DIY Treadmill Motor Choke Built From a Microwave Transformer

[@aguycalledlucas]

Highly informative video. I was surprised to see how much difference there is between choke vs no choke. Thanks for communicating your findings.

[@dazecars]

Glad it was helpful!

[@bradsmith1046]

Hey just wanted to follow-up and point out how important your videos really are. I asked a few weeks back about winding my own choke, then I came upon a de-funked 12v charger in the back of my shop so I took it apart and realized its transformer was perfect for choke. Then I thought Why bother removing the upper winding as it is not connect in anyway to the bottom. Then I thought to review this video you did again. Lucky me I probably would not have had a chance to thank you otherwise! I cut the top off, pressed out the upper winding and re-welded the frame, all as you suggested. Works a charm as you had said it would. Key take away: Don't be shy to view good "how to" videos multiple times, there is always something new to learn.

[@dazecars]

So glad that you rewatched it and were reminded to remove the other coil as that could have been bad.

[@atmian]

The secondary coil in a 12V charger (assuming regular car battery charger) only holds 12V, so if the ends of that coil are cut off and insulated, I think that should be fairly safe.

[@dazecars]

I still wouldn't risk it

[@danstefanski3471]

I have used your videos to help me with my treadmill motor projects. Now I'm on to making a die choke. Great tips, keep them coming.

[@dazecars]

Glad I could help. Don't hesitate to reach out with any questions.

[@fakeitormakeit83]

These videos you have about these treadmill motors are the absolute hands down best info ive found ! Thank you so much! I have a motor ive been wanting to use but info hard to come by ! Thankyou!

[@dazecars]

Glad you like them! Have fun with your project

[@Richard-gh1gv]

As usual, another fine video that answers the questions we were afraid to ask and does it with great detail.

[@dazecars]

That IMHO is the problem. Questions should always be asked! 😁

[@robertolson6686]

Id just like to add my 2¢ for what its worth. I took a microwave oven transformer whos core is maybe a bit larger than half the size of the ones you demonstrate and instead of just the single primary i stacked 2 primary wraps into it, welded the E n l togethet and it seems to be just as good if not better than the chokes ive salvaged from treadmills. Yes those are made specifically for that motor but lets face facts in that manufacturers dont always put out quality. Ive not seen any rpm or current drop in my machines by doing this peraonally. Anyway just a tip from another diy/fabricator for all of those who look for info. Great channel, great vids, keep up the good work!

[@robertolson6686]

Just to add another note. Your hamd wrapped choke would have preformed much better had you used silicone stranded wire, 12 or 14ga. And had you wrapped the core tightly and without an air gap around the wire. Uses more wire but it does preform decently. I know this because i use a choke (based off of and inspired by your video here) that is 2 mot cores stacked face to face and welded together for my diy welder which puts out 80-100 amp at 32vdc on max setting. The apm depends on what material im welding. 10ga wire soundly wrapped filling the core with no epoxy. Anyway, just a bit more info to help share, keep up the good work!

[@dazecars]

Did you wire the two cores in series or parallel?

[@robertolson6686]

@@dazecars series

[@robertolson6686]

On the same cotr

[@robertolson6686]

Core ... Lol typos

[@randallmarsh446]

thank you very much ..as for DC motors .. I bet this would work as well on A/C motoors as well..brush wise that is. such as in drills and saws ect..?

[@dazecars]

Its my understanding (I am by no means an expert) that it works but not the same frequency range. They are actually opposite. The ferrite doughnut is an effective choke for the AC side so there is not much need to do more plus its in a range that is not as hard on brushes.

[@erikwahlstrom7826]

I have a MC70 controller driving a 2hp motor which am installing on my Lathe. My treadmill did NOT have a choke? Sounds like I should add one for reliability.

[@dazecars]

Can you contact me through my website and send pictures of your board? I have not messed with an mc70 and the internet search I did came up with to many totally different boards all labeled mc70

[@erikwahlstrom7826]

@@dazecars I sent you an email with pictures.

[@dazecars]

I received it, thanks. I will answer here as it may help others. That board likely doesn’t use a choke from the factory as it has other cleaning components on board like the capacitors. I would also observe sparking at the brushes on hard starts. The board likely also has soft start which buy slowly increasing speed instead of trying to immediately ramp up at once reduces but does not fully eliminate the need for a choke. As to your question about the j5 and j4 not having played with an mc70 I have not experimented with the different options and do not know their function. Lots of boards have jumpers like that to test any number of functions specific to their board which are not always drive motor specific. Short of the ability to look at a circuit and determine its function (like an engineer which I am not) you need the pin out sheet. This lays out basic functions of connecting points on the board. Some manufacturers are really good at including such a sheet inside the treadmill and some don’t provide it at all. Let me know if I can be of any further assistance.

[@checopacheco420]

You probably save my life good information tanks 🍀

[@dazecars]

glad I could help!!

[@nickhardiman2142]

Another great video thanks 👍 I've used microwave transformers for other projects before. If your not going to rewind it you can carefully hacksaw through the fine winding and tap it out. Handy if you've not got a grinder or welder. Ps I have both but still used a hack saw just be careful not to cut into the big winding.

[@dazecars]

A wood chisel also works well to cut through the fine coil.

[@frankglass]

You mentioned a hydraulic press for removing the coils. I am looking at a 12 ton from Harbor Freight. Your thoughts if any? Thanks

[@nickhardiman2142]

@@frankglass a 12 ton press would be more than enough to remove the coils. Tapped mine out with a bit of wood and a hammer with no problems.

[@dazecars]

👍

[@moonolyth]

EXCELLENT!! Can you trim off the exes metal on the Microwave part to make it more compact ??

[@dazecars]

Yes you can BUT the core is thin laminated sheets so you need to be carful as you trim. Keep the sheets squeezed together.

