How the starter circuit on single phase induction motors works (capacitor start and resistive start), and how to reverse them. woodgears.ca/motors/reversing....
Hands down this is the best video on RU-vid. No stupid music, perfectly clear explanations and real world examples. I have a whole house fan that I need to reverse and now I have 100% confidence in my ability to at least check if it is possible. I knew little about single phase motors before seeing this. Now I totally understand them. Thank you.
Even though I have a bachelor degree in Electrical Engineering and my profession is designing electronics, I found this video to be very interesting and informative. Thank you for taking the time to make it!
I want to thank you for teaching me how to reverse old electric motors. I finally got around to put in a reversing switch on my drill press. You explain the process a lot better than other people who tell us how to reverse drill press motors. My 1937 Delta drill press with a Westinghouse motor was easier than I expected. Once I open the cover on the motor there's only two terminals where the power wires went in and other wires came off of the windings and I just reverse those two wires that went into the windings to make it run backwards. I put a four gang box on the drill press with three switches, one for the motor, one for the light, and a 4 way wall switch to reverse the motor. My old drill press lacks a few features I wish it had but it was fun putting this feature on it. Now I just need to find a light for it that looks vintage.
About reversing single phase induction motors, and how the starter circuit works. woodgears.ca/motors/reversing.html (and there are still a few induction motor topics left to cover!)
Matthias Wandel That is starting to make a LOT more sense now. I have two washing machine motors, one of which I hope to turn one into a table saw one day and wondered why they had a beefy capacitor on them. Keep the videos on this topic coming ;)
Matthias Wandel Another way to reverse a single phase motor: remove the capacitor, wind a string on the pulley in appropriate direction, pull hard on it to get it spinning and switch AC on shortly after. It will happily spin in the other direction but only by mechanical start.
Wayne Johnson Probably. But potential can be wound back. The first step is to get the motor moving correctly. Then I'll worry about ratios and torque later ;)
Finally, a woodworking use for an oscilloscope! I knew there had to be an application, and if anyone would find it, it would be you. Another great and informative video - thanks Matthias.
Perfect explanation of the exact puzzle we've been struggling with at my work. Can't wait to get to work in the morning and share with the guys. Thank you Matthias!
This is why I like your videos, Matthias. You can explain things that I have little knowledge about in terms that make it easier to understand. Now, can you make a video about women, please?
Thank you for taking time to explain these kinds of things. I like your simple drawings and explanations and the bridging of the gap between the diagram and the physical item. It really fills in the pieces of the puzzle nicely.
I rewatch your videos on motors every once in a while and I take in a little bit more each time. Good stuff to know, I sometimes find myself repairing swamp coolers and air conditioners, and these videos have helped me out with it twice now.
I really like seeing these sorts of videos from you. Its very interesting to see simplified in such a way. With so many people posting novice DIY videos, this is refreshing.
As a refrigeration/hvac mechanic I havent had to get this deep in to motors since my trade school days. I still do love hearing about the theoretical side of things. Thanks for the great video!
Excellent video... I'm a Certified Electronics Technician (CET) so I have a good understanding of electronics... but never really "got" how the motor reversing worked... your video was very clear and easy to follow. Thanks! (I'm passing it along to be used in some training classes,)
Great explanation of the why! I have known the how for 40 years but have never known the why. Thanks for that. It never ceases to amaze me how giant corporations will step over a dollar to save a dime. It would cost next to nothing to add 1 wire pigtail to that motor and make it exactly twice as useful having a dual rotation. I really enjoy all of your videos.
Awesome video. I had been looking for a few hours and everyone had different solutions on how to reversing a split phase motor. You explained in one minute what others tried to explain in confusing and possibly incorrect ways. Worked beautifully, thanks.
Very interesting and perfectly explained. It rekindled my interest in understanding how things work and the underlying principles that govern . It sort of got my starting circuit going! Didn't miss the fact that you used the word condenser on one occasion. Endearing to anyone of my generation. Thank you. Great video!
