Reversing single phase induction motors

How the starter circuit on single phase induction motors works (capacitor start and resistive start), and how to reverse them.
woodgears.ca/mo...

[@FreemanPascal]

That's one of the best overviews of how AC motors works I've seen. Thanks.

[@jeffcowles8274]

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?

[@lenyfreeman3807]

People who really know their stuff can explain it simply. Those who don't teach in the school system.

[@weedmanwestvancouverbc9266]

The actual quote you want is "Those how CAN, DO. Those who UNDRSTAND, TEACH."@@lenyfreeman3807

[@billkellogg1403]

@@weedmanwestvancouverbc9266 still incorrect... “Those who CAN, do; those who CAN’T teach!”

[@brianlittle717]

This is a great video and you’re the first person I’ve heard who’s gotten this right!!

[@dominikjaremek3120]

Wow, you sir make electrical concepts so easy. I take my hat off to you.

[@TheJSullivan]

This is a really good video have had training on motors in college but it's been a while since I touched one and your video was a great refresher

[@mitchwoodwork]

Nice explanation. reminds me of my university days

[@ccfd1996]

Smartest man in the world!

[@colinprohasky7957]

Excellent presentation!

[@RODALCO2007]

Great informative video.

[@jeffbur2121]

You are really good

[@rustyrepairs2565]

My garage door opener goes forward and reverse. Will the motor spin if I apply voltage to the black wire and the white is neutral. Or do i need the capacitor to make the motor spin in either direction.

[@ToolManTaylor]

Hello Mattias can you tell me if this motor is reversible Can I send you a picture?

[@rotorav8]

Great videos

[@abbtech]

Wonderful explanation.

[@JeremyThompson21]

Whoa...so that explains why i have to periodically blow the dust out of my starter switch to get my table saw running again.

[@eformance]

Couldn't you reverse the motor by adding additional start capacitance, to delay it to 270 degrees?

[@mckenziekeith7434]

eformance you might be able to change the phase shift to 270, but it would require more than adding additional capacitance. A single capacitor can only shift phase by 90 degrees (no matter what the value of the capacitor).

[@iRrrmanion1]

could the "non reversible" motor be reversed by replacing the capacitor with an inductor, thereby changing the lead/lag effect?

[@matthiaswandel]

Richard Manion Not really. The winding already is an inductor.

[@iRrrmanion1]

But by adding a second inductor, the total inductance of the start winding will be greater, which would cause phase displacement. I know there exist inductor start split phase motors, just curious as to whether you could convert a capacitor start to an induction start motor.

[@eglintonflats]

Richard Manion I love how people use argument "don't confuse me with facts, my mind is made up" in their discussions

[@iRrrmanion1]

eglintonflats If my mind was already made up, I wouldn't have asked the question

[@kooldoozer]

+Richard Manion .....Yes, replacing the cap with an inductor will for sure reverse the motor. I have done it and it works.

[@lekhram4549]

very nice 👌

[@mckenziekeith7434]

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!

[@1southsoon]

Hands down this is the best video on KZbin. 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.

[@matthiaswandel]

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!)

[@themaconeau]

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 ;)

[@AsiAzzy]

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.

[@WayneJohnsonZastil]

themaconeau Cause turning washing machine drum need alot more juice than blade maybe?

[@themaconeau]

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 ;)

[@timhyatt9185]

themaconeau would a washing machine motor have enough speed to make a good table saw??

[@one4stevo]

lost me at hello.

[@DIYTyler]

Exciting info and very well explained! Happened to reverse a motor yesterday, was debating if I should make a video....glad I didn't!

[@tiitsaul9036]

extremely well explained

[@JACK-wh6jl]

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 !👊👊💥🎯

[@Wordsnwood]

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.

[@thisisyourcaptainspeaking2259]

So the start winding will likely have higher resistance than the run winding. In fact, the start winding will likely measure open as the start capacitor is charged by an ohmmeters DC potential.

[@chasf9178]

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!