[@beautifulsmall]

Very glad I watched this, Ive just put a 1HP 180VDC on a small lathe and can see the clear need for a choke. Very well presented, no oscilloscope needed. Ive also got a unlabled motor that has ~ 3 Ohms winding so 4-5HP ? My initial thought was a 2KW microwave TxF wouldn't be enough but then the primary in the microwave TxF is loaded by the secondary whereas in a choke its just knocking the spikes off so much lower power dissapation. So should be fine. The US transformers will have windings twice as thick as the UK ones of course and need to step up 2x more. Food for thought.

[@dazecars]

Glad it helped!! I thought about buying a cheap oscilloscope specifically for that video but realized the practical observations not only showed the difference clearly but also would be the limit of what most DIYers would have available to them. Never thought about the fact that 220 transformers would have half as many wraps of wire. I have thought about taking two primary coils and wiring them in parallel, and testing effectiveness, and then series and doing the same test. series will double the resistance but might filter better... not sure. At this point I am moving beyond my knowledge base.

[@wantlessobject]

VERY INFORMATIVE! Thanks for sharing this info.

[@dazecars]

Glad it was helpful!

[@terry2346]

Would you recommend both an inductor on the AC side as well as the choke on the DC side?

[@dazecars]

yes, they work differently with different types of current and that results in filtering out different frequencies.

[@devilvortex1]

Instead of using a choke maybe a soft starter with a big resistor that charge the capacitor slowly to prevent inrush current. So you can start the motor even at full power. Sorry for my english.

[@dazecars]

Interesting idea but I have a couple concerns. the resistor would need to be very high wattage and the slow bleed would make the motor take longer to come to a stop when the power is cut.

[@davidpitts9086]

Absolute perfect. A quick question DOORBELL TRANSFORMER, would it work as a DC Choke?

[@dazecars]

depends on the size of the wire in the primary choke. It would probably need to be at least 16 awg, but 14 or 12 would be better.

[@SalvadorMalave-xk9ql]

hi, great video !! do you think it would be a good idea to add a second low voltage winding since there is enough space inside the metal core? The live wire would go through the original, and neutral through the second winding. Also, do you think it would necessitate an air gap?, thank you

[@dazecars]

I thought of trying something similar but it must be only one wire in other words one side of the power flow. You don't want the + and the - both going through a single choke. The one thing I know about chokes is the bigger the better so adding a second coil could improve the function. What I don't know is the best way to wire it. In series it will increase resistance but there will be more coils which should make the magnetic field stronger. In parallel it will cut the resistance in half but I don't know how that would effect the magnetic field. I'm guessing series would be better but until I get an oscilloscope I don't have a goos way to test the options.

[@SalvadorMalave-xk9ql]

@@dazecars thank you , but what if it is for an AC circuit? like in the AC output side of a DC to AC 5kw inverter

[@dazecars]

I would not use this type of choke in that application at all.

[@gregskinner8085]

Hey there. Other than treadmills, what kinds of electronics might have a choke in them. Ive take 3 treadmill apart now and haven't found one yet..

[@dazecars]

As far as I know just treadmills. Chokes are used in lots of things but a basic choke won’t be big enough. It must be a “motor choke”. Those would only be found in things with large DC motors and The only thing I know of that uses a large DC motor is a treadmill.

[@thomastieffenbacherdocsava1549]

You also show a wrapped FT-240-31 Ferrite Toroid Core . Does this work as well?

[@dazecars]

it works on the AC side but is not very effective on the DC side, better than nothing but still not very good.

[@garychaplin9861]

I have the same problem as beautifulsmall, that is 240 V supply in Australia means a lower primary coil winding count. I am wondering if adding a second (or third) coil in parallel would while helping to increase the current flow may have some undesirable effect on the impedance? I would also love to know your thoughts on the ferite ring chokes which I find on some treadmills. Any chance they could work or be modified to filter the power supply? I would also think that an old battery charger transformer primary would also be a possibility and you would not need to strip off the secondary.

[@dazecars]

This is what I know. Two identical coils in parallel will cut the resistance in half which will increase amps/volts available to the motor no problem but it does nothing to increase the effectiveness of the choke. The magnetic field created by the core and the coil is what helps "clean the power" and an electromagnet gets more powerful the more wraps of wire it has (all other things being equal). A better choice would be two coils of equal spec in series. The ferrite ring chokes are good on the AC side of things between the SCR and rectifier.

[@garychaplin9861]

Thanks for the reply, can you please advise what size torroid you use on the AC side, what size wire and how many turns?@@dazecars

[@dazecars]

The torroid is lnked in many of my descriptions and it is 7 wraps per lead @@garychaplin9861

[@WoodenMonkeyKnives]

If you’re running a reverse switch on your motor, should you ideally have 2 motor chokes? One on both leads? Otherwise when you switch direction and the neutral becomes the hot, do you lose the benefit of the choke?

[@dazecars]

So it can be on either side. a lot of the chokes inside treadmills are on the negative side but some are on the positive side. Some setups it works better on one lead over the other so you will want to try it both ways. Once you know which side is best for your application simply put the choke before the switch so it is always on the same side.

[@RelentlessHomesteading]

Choking 101 --- Loved seeing the visual comparison of spark generation - nice work. I'm wondering if some of the people that say their motor dies because it had 'offset' brushes is more because they id not include a choke.

[@dazecars]

I think it is several factors: condition, heat, and lack of a choke. Very few people are buying new treadmill motors and treadmills are something that people use all the time (thousands of hours) or hardly use at all so when you scrap a treadmill you have no way of knowing if that motor has 80% of its life left or only 20%. No choke will shorten the life of the motor either way so if the motor is already on borrowed time it will die that much quicker. One common error I have seen quite a bit is inadequate cooling. The user mounts the motor in such a way that air can not easily be drawn into to it by the cooling fan, or in the case of a fan that is also part of the flywheel they remove the fan all together. Running an SCR without a choke produces more heat which in turn shortens the life of the motor if there is not an effective way to eliminate said heat. And then there is the increased consumption of the brushes and commutator (part the brushes ride on). Most of the sparking IS the consumption of those parts. The brushes are easy enough to replace but adding copper back on to the commutator is a lot harder. Any or all of these factors can shorten the life of the motor but not running a coke only agrivates the issue.