VERY TO THE POINT, SIMPLISTICALLY BLOCK DIAGRAM PRESENTED ! BRAVO MATE !!! A SIMPLE EXPLANATION , OF A VERY TECHNICALLY COMBINED PROCEDURES FOR REVERSING DIRECTION OF A SINGLE & 3 PHASE MOTOR WIRING, AGAIN SPELLED/OUT SO VERY EASY TO UNDERSTAND THE IF/THAN. A TECHNICAL PROCEDURE-VERY WELL COMPACTED VIDEO, COVERING ALL THE MAIN CAN & CAN'T DOs' . IT IS SO WELL PRESENTED WITH A "HANDS-ON SIMPLISTIC ILLUSTRATION ! AGAIN, BRAVO ! I HAVE SEEN ALL YOUR VIDEOS & COULD NOT DISAGREE ON ANY OF THEM !. IT IS AN ART TO PRESENTING SOMETHING TECHNICAL IN A EASY-PEEZY TO UNDERSTAND PRESENTATION !👊👊💥🎯
Great presentation. I really like how you explain the concepts and accompany that with the disassembled motors and even the oscilloscope. That made it very easy to follow.
I just bought a 3/4 horse induction motor today at a second hand store. The plate didn't say anything about reversing motor, but now I know what to look for. Thanks!
Matthias, I was able to reverse my non-reversible motor (an A.O. Smith, 1/8 horse power) without altering the coils. I simply pulled off the casing ends and flipped the rotor end-for-end. After this, the motor ran in the opposite direction. It may not be possible to do this with all non-reversing motors, but on this one it worked perfectly! The motor powered a heavy-duty orbital buffer that shook so violently that it was nearly impossible to use. I disassembled it, removing the orbital counterweight unit and bolted the buffer disc holder directly to the motor shaft. I thought I had to reverse the motor, which it turned out that I did not have to do, however, curiosity got the better of me and I had to test my theory: that I could just turn the rotor end-for-end to get reverse rotation. It works and was easy to do on this motor. Thanks for your educational videos! Will
you have a lot of induction motors... I think you've been collecting them for more than a few years!!! Great explanation. Especially about why some motors are labelled as non-reversible.
this worked for my rc helicopter. it's very appreciated that people are so willing to share such pertinent information to fix some things. Thank you for making this video
Considering myself highly interested in all kinds of technical stuff, I had to live 67 years until getting such clear explanations. You are a genius AND very gifted teacher! Thanks!
Ramekenas With the use of a homemade inductive pickup, oscilloscopes can be useful in the garage as well. (You really could see whats happening on the spark plug wires) Whats really cool now is that oscilloscopes that used to cost 5-15 thousand dollars (analog) a couple decades ago,can now be had for a couple hundred dollars or less on ebay and craigslist.
Thank you so much for making this very informative and easy to understand (if you're versed in electronics) video. I was looking to see if I could reverse the rotation on my drill press and found this video and it had every piece of information I was looking for. Thanks for taking the time to put it together.
I had the situation at 7:45 with an unmarked motor where I had to disconnect all of the wires, ohm them to see which ones were which and then I was able to confidently unsolder and resolver the switchover, close it back up and low and behold, it worked! Thanks Matthias!
This is awesome... you make it easy to understand. Did not understand 3 phase before from reading the books. Like 90 or 120 degrees out of phase for 3 phase power. Great Job!
Well after watching your video,I needed a piller drill motor reversed, So with help in identifing the starter windings I went a head and went for gold.And YES " YES" It had worked after watching hundreads of videos l still could not work it out,befor watching your stuff. So Thank you for putting this vid up it certainly help me today,
OMG!!!... You've just explained so much in such a short amount of time in three videos, why can't schools do this? I always got the DC bit, forward/reverse/speed, 3 phase I'll never use domestically, so not a big deal, but at least I understand the theory now, but it was always single phase AC motors I didn't quite get because of the way AC alternates, I 'assumed' the AC capacitor was there for a 'kick' but had never bothered to go any further into it because I didn't think I'd ever understand it, but Woohoo!!!... Single phase AC, swapping the capacitor round, changes the rotation, so simple!!!... Why did they never bother to tell me that at school!... A video is worth a entire book!!!... Thank you!!!