[@juanalvares11]

Very well explained but i have a question i have an ac motor with 5 wires how can i reverse the direction ?

[@nickszabo9669]

How are you able to change the polarity of the winding when you are using alternating current?

[@Askjerry]

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,)

[@user-jh3kz7dp2z]

The evolution of Matthias, Wood to metal

[@brothyr]

LordThanatos666 You don't. It's just welded.

[@brothyr]

LordThanatos666 If you did need to put a bolt through hollow steel/aluminum tubes, you'd drill a hole large enough to fit a wrench to secure the bolt head or nut. Do this where the bolt begins and ends. It's not as strong as welding but it's temporary enough for structures like those used at music events.

[@jhcarr830]

***** According to my goldium and platinium smart watch, you are correct!

[@AbendscheinLGN]

Luk Yat Ming He did get a degree in Mechanical Engineering. :P

[@fussydk]

Great explanation! The thin wire used for the start winding is also to help changing the phase angle due to the greater resistance.

[@peterstewart9376]

Great video, Matthias! I've never really understood stuff like this but this video was really interesting to me for some reason. By the way, you might remember that a few weeks back, I asked you about the difference between a 14" bandsaw with a riser block for 12" of re saw capacity and a 17" bandsaw with 12" of re saw capacity. Well, I just wanted to let you know that I finally saved enough money (I'm 15) for the Grizzly G0513ANV 17" bandsaw. I just placed my order today and am super excited about it! Thank for always sharing your projects, Peter

[@Tony290248]

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.

[@AussieBobL]

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.

[@Ramekenas]

Didn't expect to see an osciloscope in a woodworking shop :D, great video !

[@stevenhardy2898]

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.

[@UpcycleElectronics]

5:30 Did you measure the motor starter circuit waveform with the earth-ground of the CRO connected? I've read everyone's over stressed ramblings about "just buy differential probes." I don't see why people are so scared to just say what works. Darwinian Exit awards are good for the gene pool. My scope has an isolated switching supply, and a plastic case. I think it's completely ridiculous modern scopes are not 100% isolated by default like a DMM. Even without OEM isolation, people should talk about how to make scope measurements and just say, "don't touch the BNC or ground terminal lead." That is more than sufficient warning. Any idiot should know to setup the test equipment, step back, plug in the device, and touch nothing until powering it off. I need to test for voltage spikes on a new Craftsman Jointer, with an universal motor variable speed controller (U2010b). I've reverse engineered (retraced) the circuit, posted on the eevblog forum, and published the board files under public licence. I'm looking for what causes all the failures as seen on Lowe's website reviews. I'm a simple hobbyist with a scope used mostly for hacking uart serial baud rates and Arduino projects, 10 amp AC mains is a bit ambitious. I have a cheap Asian pocket scope ordered but would like to use my Rigol on my test etched prototype now instead of waiting who knows how long for shipping. -Jake

[@aceoft3482]

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.

[@jonathansimms4016]

I have a motor like this on my bandsaw. I want to replace the switch with a magnetic relay switch but the old switch only had one black and one white while I need the two black and two white to hold the magnet together during operation... do you have any experience with this? Where to find the other white and black wire? Thanks a lot. Love your videos.

[@Tuticitis]

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.

[@matthiaswandel]

RoCCaT You could also reverse it if you have two phase power. Just run the starter winding off the opposite phase. But that's equally awkward.

[@Tuticitis]

Matthias Wandel Yeah you are true! There are a lot of ways to reverse. I heared about to use the reaktor and it worked well.

[@DiHandley]

Um...yeah...err. I think I ...er...nope , haven't got a clue!

[@1122lipshitz]

Hello,I've come across your video, and it's just amazing the ability to communicate simply ... Thank you! ... I have a slight problem that I have no idea how to solve it ...I have an asynchronous one-phase asynchronous motor with four wires on one side - red and orange and red and orange on the other. my question is,How to place them on four pins? ...So that I would connect the source of the voltage and the phase.best regardsitamar

[@eiriklade93]

"this motor can't be reversed, because they saved one wire", made me laugh out loud

[@KAFA2020]

Oh beautiful. very good explanation. May you live a long life Full of gladness and health . May all God's blessings descend upon you. May peace be within you may your heart be strong. May you find what you're seeking wherever you roam.?