[@Apurak]

thanks for the great content if I want to go with the DIY version of the choke for a 2hp motor, how many loop of wire should I wrap around the core ?

[@dazecars]

Good rule of thumb is the bigger the choke the better so fill it with as many wraps as you can.

[@paradiselost9946]

a ready source is the old high bay HPS lamp ballasts.

[@dazecars]

good tip, thanks

[@Sunshine22232]

You are very good to explain 🤔 thank you 🙏👍

[@dazecars]

You are welcome

[@ahow8017]

If you don’t remove the fine wire coil I wouldn’t say that you are playing with fire but definitely lightning. You would let Zeus loose in the shop and he would be very angry.

[@dazecars]

that is for sure!!

[@VinLie-uf3do]

Thank you for the video, very clear and informative. I wonder if you can tell me the specs on the big choke you use (the one from original treadmill) ? I see the "name plate" specs, but too little/blur to read. Thanks.

[@dazecars]

Its not specs its just a part number The choke in most of my videos is part number 130993.

[@raindeergames6104]

What value choke should I get for like a 2.5Hp treadmill motor? Your videos are extremely informative🎉

[@dazecars]

Not being an electrical engineer I do not have any specs for you, what I can do however is offer you some guidelines. First of all bigger is better. I have several motor chokes ranging from the size of a tennis ball to the size of a soft ball and the bigger they are the better they work. Second the wire for the choke needs to be a minimum of 16 awg. If the wire is not that big or better it will not have the amperage capacity to allow the motor to work properly. Amperage is the most important spec. A lot of the chokes available on line are rated in mA. There are 1000 mA in an amp. Treadmill motors are rated in amps so most chokes available on line are several hundred times too small. Third they are not available on Amazon at least not inexpensively, there are a few privet sellers on Amazon selling used parts for big bucks but the available chokes on amazon are too small because they are not designed for a motor even though they look correct in the picture they are way too small. The choke in most of my videos is part number 130993. Instead of getting one new I would get a used one. A lot of treadmills come with a choke. Go to eBay and search “treadmill motor choke” BUT know that most people on eBay don’t know what they have and the word “transformer" will also appear in most listings. Problem is a choke and a transformer look almost identical so some listings are for transformers and some are fore chokes because the sellers think they are interchangeable. They are not. They would only be interchangeable if you modify a transformer to work as a choke. (as in this DIY choke video) To tell the difference count the wires. A choke will only have 2 wires, a transformer will have 3 or more. Also before I started doing videos chokes on eBay could be had for $25 or less shipped but now that more people are looking for them (due to my videos) the eBay sellers have raised their prices quite a bit. Your best bet might be the DIY option out of a Microwave transformer. Please let me know if I can be of further assistance.

[@raindeergames6104]

@dazecars Thank You so so much for Your effort in replying to my message. It is truly appreciated it. I wish I saw Your videos just 1 week earlier. I threw out a treadmill just last week that had a choke in it. I did not know that I needed it so I only took the motor. I'm going to use it for a small surface grinder spindle motor that I want to build from one of my small desktop milling machines. Thank You sir.

[@dazecars]

I too will be making a surface grinder

[@stephendawg1]

Thanks for the good info!

[@dazecars]

Glad it was helpful!

[@bostedtap8399]

Excellent work, great visual demonstration of what 100 Hz or 120 Hz does to a brushed DC motor. Do you have any experience on using a DC capacitor across the motor supply may I ask? Thanks for sharing. Regards John.

[@dazecars]

I have played with an RC circuit (capacitor and resistor in parallel) had one on my lathe for a while and it had an observable effect by it self but not much different than the choke and not any observable improvement when using both. The reason I removed it is if I loaded the motor in other words put it is a situation where I was pushing up against the max available torque the RC circuit caused surging. Could be because the cap was incorrectly sized but I don't know.

[@bostedtap8399]

@@dazecars Hi, thanks for replying. I got both a choke and a large (Physical size cap diameter 2.5" x 5" tall, I cant find both items at the moment, Grrrrr!) with an eBay purchase, but thought the inrush would be too high in operation. I have another ex treadmill motor that I want to set-up and sell with a rudimentary system, hence interest. Again may thanks for the information and great videos. Regards John from the UK

[@dazecars]

@@bostedtap8399 Glad I could help, don't hesitate to reach out if I can be of further assistance.

[@champspec]

I was thinking the same thing… @Daze, your knowledge and understanding of circuits is impressive for not being being in the field professionally. I think adding a start capacitor is necessary with any DC motor circuit for motor longevity. Thats why you see many motors with caps mounted directly to the bodies. Check out Jeremy Fielding’s channel if you haven’t. He has some good content that you’d be interested in.

[@dazecars]

👍

[@Z-Ack]

You can literally measure the coils henrys for 20$ if you buy a transistor tester.. drok makes a good one. Theyre the testers that can test everything, component testers.. they got a little lcd display and an atmega chipset as the mc. Theyre great at compinent level. Will give you the esr and all for caps, identify good and bad mosfetts or transustors, tests diodes with leakage. Tests inductors like the chokes you made here.. theyre pretty accurate also.. cheap too..

[@dazecars]

Thanks for the tip!!!

[@markhedquist9597]

Excellent! No other channel I've seen has this info. Very glad I stumbled on your channel!

[@dazecars]

Welcome to the party!

[@samehdarawshi3537]

great video. much appreciated.

[@dazecars]

Glad you enjoyed it!

[@Faysalariss]

I finally got a transformer, I cut it, took out the fine wire and then tested it on the motor. I didn't see any difference in sparks so I took off the top and tested for a magnetic field, but there was nothing there. I haven't damaged the wired, I get a continuous path of 0.76 ohm. I'm really not sure where I went wrong do you have any suggestions? Every step in getting the other parts or making them work has had a problem, but at least it was relatively obvious what the solution was I think I might just run without it cause I really just can't with this anymore, I don't have time but do have extra motors.