Very much appreciate your explanation! I’m a self taught electrician (RU-vid Electrician’ videos ) and have been having a hard time with changing the direction of the motor I need to put on my table saw .
I like your video and your diagrams and explanations very much. They are very informative and probably the best I've seen on youtube. I even checked the videos on reversing a drill press motor cuz apparently some people like to reverse those for special purposes. My dad even put a reversing switch on his bench grinder back in the 40s or 50s.
Matthias - Thanks for a great video and excellent explanations too. I have been reading some of the comments. Interestingly ALL the comments are sensible and appropriate. Very often when someone does a good video, people spoil it with their irrelevant and irreverent comments which is annoying. Kudos to you, and keep up your good work.
Good. I knew all that. I'm heading out to look at a table saw which I'm told two other guys tried and failed to reverse the direction. No history but I am guessing someone bought the wrong motor. It's got two new capacitors. Lol. Your awesome and clear is a great brush up and will save time and make me look like i know what im doing. Thanks. Rich
Very Informative and explained in very clear terms. You present the information at just the right speed keeping my complete attention. Cant stand people who speak way too slow wasting time.
Really interesting. And I agree with below comments. Keep this topic going. I am just coming to understand AC motor and alternator theory of operation. I gain a basic understanding of what is actually happening, when I watch videos such as this, but I don't know enough to have the gut intuition that I have gained with internal combustion engines, which I began learning about as a young boy. I recently bought an older Lima Electric 8KW 12 wire brushless alternator, and since I knew nothing about it, I began to research. The more I found, the more I thought to myself, "Wow, this is amazing!"
Very good explanation. The only thing I disagree with is the comment that the motor at around the 8:30 mark "has to have the coils removed from the motor case or a hole drilled in the case" , to get at the coils common point so it can be split and swapped. As they have to be accessible for the coils to be joined, the common points on these motors are usually buried just under the first layer of coils near the ends of the motor. With a bit of care the wires can be traced back, dug out and split. The process is similar to digging out the common point for 3 phase motors so they can be converted from Y to ∆ connection. I have reversed a number of these motors and always found the common point close to the surface of the coils. I agree that this level of modification is probably beyond a DIY level.
Why so many dislikes? It was a very good explanation of how a motor works. PS Love the "old school" scope. (I started with something similar) Cheers Matthias.
Thanks for the video, it was very helpful. I ordered a brand new motor for my tablesaw from grizzly and missed that the rotation was clockwise and I needed a counterclockwise motor. It was not reversible, but I was able to isolate the start windings and switch the polarity.
At about 9:08 I think you read the motor wrong. I believe the label states Clockwise rather then counter clockwise. I might be confusing some thing though. Really like the video because of the explanation and demonstrations the combo of simple words and simple visuals are a great touch! Matthias you are a great teacher, woodworker, engineer, and many more thanks for your videos
Thank you Matthias, very useful. I like your videos because of the decent quality of sound and vision as well as your clear explanations and diction. Keep them coming!
This is super informative and well presented. Thank you! Now I just need to get my hands on some induction motor...but I don't see any furnace motor on craigslist =(.
You can reverse an AC motor like a pump motor. You just replace the capacitor to a reaktor which is used in fluorescent lamp circuits. And thats it! ;) It is very useful when we have just 3 wires out of the coils.
6:42 thats how you can also use a induction motor as a transformer... ' great vid as always mate. wish i lived somewhere were such motors were readily available (aus, our second hand market for this kind of thing is pretty non-existent.).