[@PerisFaidate]

Thats GREAT! I was waiting for this tutorial since the dust collector video! One question: have u ever built a router jig for making wooden marbles?

[@rishanranatunga4851]

Some motors without a centrifugal switch also having a capacitor directly connected to a winding. aren't those called STARTING WINDING and STARTING CAPACITOR ? and how does the capacitor remains without damage due to permanently connection.and how do we identify the windings without a proper color code?

[@MadScientistGuitarLab]

This is exactly what I needed to know and nothing else. I love the hand drawn illustrations! Awesome work and I hope to see more like this.

[@mikelan8921]

Old Matthias is a pretty smart guy, I have an old Logan Lathe w/reversible AC 110v 1 phase motor 1/2 HP which just burned out. Not sure how to fix it except taking it to a motor shop or replacement on Ebay hopefully. Lots of wires, qty 4 going into the motor

[@JamesJames-um5xq]

Hi, have an old bench grinder that ive taken to bits for refurbishing. Its a single phase, start and run type with a centrifugal switch, and does not have a capacitor. There are two wires coming from the windings; a switched (on/off) line, and the neutral, which were connected to the lead. Since taking the bench grinder to bits im not sure of the wires polarity, they are both black. Can I take a guess and connect ? Im thinking that if I get them the wrong way round it will reverse the direction of spin only, so easily remedied ! However I dont want to break something. Can I just connect and see which way the motor turns (50/50) chance of me getting it right, or is it not as simple as this ? Bear in mind this is a start/run type motor, Thanks if you can answer, I realise this is a dated vid.

[@larrypesek3777]

Matthias, love the explanation. I have a 3/4hp boat lift motor that only runs in one direction. It was full of mud daubers, cleaned thoroughly as I thought a switch might be stuck however still only one direction. From your video, I see that windings must be good as it wouldn't run in either direction if windings shorted. Any ideas I'd appreciate. Larry in Florida

[@akfishoner4143]

Hello! I have a 4 pole single phase with no terminals (all wires wrapped into the windings) possible to rewire to go in reverse? When I do switch up the wiring, motor hums until I spin the arbor (start capacitor not kicking things on) and the motor sounds a bit rough. Can’t figure it out :(

[@makeitathome1327]

Im building a electric bike, and i have a question about the rotation of the motor. I've built my diy bike, but the motors spinning the wrong direction. Its a permanant magnet 24v 350w motor. How can I reverse the direction of the motor? I have it hooked up to a 2 pin rocker switch and a 22.2v 1400mah battery and it all works, but how would i have to change it if i wanted to make it go the opposite direction? Its going clockwise now, but i want it to go counter clockwise. If i swap the connectors on the motor ( like connect positive motor wire to negative battery wire and negative motor wire to positive battery wire ), would that work?

[@deweywyatt2875]

A question, i have a 6hp 220 emerson with start and run caps it says on the case ccw rotation. It turns howecer clockwise, 5 wires two on start cap with a bleeder and 3 on run cap. Why is it turning backwards.the compressor was bought new never made air like it shouldi hunted for leaks and everything you can think of. Finally i noticed it was ccw motor and its turning clockwise. Any thing you can think of causing this. There are 5 terminals in the junction. Three are 220 and neutral one jumper sort of in the middle

[@diegomestrecam7674]

grate video!!! Now I understand a bit mor about AC motors!!!! One question. On a single phase motor like the the first schematic that you show, If i wanted to be bidirectional I will Need a Neutral wire and two live wires to select the rotation right? My question is, What happens if I accidentally activate bothe of the Live whires at the same time. meaning that both windings will be runing at the same phase? whill that create som sort os short circuit or burn the motor, or nothin will happen

[@CanadianClassicCarNut]

I use this type of motor to run a pump. I can reverse it by swapping the black and red wires. How would I wire a switch to do this? I have an On-On DPDT switch on hand. Thanks!

