because it only about a 10%, give or take. I just took the volts reading from the incoming, 122 VAC, Step-down output 105 VAC (13.9344% difference). I will crack that thing open and see what's going on. I am also thinking there maybe a current or voltage limiting circuit inside. Thanks.
4 years late I know but may have to do with the frequency. I've been looking into an imported compressor being sold here in Barbados on special, turns out it's on sale because the 2hp single phase motor was intended to run on 115v 60hz, however the motor gets hot on our system which is 115v 50hz. For most 60hz appliances with motors or compressors e.g refrigerators, washing machines, treadmills, AC unit, etc, we usually use a transformer to step the voltage down 115v to 105v, most common is the 1000VA version. It's referred to locally as a stabilizing transformer but doesn't seem anymore different from what is online labeled as step-down, autotransformer or voltage reducing transformers. I never gave the need for them a second thought until the compressor sale. My research for something powerful enough or other options like inverters etc led me to understand that lowering or raising the voltage affects the Volts/Hz ratio. Google it for a better understanding of how a few volts less affecs frequency, speed and cooling, torque etc
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.
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
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!
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.
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.
Subscribed. I wanted to know what to do with the giant stack of variable transformers I have. Now I know I can't use them for speed controllers on induction motors. Very well explained, Jeremy. This is RUclips gold.
Clearly explained, so easy to understand when someone knows exactly what they are talking about! Hope this guy's a teacher in university, if not he should be! Thanks for the education.
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!
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.
Always high quality tuition on this channel. Perfect combo of essential detail, logical sequencing and hits the most common misconceptions most people have. When people really know an area they can distill the essence. Well done.
Top video,excellent explanation in plain english.I have been looking for a single phase VFD but no one makes them probably for the reason you stated here.Keep up the great work,I am now a subscriber.
Hi, I am building a 72-inch grinder and have 3 motors to choose from, I have been looking for a single phase VFD but couldn't find 1 and I know why from this video you are my go-to guy for electrical projects. Thanks, for explaining in plain English
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
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!
I had a conversation this week over this very topic when a friend and I were looking at a single speed electric motor. I wanted to do something external to the motor to change the speed quickly, perfect for a lathe. You reinforced exactly what he said, so we will go another way. thank you for the great presentation.
You should have said, that many of the VFDs have a single phase input, so its easy to change a single phase motor to a 3-phase-motor and have the possibillity, without the need of a 3-phase-connection in the house, to adjust the rpm of the motor. But you make great info-videos. Many can learn from your instructions. Keep on the good work. Sorry, english not my mother language. Regards from Germany.
Originally I was going to show the label and mentioned it was single phase input three phase output... but the video was a bit too long so it fell on the cutting board. I agree that would be a good addition though.
I've been trying to find a way to slow down a bench grinder. Thanks for confirming my findings. No other way other than 3 phase and a VFD... Great video.
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 .❤️🤠
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.
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
Hey man! As they say it's not enough to have it taught. One's gotta be able take in the teaching!. And you mastered it. To the point that you can teach it now.. You got skills to convey the message at hand! Nicely done!
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.
Did I found this topic helpful? Huuum … Let see : A LOT!!!! FINALLY, I UNDERSTAND WHATS HAPPENING!!!!THANK YOU!!! God, I was wondering for such à long time what was the problem with those dimmers. Now I know. Thank you very much.
Good information - thanks! In Mr Carlson’s Lab on YT, he designed a VFD for a single phase induction motor in a Hakko desoldering station. He went from the normal 60Hz operating frequency to 90Hz in order to increase the vacuum.
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.
I have that exact same washer motor. I'm making that washer into at least 3 heavy duty power tools. At least one of them is one I haven't seen you make yet. I hope my projects can be as entertaining and informative as yours
Excellent demo. Motors were never my strong suit. I appreciate this. It tells me something about those variable speed drill motors now & them being a brush type design.
I was highly impressed to say the least. You make learning this type of thing fun and I appreciate all your work compiling the stuff you need for a great video.
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!
Short answer: NOPE Thanks for the video. Short and concise. Been looking for means to add variable speeds to an AC motor and this saved me from making a mistake.
Wow, you do a great job of educating those who want to use alternative, cheaper motors in different applications. I am trying to wire up a 1/6 hp oil burner motor to power a flat lap for polishing stones. I have used toggle switches before but I was trying to put a led three pin rocker switch on this motor and I was wondering if you have done a video going over different types of toggle and rocker switches? Thanks for making sense of electric motors and saving us cents at the same time.
