All About Converting Stepper Motors To Generators

[Music] all right so we've been looking at our generation actually alternative ways of generating and how we can actually link things up like wave power water power gravity loads of ways and we've been doing it from scavenging bits and pieces that we can find around us and that's kind of awesome because you learn a lot and you learn an awful lot about motors now there are basically two kinds of motors ones with magnets in them and ones without magnets in them the easiest one to use are going to be the ones with magnets you have to do the least work on those if you're using ones without magnets you've got to do something to magnetize it or there's some residual magnetism you can use so we've been looking at a whole range and if you're interested in that have a look at some of the videos that have done on adapting motors on this one we're going to talk about a specific kind of motor and the reason we're going to talk about this is because there are two things involved when you're generating that is the force that you apply to it to turn it so the bigger the generator you're going to have to apply more force obviously and the other thing is the speed at which it turns now we've done a little bit on gears and we know that if we gear something then we can turn it very quickly but we need to apply aggregate force so you find a lot of motors will need a gearing setup to get any usable power out of them and this tends to be true for a straightforward dc motor it's particularly true for things like adapted alternators or adapted universal motors but there is one set of motors where it's not true and these are stepper motors actually stepper motors are really quite interesting things and one of the good things about them is when you turn them quite slowly they actually give a really high voltage output so they can be very very useful for that now stepper motors and brushless motors are the ones that you're going to find in the micro generators so if you're looking at a wind micro generator on ebay and thinking about taking it backpacking to charge your phone there's a very high chance it's either running off a stepper motor or it's running off a brushless motor the commercial ones tend to be brushless motors the diy home ones tend to be stepper motors and there's a reason for that you can attach something directly to the spindle get it to turn and even if it's turned slowly it'll have a decent voltage output and so it makes the construction of the whole thing much easier when you're constructing the whole unit the only slight problem with them is working out what's inside and then how it is that you can change that so the video is going to be about how it is that we need to adapt a stepper motor into a generator anyway let's have a look at a few stepper motors close-up so here's a fine example of a stepper motor and they come in a whole range of sizes so you can get really small ones and you can get big ones and get absolutely massive ones you can either buy them i've clearly bought these or you can scavenge them for things like printers so if you have a look around in the printer you'll find some stepper motors that you can use we're going to use this one because it's a nice brand new bought in and so we won't have any surprises now we're going to need to attach to the spindle to get it to turn and the good thing about the bought-in ones are you can get all kinds of spindles and attachments these are actually from a cnc machine and so it has a little spindle that goes on that drives a tooth belt kind of awesome makes the project really really easy so there's an example of some stepper motors but they come in a whole range of types here's one it's an extremely popular stepper motor it's a 28byj it's a geared stepper motor so you've got some gears in here and that makes that quite hard to turn but if we put a crank handle on that that'll output a surprising amount of voltage so you can buy them as a package like that or you can buy them like that or you can buy them in a whole range of ways this is a stepper motor incidentally i took this from the cd-rom drive you're interested in how i got this just reviewed the video and you can see that that's a nice little stepper motor now most stepper motors you'll notice come with a range of wires and there's four on them so we have four wires coming out of that stepper motor now when we look at the wiring the stepper motor actually looks like this so those four wires in fact just go to two separate coils and we can identify those just by checking it at the resistance with a digital multimeter when you've got the right coils you'll have a fixed resistance of some value quite often it says on the stepper motor what that resistance value will be and it depends on the size of the motor but you'll get some resistance value when you get two wires that are not part of the same coil the resistance will be infinite because they're not connected so it's really easy to identify which wires they are and i've done that and i've just knotted one together to tell me that those two wires belong to one coil and those two wires belong to the other coils it's very easy to identify which two ones it is that you're looking at sometimes of course you get the motor like this which got a pin connection if you have a pin connection you'll need the connecting wire and do exactly the same thing here when we're looking at this one we can see the four dots on it with the four connections that would be where we sold it to and then we'd identify which coil it was and we could use that as a generator by spinning that this one's a bit unusual and i thought i'd actually go into it because it's got five wires on it and that can be a bit confusing this one's actually really good because you can find the pin out diagram really really easily for it just by doing a search under the name and pin out and it will tell you that the actual wiring looks like this so you can see that in fact the two end coils are two of these wires and the red one actually taps off the center of each which is quite curious so we will ignore the red and just attach to the two other two wires and it will be exactly the same as this one which is really cool now in order to get this out what we'll actually have is an ac output that's not a bad thing in itself but more often than not you want a dc output in order to get dc output we need a bridge rectifier now a bridge rectifier is a whole host of things either you can make it and it looks like this as you can see it's basically just four diodes and a little ring those diodes can be any number and there's a really popular one the one n4007 which is just going to handle it just fine you can use a 1n34 which is a very low voltage drop and you might use that for something tiny like that but the silicon diode is going to be fine like that or you can buy a rectifier as a single piece there is something called a mosfet bridge diode and i might do a