[@DF-ee8vt]

It's kind of ironic that the logic of 3-phase motors are much simpler than single-phase motors. To reverse, you just switch any two of the three power supply wires!

[@davidcrawford6505]

I've been Googling, but can't find an answer. Hopefully someone can answer. Can I swap the rotor in an induction motor? Providing that the size of the rotor core is the same. My goal is to get a different length shaft into the motor. I know the bearings may need to changed to accommodate the shaft. Thanks.

[@exoterra5523]

hi, got a Grizzly g1022 motor it says in the manual I need to switch wire number 5 and 8 but can't figure out which are those wires. thanks in advance

[@trapdoorspider9211]

I do like the idea of a dynamo. capacitor’s motors gears controllers. i wonder why they want batteries in electric cars🧐 one would think one could power its self. The techs always been there just suppressed.

[@HoffmanTactical]

Thanks so much for the video! I just converted my "non-reversible" drill press motor with a DPDT switch to reverse. No more backing taps out by hand.

[@SeaWolfe59]

You answered a question I had about my old GE reversible boat davit motors. One of them wont start so i have to give its large pulley a shove to get it going. I plan to first replace the start capacitor. If that doesnt fix it I'll assume its the connections to the start winding or the winding itself. Thanks!

[@arrenbie]

The way you can clarify things is brilliant! You'd make a hell of a teacher!!!

[@DonBrandt]

Thanks for posting this video, i learned a lot!

[@jaydaturkgmailcom]

hello mr Wandel, i have a single phase motor with 4 wires coming out of the motor. The windings are identical. one winding is connected by a capacitor(permanent). Can i just use the other winding and get it going by hand?

[@hambone3145]

I have a Delta Rockwell 12 14 table saw. Is there an easy way to determine if the motor is 3 phase or not? I believe these saws originally were set up for 3 phase but I'm not positive the existing motor is original.

[@ridervectors314]

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.

[@ItsRonsway]

I have a small Logan Lathe and it has a 3/4 hp.motor. I put one of those reversing switches on it an the motor will run in cw or ccw but before it reverses it has to slow way down or when you switch directions it will continue running the same direction. Unlike a 3 phase motor. Is there a way to instantly change directions?

[@matthiaswandel]

ItsRonsway No. You need to wait for the starter winding to re-engage before it can be reversed.

[@ItsRonsway]

Matthias Wandel Thanks that is what I thought. I really enjoy all of your videos, keep them coming. Ronsway

[@alanturner6879]

Hey I was trying to hook a dpdt switch to an old General Electric motor that is used for s disk sander I couldn't figure it out, but I unplugged a wire now I can spin it with my hand to start it either way do you think I can run it like that. Also do you have a video where you install and dpdt switch to reverse a motor whenever you want

[@lcoiro]

I have a split phase 4-pole 240 VAC electric motor and so the spin direction on this can be reversed?

[@richardpatterson4312]

Matthias, You left out nothing is this video, excellent. Now to go cut a hole in my new jet lathe's motor...bummer.

[@kevinmitchell860]

lol what a joke. He should explain how motors with dual paper and oil filled capacitors. there is nothing hard to reversing any motor if you are really knowledgeable in how a motor works.

[@WoodenN8ive36]

I have a motor I would like to reverse.. idk if it can be.. or how to exactly. Any way I can send a pic? Also would you let me know how to..?

[@wisdomwhisper5350]

I have a 1.5 hp ac single phase motor with a start capacitor and 4 wires coming out from the motor. I figured out the leads that goes to the starting winding (checked which ones have continuity to the capacitor wires since the resistance was the same on the 2 windings). If i switch the connections of the starting circuit, the motor just hums and does not turn. Is it because the centrifugal switch and the capacitor are not wired in series as mentionned in your text ? Is there something I can do to reverse the rotation ?