Great video. I have been hunting for a single speed VFD, as well. I should have known better! (I have been dealing with AC/DC circuits since I was 5.) I just got so used of typing what I need into Google and getting an answer.
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.
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.
Thank you, Jeremy. You saved me hours of research looking for a product that doesn't exist.
Check out Mr Carlsons Lab where he shows how to build a single phase motor VFD from scratch with cheap and common components.
@@SkippiiKai, cool! I will find it and have a look. Thank you.
About 30 seconds in I knew I had hit gold. You are indeed a gifted teacher. i will be watching more and more of your material in the future.
65 year old multi skilled construction guy from UK. Many thanks.
Jeremy, May I add to the applause given by so many others. I have been trawling the internet for knowledge on AC motors and their control and operation, 10 minutes with you has been a revelation! I also watched some of your other videos. You are a great tutor. Thank you. You deserve more recognition.
Dude, every single time I go looking for unique electric motor information, people ALWAYS link back to you.... And damn it am I grateful they do! You really know your stuff and have explained LOTS to me, including understanding perpetual energy and the physics debunking so much of the videos you see online. You are AWESOME man! As a guy with hardcore ADHD, I get forgetful all the time, but you really help me. You explain things in a way that I can retain so much. If I could only remember to come to your page first when I have a question, that would be great! But again, ADHD....... Thank god everyone links back to the one guy who really knows his stuff, YOU!
Jeremy, this is possibly the finest, best demonstrated video I've seen on the subject of "Is it possible to change a motor's speed with a dimmer switch, etc." I give you a hearty two thumbs up!!
This videos has to be the most clearly explain speed control for an induction motor I have seen yet.
This channel is so underrated!
+D Moore tell some friends!
I agree.
Dude is amazing
Agreed!
Your never to old to learn... You have just schooled me! I honestly didn't know how they were controlling the speed on induction motors! Outstanding video! 👍😁
Thanks, man! Sometimes you find EXACTLY what you were searching for on RUclips 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 👍
Man! What are you? An engineer? You are so well informed and speak so intelligently and have your demonstrations so well organized! Thank You! I am an electrician and love the re-view. I am sure I have forgotten a lot. Excellent work and please continue.
+Lonefeather you bet I will. Thank you!
Thank you for all you do here brother, you’re an amazing engineer and a gifted teacher. It’s my opinion that for many of us fortunate enough to possess “the gift” of “innate understanding” we often times forget to appreciate this skill and remember to use it to help others find what some are gifted with. It’s not always easy to do for the “hyper analytical”, and technical mind. So I thank you for reminding me it should always be shared, I salute you sir, you win at life man. 07
Within seconds I realised you are a smart cookie who actually knows what you're talking about. That's rare on RUclips. I didn't need to see another video, insta-subscribed!
Great vids Jeremy. Just one comment I would like to make is, it would be great to see the volts and amps ( and possibly even Hz and rpm also) in real time in some of these videos as well for added perspective of what is actually happening in the circuits. Love your stuff, keep it up, very educational.
👍
Thanks for that really good explanation - I understand the issues now. Now I KNOW I am no further forward - I need to cut mild steel accurately, I have to choose between using an abrasive disk and making a mess, or using a TCT disk and wrecking it.
Which raises the question, why does nobody make a DIY mitre saw with a low speed option that can be used for cutting steel? It's something loads of people want to do.
Just extremely excellent stuff! A+. You have a powerful gift for teaching.
You have an amazing blend of theoretical and hands-on knowledge. I've seen people who are good at one, but being good at both is rare and impressive!
I find this very helpful and entertaining! Between you, AVE and Great Scott i am always entertained and learning new ideas. TY ;-)
+Klaus Nielsen you bet. Thank you for letting me know :)
Jeremy you are the current day Tony Stark lab workings. Your videos have taken the guessing game out of a complex working motor and enabled others to quickly understand . Thanks for your help.
U DA MAN!! Thanks Jeremy that really clears up all my misunderstanding about speed control, VFD and induction motors. I now realize ALL my issues and what I can and cannot do. These edu vids are greatly appreciated
Im surprised you're not more popular. Very informative, clearly articulated without an overwhelming personal thirst for being flashy. I barely comment nor subscribe but I found you so informative that I had to credit your efforts.
Thank you so much I am honored
Wow, never even though about the starter capacitor kicking back in at lower speeds. Thanks!
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
Excellent video.
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.
Jeremy thanks for all your help great video.
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 RUclips 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. ruclips.net/video/JTlHNOaBnPI/видео.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. :)
Love your videos. They have taught me more about motors than I thought I would ever understand.