[@dazecars]

If its not making a magnetic field there is likely a short in the coil.

[@stevenjozefik659]

Love your work , I don't mean to get nerdy , but the treadmill choke is specked at a certain inductance for that circuit . Measured in henries in fact . An o scope shows ripple , which is the nerdspeak for dirty electricity. In an audio circuit you can actually hear a nasty buzz .

[@dazecars]

Thanks for the comment and I'm glad you like my channel. I like nerdy and I was aware of henries. The problem is once we ditch the treadmill board and go with the SCR and or change out a motor a whole new list of variables that we don't have the technical data on eliminate the ability to calculate the "correct" size. Even if I had those specs the calculations are above my pay grade 😂. The good news is all these "motor chokes" have similar specifications with the one constant I have found that the bigger they are the better they work. The other thing is a choke on a motor is only there to prolong the life of the brushes and commutator so as long as you are in the range they will all work about the same. Where henries really make a difference is like where you said audio circuits and other sensitive electronics where you are trying to filter out a very specific noise range but on a motor all you are trying to do is smooth out the power. That is why just about any coil on a core will have some effect.

[@Boudreaux911]

I have a question my treadmill doesn’t have a motor choke. Is there a reason why? Thanks for sharing video!

[@dazecars]

Your treadmill likely uses a PWM which produces cleaner power so the choke is not required. Not a bad idea but not required

[@Boudreaux911]

Thanks for getting back with me! I enjoy the channel!👍

[@dazecars]

glad you like it

[@nativetp]

Thanks for all your videos! Would it be possible to connect the upper coil to the lower coil so they create one big loop? Thanks!!!

[@dazecars]

no because the fine wire coil can not handle the amps. The wire is too fine

[@nativetp]

I see your discussion below. Thanks for the clarity.

[@nativetp]

Great, I saw the conversation. Thanks so much!

[@dazecars]

👍

[@bradsmith1046]

Thanks for the rundown on motor choke options. Just wondering, I see many videos of people rewinding rotors and even stators in very crude work environments. This then leads me to wonder if instead of just wrapping insulated stranded wire on you diy choke you might use some insulation paper and wrap bare stranded wire on the former microwave transformer? Incorporating a crude fishing reel style wrapper it might only take a minute or two to create the stranded wire wrap which could then be shellacked.

[@dazecars]

you could use actual wrapping wire like they use on motors and such as long as it is a heavy enough gauge. Keep in mind it is not "bare". Bare wire does not create the wrapping effect, the current just jumps from wire to wire and takes the path of least resistance. Actual winding wire has a thin clear insulative coating on it.

[@Techbymas]

Can I use 220v to 12v step down transformer primary coil as a choke? , Plz reply as soon as possible

[@dazecars]

depends on the diameter of the wire in the coil. Needs to be at least .05" or 16 awg

[@carlkellogg5342]

Hi, great video's. Question ? How do you select the right size of choke for a treadmill motor ? Thank you.....

[@dazecars]

The most important factor is the size of the wire in the coil, needs to be at least 16 awg. Also I have found that the bigger the choke (size wise) the better it works. Im guessing that is because the wire is bigger, the ferrite core is bigger, and so the magnetic field is also bigger. The one in most of my videos is about the size of a tennis ball but the better one on my lithe is closer to the size of a softball. The choke in most of my videos is part number 130993. Instead of getting one new I would get a used one. A lot of treadmills come with a choke. Go to eBay and search “treadmill motor choke” BUT know that most people on eBay don’t know what they have and the word transformer will also appear in most listings. Problem is a choke and a transformer look almost identical so some listings are for transformers and some are fore chokes because the sellers think they are interchangeable. They are not. They would only be interchangeable if you modify a transformer to work as a choke like in this video. To tell the difference between a choke and transformer count the wires. A choke will only have 2, a transformer will have 3 or more. Please let me know if I can be of further assistance.

[@carlkellogg5342]

@@dazecars Again, thank you for taking the time to respond. I still think you have the best Threadmill video's information on KZbin. P.S I have found a couple 130993 chokes in ProForm treadmills.

[@dazecars]

👍

[@ezramel]

good info but is the choke in line with the hot wire or inline with the return wire?

[@dazecars]

I put it in line with the hot side but it will also work on the negative side. I have seen it wired both ways in a treadmill.

[@byranyates6987]

The transformer choke is 5.5 mH . Is there any other spec such amp rating (suspect it is rated at 20 amp) maybe resistance and weight ? Might be able to match at electronics sites such as Mouser or even compare values of other recyclable electronics.

[@dazecars]

Ether it is a transformer or it's a choke. There is no such thing as a " transformer choke". Sellers on places like eBay and other privet seller listing places will list them as both because a transformer and choke look very similar and they don't know the difference. Lots of people have tried to find them on places like Mouser and those are all component size. Simple answer is if it's not labeled AS a MOTOR choke than its not going to be big enough.

[@byranyates6987]

@@dazecars I understand the difference, should have used the correct term. The correct wordage would be power inductor filter (choke). Although this choke is in the form of a transformer. The form size depends on how much ( power )amperage, wire and core. I was trying to get some spec as to what could be compared rather than just looking for arcing when running it. If the modified microwave wires were maybe measured for resistance or Henry’s ?

[@dazecars]

Not being an electrical engineer I do not have any specs or calculations for you on the motor choke. What I can do however is offer you some guidelines. First of all bigger is better. I have several motor chokes ranging from the size of a tennis ball to the size of a soft ball and the bigger they are the better they work. Second the wire for the choke needs to be a minimum of 16 awg. If the wire is not that big or better it will not have the amperage capacity to allow the motor to work properly. Amperage is the most important spec. A lot of the chokes available online are rated in mA. there are 1000 mA in an amp. Treadmill motors are rated in amps so most chokes available online are several hundred times too small. Third they are not available on Amazon at least not inexpensively, there are a few privet sellers on Amazon selling used parts for big bucks but the available chokes on amazon are too small because they are not designed for a motor even though they look correct in the picture they are WAY too small. The choke in most of my videos is part number 130993. Please let me know if I can be of further assistance.@@byranyates6987

[@eCitizen1]

I'm just curious about how effective 2 microwave primaries would be compared to just one.