[@1873Winchester]

Very educational, I don't have a lot of experience with 1ph motors since I have no need for them, but very interesting,

[@TheRealRocknRollaTwo]

Well if you can't reverse it isn't that the time to become a little more primitive? Weld the right gear on that motor and now you can make it move any way you like. It would by nice though if the maker whould give you the option to reverse it :p

[@ottard]

Hi, Matthias. At 4:10, did you make a distinciton between condenser and capacitor? I didn't quite understand.

[@demetrijohnsonssirenvideos3590]

Cool, I have a reversible 1/20th horse induction motor from 1949

[@markrenton1093]

I have 110v motor and I would like to change rotation , it has 2 speeds but I cannot seem to find the answer.

[@ytram34]

Why does a squirrel cage air conditioner motor generate more power spinning it clockwise, but less power counter clockwise?

[@jessestrum]

hi matthias, my problem is i want break into the starter winding and extend to a remote reversing switch. cap start induction run motor , i don,t know which terminals to do it from

[@stevev2414]

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.

[@Clerence3]

watched the Video, with your help i could change the direction in less then 2 mintutes thanks from germany

[@danielrperez5778]

Matthias, it's funny a carpenter could make me understand AC motors better than my electrotechnics professor! Many thanks!

[@michaelmckee5736]

I have a Dayton 2 hp trying to hook up to my tire machine For forward and reverse I cannot figure out where to hook the four wires

[@willemkossen]

Now i understand!

[@ivokolarik8290]

What if I drill hole through the outer casing bring the three wires out extend them and bring them back in on the what is essentially the front of the motor then switch the front and back relocating the wiring of the whining?

[@wryanddry2266]

So the size of the phase shift (90 degrees in this case) is determined by the capacitance? So the shift could be something a little different from 90, but close enough? Or is it somehow exactly 90 degrees?

[@matthiaswandel]

its not that simple. Its only approximate, and depends on load. The whole phase shift with a capacitor is a bit of a kludge

[@Temuba]

As always, excellent and very informative. Thank you

[@AvocaSingleTrack]

I have a 220v 1.5Hp single phase induction motor. I would like to slow the initial hard start . Can I do this with an adequately rated resistor and a switch that has the resistor in series with the motor just for the initial start ? Motor says YLJ90L4-19A on the side . Thanks

[@matthiaswandel]

Bad idea. These motors consume crazy amounts of current on start, so you want that done as quick as possible.

[@carlsegan6446]

I typed out a message for advise but I'm not sure you had received it please let me know if you do thanks

[@jimhuggins9589]

A pointless fact for you, this essentially is how a train is detected on the railway with use of a phase sensitive relay. At least in areas with DC traction.

[@sparkyprojects]

When you don't know which is start and run winding, as long as you reverse either with respect to the other, the motor will revers, so you could swap polarity of the run winding also, in a rare selection of motors, a non reversible motor can be reversed if you can swap the rotor and end caps around so essentially the shaft sticks out the other end, can't be done with switch start motors, unless you find a way to extend the contact wires to the other end

[@dodznb238]

Nice diagram explainatoin sir..salamat sir..means thank you sir.

[@oceanviewlaundromat2983]

Would a clothes dryer that reverses during cycle have a have a single phase induction motor or an inverter attached to an inverter duty motor?

[@mobinmk007]

Is the no of turns in starting winding is more than running winding????Starting winding has high resistance and low reactance and running winding has high inductance and low resistance.

[@scotty2307]

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!"

[@Quroxify]

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

[@johnyx7592]

i'm so grateful someone is sharing this kind of information on the internet!

[@aviatrix2]

I enjoy your videos and they are very informative. Could it be that they don't want the motor reversed because instead of the starter switch arm dragging on the pressure collar that it would be pushing toward the pivot point like backing up a trailer behind a vehicle? Would that make it want to break off easier (maybe sooner than later)?