I've spent countless hours reading, looking at diagrams and formulas only to feel like I grasped a tiny portion and still not completely understanding why certain things work and don't. You have taught me more in 20 minutes than I've learned in hours of reading. That router speed controller in the exact one I was trying and left confused why it wouldn't work. Thank you. 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.
So I'm building a lathe and I wanted to control the speed. Having experience with DC steppers and achy servos I understood some basics. A friend was asking if he could use a 1/3 how motor and a fan switch. This video was the best way to explain that you can't. I pointed him in the direction of a nema stepper and a driver/ breakout board. Thanks for your video very helpful!
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
I've googled this topic for quite sometime and have a faint idea about it. 5 minute watching your video made it so much clearer, especially on why i cant find single phase VFD 😅
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.
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
Fascinating. It answers some questions I've though about, and you explained it in a very effective way. Thanks.
I learned more in 10 minutes than i did in two hours of googling. Subscribed. .
Jeremy,
This is one of your best videos. Thanks to you, I have a better understanding of motors. I have a question I hope you may be able to answer. My wife and I bought a vacuum cleaner when we were in Japan, and as you may or may not know, it has ~100 -110 VAC, 50 Hz coming in to the inlets. If I plug the vacuum cleaner in a 120 VAC, 60 Hz inlet, the vacuum may work a short time but turn off. At first I thought it was a fuse or something blown, but then I thought, plug it into a step-down transform... It worked. The vacuum cleaner says that it will work on 100 VAC, 50/60 Hz. The average volt when I checked it when we were there was 110 VAC and the vacuum worked. Any thoughts on what maybe going on? Thanks!
I am not sure. I would not expect 10 volts to make a difference. How much did you have to lower the voltage? Also, does it seem to be getting hot?
I was thinking the same thing, because it only about a 10%, give or take. I just took the volts reading from the incoming, 122 VAC, Step-down output 105 VAC (13.9344% difference). I will crack that thing open and see what's going on. I am also thinking there maybe a current or voltage limiting circuit inside. Thanks.
4 years late I know but may have to do with the frequency. I've been looking into an imported compressor being sold here in Barbados on special, turns out it's on sale because the 2hp single phase motor was intended to run on 115v 60hz, however the motor gets hot on our system which is 115v 50hz. For most 60hz appliances with motors or compressors e.g refrigerators, washing machines, treadmills, AC unit, etc, we usually use a transformer to step the voltage down 115v to 105v, most common is the 1000VA version. It's referred to locally as a stabilizing transformer but doesn't seem anymore different from what is online labeled as step-down, autotransformer or voltage reducing transformers. I never gave the need for them a second thought until the compressor sale. My research for something powerful enough or other options like inverters etc led me to understand that lowering or raising the voltage affects the Volts/Hz ratio. Google it for a better understanding of how a few volts less affecs frequency, speed and cooling, torque etc
I reckon you already know that you are one of, if not the smartest, people on RUclips. Thank you for sharing your knowledge with us.
Another great video Jeremy!
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!
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 are doing what you should be. Teaching is your genre because you are good at it. Very thorough and informative. Thanks.
Man, you're smarter than a whole treefull of owls!👍😎
Good job!
What kind of owls?
Sir...Every project you make, you teach us, more and more. Keep on educating us, your student. 👍🏻👍🏻 :) Thank you.
Thank you!
Top Notch.
Thanks.
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!
I used to think I was somewhat smart.
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.
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.
Subscribed. I wanted to know what to do with the giant stack of variable transformers I have. Now I know I can't use them for speed controllers on induction motors. Very well explained, Jeremy. This is RUclips gold.
Clearly explained, so easy to understand when someone knows exactly what they are talking about!
Hope this guy's a teacher in university, if not he should be!
Thanks for the education.
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!
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 :)
Always high quality tuition on this channel. Perfect combo of essential detail, logical sequencing and hits the most common misconceptions most people have. When people really know an area they can distill the essence. Well done.
Watching this video saved me a great deal of time in my endless search for a single phase vfd controller. Thanks
FINALLY an understandable explanation for why I can't dial down my grinder (induction) motor speed. Nice job!
Great way to convey confusing information. Your explanation makes so much sense! Thank you!
I as well have been doing research on this for a belt sander. Thank you for the knowledge my man.
Finally! the answers to my questions ! So now I am going to have to figure out how a variable speed drill works.
Top video,excellent explanation in plain english.I have been looking for a single phase VFD but no one makes them probably for the reason you stated here.Keep up the great work,I am now a subscriber.