[@dazecars]

I honesly don't know

[@JohnKennedy-yg3ks]

Can you give the part # and source for the commercial choke used in the video which gives the best performance?

[@dazecars]

The choke in most of my videos is part number 130993. Instead of getting one new I would get a used one. A lot of treadmills come with a choke. Go to eBay and search “treadmill motor choke” BUT know that most people on eBay don’t know what they have and the word transformer will also appear in most listings. Problem is a choke and a transformer look almost identical so some listings are for transformers and some are fore chokes because the sellers think they are interchangeable. They are not. They would only be interchangeable if you modify a transformer to work as a choke. To tell the difference count the wires. A choke will only have 2, a transformer will have 3 or more. Generl rule of thumb is the bigger they are the better they work, also the coil needs to be at least 16 awg. Please let me know if I can be of further assistance.

[@lanarkwanderer]

Did you try combining the choke with a large electrolytic capacitor ? Most DC full wave rectifiers use a pi filter with two capacitors across the output terminals and a choke between them. A low pass filter. This should smooth out the ripple in the 120 hz power and suppress and sparks.

[@dazecars]

This is one of the most common comments. People ask or comment all the time about adding a capacitor. I did run one for a wile. It came directly from a treadmill board. I removed it because it caused surging under a load and there was no visual difference in brush sparking.

[@lukehanlon9965]

Really good! Thanks Bro

[@dazecars]

No problem!

[@joehugo5134]

Allways appreciate your vids! Learned a lot. Question; tje sparking, does it ruin the motor (burn), or deplete the brushes?

[@dazecars]

yes. 😂😁 inside the motor is a copper strip called a commutator. The commutator is what the brushes ride on and the system is designed with the brushes being the softer materail so as to minimize the wear on the commutator but even with the brushes being softer the coper depletes over time. The sparking you see is similar to putting a piece of steel up against a grinding wheels. The brush material and copper being depleted sparks as it burns up as well as electrical arcing. The brushes will still wear faster and can be replaced BUT the copper is not easily replaceable so if it is depleted the motor will need to be replaced. Controlling a motor with an SCR and not using a choke will depleat both the brushes and the commutator.

[@joehugo5134]

@@dazecars Thanx for the reply. Makes sense.!

[@dazecars]

👍

[@paulmanhart4481]

Hey, it’s me again with some questions. I got two different toroid rings. 1. Hondark 49 x 32 x 15 ferrite core MnZn PC40 (Amazon) 2. Mag FT-140-43 toroid core. I’m not sure how to choose one for this application. I also have the SRC 120 240 vac 10000 Watt , the Boamain 100 Amp, 1200 volt diode bridge rectifier and a big DC choke. I also got the digital rpm display you used. So, I’m ready to go, I think. My question is about the toroid. How does one calculate the correct toroid material and dimensions? How many wraps of each wire and in what direction? Is one clockwise and the other counter clockwise, or both counter clockwise? I’m not putting you on the spot here for blame if something goes wrong, but I just want to know what you did and how you figured it our. I’ve watched KZbin videos on toroid ferrites and it’s not clear to me. There seems to be two different patterns. Basically, I’m not as smart as you. I am an optical physicist but know nothing about electric circuits. Thanks again for your assistance. Paul.

[@dazecars]

This is the one I would use. It's a good size. I do 7 wraps, in opposite directions. I don't think it matters but that is how the ones from treadmills have come to me amzn.to/3V3TQyl

[@carlkellogg5342]

Hi. Have you ever see a capacitor in line with the motor at the dc out in place of a choke ?

[@dazecars]

My experience with capacitors is they cause surging when the motor is under a load.

[@victorrivera5445]

Your videos are the most comprehensive and accurate on KZbin!. I have a large amount of 1" steel square bar and I'm considering welding my own choke frame from this material. I would cut and then weld the bar stock into a 4 inch tall "W" pattern similar to the frame of a manufactured choke. Following your advise that "bigger is better", I would then wind 4 or 5 layers of 14 gauge insulated, stranded wire on the frame capped by a spot welded plate. Based on your experience, do you think this would work?

[@dazecars]

I don't know how well that would work. Might work very well, but also might be an epic fail. Transformers and chokes use a laminated core to eliminate eddy currents in the material. Super important on a transformer but I don't know how important it would be on a choke. Your winding need to be as uniform as possible and once it is done the coil needs to be locked into place via epoxy or other material wedged between the coils and the body. Failure to do this will result in humming. I would love to see pix of your choke build and hear how it works out. may be easier if you contacted me through my website.

[@jakeknight6154]

Would an emi filter serve the same purpose as the motor choke?

[@dazecars]

I am not sure about its effectiveness but my concern would be amperage load. A treadmill motor draws in the range of 15amps most EMI filters are quite a bit less than that.

[@jakeknight6154]

@@dazecars fair enough, thank you. I found one rated for 30 A, pretty inexpensive. Worth a shot. I’m building the controls to throw a treadmill motor on the mini lathe. I’ll keep the community posted.

[@dazecars]

@@jakeknight6154 30 amps should be more then enough

[@mr.makeit4037]

Just wondering. Could you, after Removing the output windings in a microwave diy choke, cut the metal thickness down to the thickness of the input windings, reweld the mounting plate? Would this improve performance?

[@dazecars]

I would assume that it would improve performance but have not tested it. If you do that keep in mind that the core is laminated and would need to be compressed while cutting or milling to keep the outer layers from "fraying"

[@mr.makeit4037]

@@dazecars with fraying in mind, how would you cut this? Would this inspire a future video for testing? Maybe a diy coil could be perfected to be able to highly recommend. Keep up the good work.

[@dazecars]

sacrificial aluminum clamped to either side the keep it all tight as you cut it and then mill it flat

[@123suzukisamurai]

Wow. Thanks for this

[@dazecars]

My pleasure!