separate video on that which is a little bit more complicated but worth looking at certainly and i'll probably do a video on it later what we're going to do is we're going to build two diodes and attach them to each of the coil then we need to connect the coil together now when we generate from this what we're actually going to do is store that energy in a capacitor so we're going to charge a capacitor up and use the capacitor to deliver the power and the circuit that we're going to use looks like this now we obviously have a choice we can connect that up in parallel or we can connect that up in series if we connect it in parallel we'll have the same voltage but we'll have more amps if we connect in series will have the same amps but more voltage it just depends what you want so the first thing to do is to build those bridge rectifiers okay so this is what a diode looks like and its circuit diagram so here's some 1n407s in real life and as you can see they've got that silvery bit there and that's the cathode it's the same bit as the flat bit on the diagram now to make a bridge rectifier really is a piece of cake just take two with the silvery bits pointing towards each other and twist them around and then take two with the black bits pointing towards each other so the silvery bits are there and this time twist the black bits around now what we have to do is take the two that we made connect them up like that and twist them around and that's it when we soldered them together we've made our bridge rectifier it really is that simple so i've opened it up into the little diamond shape so it looks just like the circuit diagram you can have them in any orientation as it happens but that one really works nicely and you can see what it actually is now the connection to the motor goes here and here where we've got silver black silver black that's where the ac input goes in so your motor coil connects there the output is from these two when we've got silver and silver together that's the positive where we've got black and black together that's the negative which is kind of really easy a black black negative now we could use it just like this but actually as a rectifier it doesn't give a particularly smooth output so we can put a capacitor on it to smooth that output the capacitor not only smooths the output if it's of high enough value it will store energy and so you get a much more even output now i've got a 50 volt 1000 farad capacitor here it's just a normal electrolytic capacitor you can put quite high farads on there 5000 would be just fine drop it down to 25 volts just fine i happen to have quite a bag full of these ones so that's the one i'm going to use and it anything around there will work just great now when we connect it you'll notice the electrolytic has a negative sign on it telling you which side is negative so the negative connects to the negative and the positive connects to the positive on the output so it's going to connect just like that and it'll do that on the other one as well when we've done that these will be the outputs where we connect them together in series or parallel one coil will go here and then on the other one that we've made that's where the other coil will go so i'm just going to twist those around solder them together and you should put some heat shrink on there as well just to make it all nice and neat and tidy okay you can see what i've done i've identified the two coils and then i've taken one coil and soldered it onto here remember they're the ac inputs of our bridge rectifier leaving the dc outputs alone and across those dc outputs have basically put a capacitor and that's what it looks like and here it is where i finished it off so i'll finish that one off and then the two finished off now to connect these in series you would take the negative and attach it to the positive so that we have negative to positive like that then that obviously would be a negative out and that's your positive out so that's in series to connect them in parallel we connect both the negatives together and burst the positives together and that's in parallel now remember in series the voltage adds and the current remains the same in parallel the amps of current add and the voltage remains the same so i've gone for a series connection so i've connected negative and positive to each other of these ones taking the negative out there and the positive out there and i've chosen a black and red for obvious reasons and here it is going to the nema stepper motor so here it is connected up to the multimeter it's reading a vault reading and i've connected a spindle on it just to make it easier to turn and if i just get my hand out of the way so you can read the voltage reading with no problem getting that up to 14 15 volts just turning it by hand now i've put a spindle on because you can buy this stuff this is toothed belt you can buy it in yards actually that tooth belt fits on there so we could drive this from absolutely anything using a toothed belt on that spindle okay so i've got five leds in a row attached to it let's give that a spin [Laughter] so there you go how to convert a stepper motor into a generator now when i was turning that you might have noticed that the leds didn't light initially and then when i stopped turning it they stayed on for a long amount of time that's the effect of the capacitors the bigger those capacitors then the longer that effect will be so it'll take longer to charge but it will last longer when you're not actually turning it so if you stuck a couple of super capacitors on there at 500 farads it'll take you a while to charge those up but certainly would last an awful long time when it was discharging which i think is pretty cool and well worth experimenting with to really create something that meets your needs these are awesome things to turn into generators and this is about nema and it's quite a large nema motor it's not brilliantly large but it's quite large but it's a bought motor and i did it deliberately because we can fit things to it but if you want to scavenge stepper motors they're all over the place like i said they're in cd rom drives dvd dvd-rom drives printers cnc machines there's just a whole plus of places where you can get a decent stepper motor and then of course this this is the kind of motor that's very often used in macro generators particularly the diy macro generators anyway i thought i'd go through that because i think it's quite interesting it should be useful i hope and i hope it sparked some ideas and thank you very much for watching

Channel: Robert Murray-Smith

Views: 41,988

Rating: 4.9311137 out of 5

Keywords: stepper, motors, generator, conversion, fwg, robert, motor, energy, generation, power, electronics, science, fair, project, stem, steam, murray-smith, design, technology, engine, build, home, built, made, adapted, converted, recycle, recycling, diy, d-i-y, how to

Id: -zCTggoh994

Length: 14min 40sec (880 seconds)

Published: Fri Jul 24 2020