YOU JUST SAVED ME $28. WORTH THE PRICE OF VIEWING YOUR VIDEO...AND DONE WITHOUT BEING LADEN WITH COMMERCIALS. BRAVO! AWESOME! 👌💪🏽✅👀
Hi, I am building a 72-inch grinder and have 3 motors to choose from, I have been looking for a single phase VFD but couldn't find 1 and I know why from this video you are my go-to guy for electrical projects. Thanks, for explaining in plain English
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
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!
I had a conversation this week over this very topic when a friend and I were looking at a single speed electric motor. I wanted to do something external to the motor to change the speed quickly, perfect for a lathe. You reinforced exactly what he said, so we will go another way. thank you for the great presentation.
You should have said, that many of the VFDs have a single phase input, so its easy to change a single phase motor to a 3-phase-motor and have the possibillity, without the need of a 3-phase-connection in the house, to adjust the rpm of the motor. But you make great info-videos. Many can learn from your instructions. Keep on the good work. Sorry, english not my mother language. Regards from Germany.
Originally I was going to show the label and mentioned it was single phase input three phase output... but the video was a bit too long so it fell on the cutting board. I agree that would be a good addition though.
No problem, i'm sure, you will be flooded with questions about this theme. There you can add this info. Cheerio.
I'm no electrician, your easy to follow explanations on this subject are brilliant.
I've been trying to find a way to slow down a bench grinder. Thanks for confirming my findings. No other way other than 3 phase and a VFD...
Great video.
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 .❤️🤠
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.
You just saved me a lot of wasted money. So glad I found this video before I bought something that wouldn’t have worked.
You saved me a lot of money by showing what to avoid. Many thanks.
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
Fantastic demo and explanation! Do you have a source for an affordable vfd?
You make really good videos. I like the way you explain the function of electrical devices, and different way to utilize them !
As grownups go, you are pure gold. Thanks once again.
I really enjoy your channel. I just like to learn about different ideas. You are very knowledgeable and interesting to learn from.
Hey man! As they say it's not enough to have it taught. One's gotta be able take in the teaching!. And you mastered it. To the point that you can teach it now.. You got skills to convey the message at hand! Nicely done!
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.
Did I found this topic helpful? Huuum … Let see : A LOT!!!! FINALLY, I UNDERSTAND WHATS HAPPENING!!!!THANK YOU!!! God, I was wondering for such à long time what was the problem with those dimmers. Now I know. Thank you very much.
Good information - thanks!
In Mr Carlson’s Lab on YT, he designed a VFD for a single phase induction motor in a Hakko desoldering station.
He went from the normal 60Hz operating frequency to 90Hz in order to increase the vacuum.
Increasing speed is not a problem. Lower is what creates the problems. Faster means you will have less torque but that doesn’t hurt his project
Good video brother.thanks
[PAKISTAN]
Thks Jeremy ..you make complicated issues look so simple and hats off for all your simple and clear explanations and solutions
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.
I have that exact same washer motor. I'm making that washer into at least 3 heavy duty power tools. At least one of them is one I haven't seen you make yet. I hope my projects can be as entertaining and informative as yours
Excellent demo. Motors were never my strong suit. I appreciate this. It tells me something about those variable speed drill motors now & them being a brush type design.
I was highly impressed to say the least. You make learning this type of thing fun and I appreciate all your work compiling the stuff you need for a great video.
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!
Dude, I can't tell you how helpful this was!! Additionally it is SOOOO GOOD to see a fellow African American on RUclips preaching knowledge.
Short answer: NOPE
Thanks for the video. Short and concise. Been looking for means to add variable speeds to an AC motor and this saved me from making a mistake.
Great video. Note dimmer cuts voltage on for a part of the 60 Hz sine wave. The larger percentage ON, the brighter the light.
Who the hell dislikes your videos... These are amazing demonstrations and explanations! Keep it up :)
Wow, you do a great job of educating those who want to use alternative, cheaper motors in different applications. I am trying to wire up a 1/6 hp oil burner motor to power a flat lap for polishing stones. I have used toggle switches before but I was trying to put a led three pin rocker switch on this motor and I was wondering if you have done a video going over different types of toggle and rocker switches? Thanks for making sense of electric motors and saving us cents at the same time.
Great video. I have been hunting for a single speed VFD, as well. I should have known better! (I have been dealing with AC/DC circuits since I was 5.) I just got so used of typing what I need into Google and getting an answer.
it works 100% not to worry folks!! i did this with my wood router - hooked it up to a dimmer and works great!
excellent video. practical for industrial applications. thank you for making this!
Very nice practical explanation, saved me a lot of trouble.
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.