[@836dmar]

Very good info without too much tech talk nor too much simplification.

[@dazecars]

That is the tightrope I try to walk

[@williamnicklaus2203]

There are two coils in the transformer, would there be a difference if you USED the other half of the transformer coils as a choke? Could you just cut out the un-necesary coils rather than cut/re-weld the core? Thanks, Bill

[@dazecars]

You can not use the fine wire coil as it will not handle the amps. yes you could cut said fine wire coil out as long as you don't damage the primary winding

[@jackwilson1245]

Question not related to this video. How do you attach the wires to the better quality rectifier. Soldering, special connecter or modify the unit to fit a standard connector. Thanks.

[@dazecars]

I have done two of the three things you mentioned. The first one I put together I reduced the width of the terminals and then opened the connectors with a screw driver to accommodate the extra thickness. Worked well no issues. All subsequent ones I soldered wires to the terminals and then covered the terminals with heat shrink tubing. Worked equally as well but does not have the risk of coming loose or the risk of something shorting out the bare terminals so that is IMHO the better way to do it BUT a soldering iron will not get the job done. I use a torch and I attach a pare of vice grips to the terminal near the base where it enters the body of the rectifier. This helps protect the rectifier from heat. I then heat the tip of the terminal with the torch and apply solder to the connection.

[@jackwilson1245]

@@dazecars Thank you.

[@dazecars]

👍

[@tewitt1949]

How is the choke wired into the system?

[@dazecars]

Check out my SCR video there are schematics.

[@rayg436]

would using a large capacitor across the d c leads between the chock and the motor protect the motor further?

[@dazecars]

I have played with an RC circuit (capacitor and resistor in parallel) had one on my lathe for a while and it had an observable effect by it self but not much different than the choke and not any observable improvement when using both. The reason I removed it is if I loaded the motor in other words put it is a situation where I was pushing up against the max available torque the RC circuit caused surging. Could be because the cap was incorrectly sized but I don't know.

[@rayg436]

@@dazecars yes I would think that you had the wrong capacitor for the power draw on full load . thanks for the fast reply

[@dazecars]

@@rayg436 The RC circuit I was using was cut from a defunct MC-2100 so you would think it would be close being that it was designed for a treadmill motor but apparently not close enough. 😁

[@rayg436]

the load of a treadmill peaks only when you put your foot down its not continuous like a tool

[@dazecars]

true

[@lafarms]

I just know this is answered elsewhere on here, but have not found it yet. Where can a person find a choke? I have been tearing apart all sorts of amplifiers and things that plug in. I don't think that I could build a good enough one myself. thank you. David

[@dazecars]

To get a "motor choke" you need to scrap somthing with a motor. The choke in most of my videos is part number 130993. Instead of getting one new I would get a used one. A lot of treadmills come with a choke. Go to eBay and search “treadmill motor choke” BUT know that most people on eBay don’t know what they have and the word “transformer" will also appear in most listings. Problem is a choke and a transformer look almost identical so some listings are for transformers and some are fore chokes because the sellers think they are interchangeable. They are not. To tell the difference count the wires. A choke will only have 2, a transformer will have 3 or more. General rule of thumb is the bigger they are (physical size) the better they work, also the coil needs to be at least 16 awg. Please let me know if I can be of further assistance.

[@lafarms]

@@dazecars Thank you, I will go Treadmill hunting. I have a half dozen motors but did not save anything else from those. My bad! I was using a wall dimmer switch and a capacitor. worked... until it didn't!

[@dazecars]

👍

[@stefan3832ify]

My comments keep getting kick out or just not going through for some reason. Maybe because I've tried attaching a link of a chock I purchased on Amazon. Filter Choke - Value: 7.0H, DC mA: 50, DC RES: 550 By Electronix Express. I've taken the link off to see if it helps . My question is Do you think this choke will work or is it too small for a set up similar to your video (Hooking up quality components to SCR controller) ? I hope this message goes through and there is enough information of the choke for you to tell. The tredmill I took apart didn't have a choke as could tell only a small transformer that would probably be even smaller than the one I bought after removing half of the windings. Thanks for your videos

[@dazecars]

That is way small. It is raited at 50ma or .050 amps so roughly 360 times to small

[@joearcher7188]

WONDERFUL, you just helped me out in my plans. How about using two of those 110 volt microwave coils in series? If you could test that and see how much rpm was lost we would know if it was worth while. Thanks again.

[@dazecars]

Hardest part would be getting two identical transformers. I scrapped 11 microwaves trying to get two matched ones to make a magnetic base. Finally got two that were close but none were identical. Adding a second coil in series adds a lot of wire and is going to reduce your amp flow. A better option might be to wire the two coils in parallel. That would cut the resistance in half BUT I am not sure how it will effect the magnetic field or its ability to act as a choke... something to think about.

[@robertolson6686]

You dont really need 2 primaries from 2 "identical" transformers. While it may seem ideal 2 closely shaped cores with the same sized cross section have very similar if not identical primaries since to build them to 120vac they basically use the same size wire and # or wraps. But even still a primary rated for 120vac usage of any wrap can work just fine as long as it fits inside the core lol. I use a few now. Just make sure you wire them in series

[@dazecars]

👍

[@NefariousMinds]

I am seeking some help finding an economical motor for my context. Really, it just needs to be able to run btwn 300 and 400rpm for about an hour or two without overheating. I'm guessing that I would only need around 1.5ft/lbs of torque. I also need it to be fairly quiet. I have spent countless hours searching online, and what a rabbit hole that is! The motor is either to big or too small or too expensive. Any help is appreciated!

[@dazecars]

Seldom if ever will you find a motor that will be perfect for any given application. If set up correctly it sounds like a treadmill motor would fit the bill. A treadmill motor is happiest above 1000 RPMs for long periods of time as that moves enough air to keep it cool. Then if you gear it at 3:1 you will have the speeds you are wanting. If you don't want variable speed you could replace the potentiometer in an SCR with a fixed resistor of the correct resistance for the speed you want it set at.

[@NefariousMinds]

@@dazecars I am currently running a 6500 rpm treadmill motor. The brushes are chipped and worn and has a constant arch. After about 20 min or so the motor gets extremely hot. I went to a local motor repair shop, and they told me that running at low rpms would cause the motor to get that hot. Right now the motor is exposed, but I would like it to be mounted inside. With it getting that hot, there is no way I'm doing that So, it sounds like I should replace the brushes, hook up a choke, and gear it down. 3 questions: How do I get the right brushes? How do I know that I have the correct choke for my motor? What is the best way I can gear it down?

[@NefariousMinds]

@@dazecars I was not only interested in doing this project for my own machine. I wanted to make more of them after I completed my prototype. The treadmill motor is not economical. I was hoping to find the correct motor, new, for somewhere near $100.

[@dazecars]

@@NefariousMinds If you don't have a choke on it that will also lead to excessive heat and is actually the bigger part of your problem. Not saying the motor shop was wrong but their answer is motors in general. Treadmill motors are designed to run at lower RPMs for extended periods of time (low RPMs being relative) 1. To replace the brushes you find one that is the same size and shape. My local hardware store as a brush assortment. 2. Chokes are simple my observation has been the bigger the choke the better it works. 3. Pulleys are the best way to gear it down. A 1" motor pulley and a 3" pulley for the rotating assembly will give you 3:1

[@dazecars]

@@NefariousMinds With gearing you have a lot more options as gear ratio reduces RPM and increases torque. If you took an AC motor with .5 foot pounds and 1000 RPMs operating speed and gear it at 3:1 you will get 1.5 foot pounds and 333 RPMS

[@derekdeveau2708]

Great video as always. Question...if you took the transformer, connected the two coils in series, making on coil, all be it in two parts with different size wire in each coil, would that enhance the effect as a coil as a choke and eliminate the danger issue of using the smaller wire coil?

[@dazecars]

won't work. The fine wire of the second coil will at the least restrict power flow so much that your motor will loose speed and torque but more likely you will burn through the wire somewhere as it is way to fine to handle the loads these motors will put on it. Wire size is directly proportional to the amps that wire can handle.

[@derekdeveau2708]

That makes sense...what if I took the large coil out of two transformers and installed them both Into one choke, hooked up in series? Do you think that would improve the performance of the diy choke?

[@dazecars]

​@@derekdeveau2708 First the problem with that is the coil adds resistance (this is the reduction in RPMS I mentioned in the video) and a second coil in series will add more resistance. Second a better option would probably be to cut down the body size so that it perfectly fits one coil (that will be a future video) Just guessing it will work better but it is at least an educated guess 😂. And third we are chasing diminishing returns. The transformer coil choke was almost as good as the factory built choke in spark reduction so any further improvements will have large costs in materials/effort/time for little to no gains.

[@derekdeveau2708]

Makes sense. Appreciate your input. Thanks.

[@dazecars]

@@derekdeveau2708 glad I could help

[@gatovich27]

Your video is very helpful. And I'm doing DIY project using ex treadmill motor. But, since it's hard to get motor choke in my country (Indonesia), I'm planning to make it myself. Can you help me with informations about the motor choke you use? I really need to know the approximately size of the coil core (length & wide), the wire diameter, and maybe if you don't mind the code of the motor choke, so I may find the datasheet online. Thanks. I really appreciate it if you could help.🙏🏼🙏🏼🙏🏼

[@dazecars]

sorry it took me so long. looks like 18 awg and the actual core is a little bigger than 1" X 1" X 1"

[@gatovich27]

Ok... Thanks for the info. It's very helpful

[@dazecars]

👍

[@daxliniere]

You mentioned the cut transformer would need to be welded back together. If people don't have access to a welder, they could also create a pair of custom plates and use to bolt the two halves together.

[@dazecars]

great idea. There are lots of different ways to get it done.

[@Z-Ack]

To stop chatter you really need to weld but you can superglue all the loose plates together then clamp it as tight as you csn get it with superglue then use jb weld to make sure it stays secure.. if you dont glue it the force of whatever clamps youre using wont evenly press against every plate which will chatter when energized.. so glue to fill all the small voids to be sure you wont be leaking out a butt ton of eddie currents from the loose plates..

[@johndooley8837]

Dollar store epoxy should be fine

[@dazecars]

👍

[@davidhayes6639]

Thanks!

[@dazecars]

Glad I could help, and thank you!

[@carl112466]

The problem with the blue wire choke is not all the wire fault. The core of the iron is reaching saturation. If you leave a gap between one side of the top plate.

[@dazecars]

thanks for the info

[@eCitizen1]

When you are modifying the microwave transformer, you can avoid taking the core apart by using a hacksaw to cut down one side of the secondary and punch the remains through. This negates the need to weld it back together afterwards.

[@dazecars]

yes that is an option, but it is not the best option. The core is glued together and in the process of pressing out the core you don't want there is a higher risk of damaging the core you do want.

[@eCitizen1]

@@dazecars I've had great luck doing it that way. I also use very heavy gauge wire with thick insulation, so I haven't had a noise/vibration problem.

[@dazecars]

@@eCitizen1 👍

[@daxliniere]

If you have two identical microwave transformers, you could put two of the primary windings onto one coil former and wire them in series.

[@dazecars]

That would double the resistance. Parallel might be a better option because (just brainstorming) it would be able to cary more amps and have half the resistance BUT not having actually done it I have no idea how the dual could setup would effect the magnetic field and how that dual coil field would effect its ability to function as a choke. Dual coils in series would for sure work other than the small percent amperage loss.

[@robertolson6686]

Afterbfindingbthis great video and commenting on some others i tried using 2 120vac primaries from 2 seperat mots on one mot core. I did not measure resistance nor voltage but did measure rpm of motor and workpiece! I lost no rpm and my motor is preforming better than it ever had before. I have a choke from a treadmill on another machine along with an mc 2100 but there is no way to compare without extensive swapping of peices as my diy choke is run off an scr. Imo tho it has to be on par just judging by the preformance. So again thanks for all the great info. Love this channel

[@dazecars]

👍

[@stevebryson4414]

Wondering if choke from a tube amplifier work.

[@dazecars]

no wires are too small

[@stevebryson4414]

Hope to use 4.25 hp 24.4 amp 5195 rpm motor for wood lathe, going SCR like you suggest, finding choke is the problem. Bigger the motor bigger the choke needed, hold true? I don't want to be dismantling an old tm only to find choke is not ideal. Will a 130993 work with my motor? Your clips are so well done, become so popular, finding them is a challenge. Really enjoy the clips. Thanks Steve

[@dazecars]

Thats a fantastic motor!! Amps will be your issue and the wire size on the choke has a direct relation to amps. yes bigger is better but good news is its an easy fix, if you take two identical smaller chokes and put them in parallel you double the amperage capacity.

[@stevebryson4414]

2 of them $90 and 5 hr drive 😢

[@dazecars]

They were a lot easier to find beofre I started doing videos.

[@dmw_cutlery]

What kind of choke it take to make a motor work???

[@dazecars]

the motor will work without the choke, the choke is there to help the motor run better and last longer

[@dmw_cutlery]

Yes i know but i want to buy one....and i realy dont know what kind to buy....i dont want a used one for ebay i want a brand New one

[@dazecars]

@@dmw_cutlery it is not something that usually goes bad so there isn't much difference between new and used. With that said the choke in most of my videos is part number 130993

[@dmw_cutlery]

Thanks my friend i will look for this🙂

[@dazecars]

👍

[@dizzolve]

what exactly is sparking

[@dazecars]

The brushes and the commutator (copper part the brushes ride on) every spark is a little bit of the material from both parts burning off

[@techyash7192]

how much turn do i have to wind

[@dazecars]

Good rule of thumb is the bigger the choke the better so fill it with as many wraps as you can.

[@hamzehmomani6682]

I was watching a video from a you tuber channel called schematics on chokes. He was mentioning that the choke will produce nasty flyback if not used in conjunction with a flyback diode and capacitors. I wonder if you have any idea about that. Nevertheless your work is great and appreciated.

[@dazecars]

Issues with needing a flyback diode on chokes are usually in components where noise is an issue (more sophisticated electronics). In the case of a motor choke you can not use a flyback diode because when the motor is turned off it will be free spinning, producing voltage in the opposite direction, at that point it becomes a generator, and the flyback diode will be creating a direct short across the leads of the generator. This has the positive effect of acting as a brake on the motor but there will be electrical arching at the brushes which can damage them and at the very least shorten their life. I film said flash in this video kzbin.info/www/bejne/aKGWXqaLj5mJhqc The other thing is a lot of older treadmills came with chokes and never once have I found one with a flyback diode. Engineers who have a bunch more education than I do designed those systems and never installed a flyback diode. 😁 In theory it seams like a good ida but in reality is not.

[@hamzehmomani6682]

@@dazecars well. That could be true. But as we are all sharing ideas I thought it would be a good idea to highlight it. The thing I truly raise my hat for is your attention and prompt response to viewers. Stay safe and keep the good work.

[@dazecars]

​@@hamzehmomani6682 Thanks for the comment! As I have said is many of my videos I am an electronics hobbyist not an engineer so there are lots of things I don't know and am always looking to learn. Flyback diodes can be important components in a lot of applications especially those with sensitive components where noise is an issue. I use them in my automotive projects when hooking up a radiator electric fan. When shut off the fan acts as a generator and that can cause arching inside the relay shortening the relays life. The diode bleeds off that charge. You are the second person to contact me about a flyback diode in the last couple of weeks. Makes sense because as I said before it is a good idea in theory not taking into account the massive volts and amps created by a free spinning treadmill motor. My channel is viewer driven so it looks like I need to make a video about flyback diodes. Thanks for the idea. At this point my channel is small enough that I can still manage to respond to every comment. I hope as the channel grows I will continue to be able to do that. Thanks again for your comments!

[@TheIntermont]

You wouldn’t need to remove the secondary winding from the microwave oven transformer if you put a jumper across the secondary terminals shorting them together.

[@dazecars]

I don't think I would risk it. I don't know how that second coil would effect the "choking properties" of the assembly.

[@petersack5074]

Hi. I use an angle grinder, and cut off each coil wrap, then knock them out, with railroad spike; with sharp end, cut off. Grind throu those welds, also if necessary. Winding #12 gauge wire, onto secondary, makes for a good DC charger. (rougly about .8 volt, per turn.)) BUT, remember, microwaves are designed, to be run UNDER LOAD, CONSTANTLY; which is why, there are not too many windings, on the primary. Only good, for about 10 minutes, on; on a battery charger i created. ( Gets very warm ) Good luck all !

[@dazecars]

Thanks again for the good info!!

[@robertolson6686]

They do get warm, luckily we can set up fans for cooling lol.

[@dazecars]

👍

[@a.joegevara3519]

I built a choke out of a transformer to smooth out the current when I converted my Lincoln tombstone from AC only to AC/DC.

[@dazecars]

How did it work?

[@a.joegevara3519]

@@dazecars It smoothed out the DC current. I built a 250A bridge rectifier to convert it, I used a much larger transformer with a very large gauge wire for my application. And then I went a little overboard with Dinse twist-lock lead connectors, 120v outlets and a 24v power supply to power the fan in my helmet. leads

[@dazecars]

👍

[@213BRANDONP]

Moral of the story dont run a current limited circuit without limiting the current otherwise said circuit will convince your commutator to lose weight

[@dazecars]

well said!!

[@paulmanhart4481]

Are you a surgeon? Just curious. Clean hands. 😬

[@dazecars]

Sometimes they are clean, sometimes they are dirty, just depends on the project and when I shoot the video 😂

[@Nourrights_psalm118.8]

You ment to say silicon iron core not ferrite

[@dazecars]

Thanks for the clarification