Inside a Washing Machine Motor: Explanation, Pinout, Teardown AND Experiments

hello friends in my last episode I've shown you a teardown of a Zeman's washing machine and I did that in order to show you how you can salvage an electric motor and a fitting belt transmission in this video I'm now going to go a step further and take a look inside one of these motors in order to show you how to find out their pin out and how to in principle power them with both AC and or a DC and after that we're going to explore some of the things happening inside the motor and talk about the differences between this type of motor and an ordinary DC motor so here is the Zeman's washing machine motor that i salvaged in my last episode but it is kind of precious to me because it came with its own transmission and that is why I don't want to take it apart instead we will take a look inside one of these Milliband washing machine motors here that I happen to have a couple of and that I also want to use for future projects it's a little bulkier a little more rugged but very similar in build and works on the same principles so let's take a closer look at this motor and then take it apart we have again a pretty small pulley for a ribbed belt sitting on the pretty massive motor shaft and then we have this bulky rectangular stator pack or package made from transform illumination that was also welded together on the backside of the motor we have a plastic cover and we find a tenpin connector and one of the main reasons for this video is to show you how to take a look inside of one of your motors and find out the pin out of the connector on your motor because without that a motor like this is pretty much useless to you but let's take a brief look at the nameplate first and this motor by the way is salvaged from a 25 to 30 year old miele washing machine and those are just as easily available now as the Siemens washing machines in the last video it also says moto fu jager but weep on here and that means that this motor must be regulated and that is between 300 and 11,500 revolutions per minute which it states down here and we're going to talk a little bit more about that later in this video so I begin to tear down by removing this plastic shield here and it seems to serve a double purpose for one maybe it protects the inside of the washing machine a little bit from the dust coming from the brushes inside the motor but it also makes the motor a little quieter I think and that is why we have some insulation material in here and in the next step I remove this metal arm here and I do that by unscrewing a bunch of rather thick Torx screws and that is something that you didn't see too often in Germany thirty years ago but in these older Miele washing machines you can already find torques all over the place and on the backside of the motor we can now see a plastic shield connected to the motor by four screws and we remove those as well but we can see that it's actually not one piece but two pieces of plastic that are connected together and by unhooking the top cover here I can take it off and we can take a closer look inside and we see traces leading to our ten pin connector and we can see that two of the connectors are pretty charred we'll take a closer look at that in just a second and then we can try to wiggle off this entire plastic shield but you have to be very careful because you don't want to damage the motor brushes that are connected to this plastic part and here on the backside of the motor shaft we can also find a small permanent magnet and that is used in conjunction with a coil sitting in an plastic shield in order to read out the motor speed and control that but we're going to talk about that in another video but we can now start to determine and write down the pin out of that ten pin connector and for that I have taken this picture here of another well optically is slightly different but electrically identical shield I took this from another motor of the same type now we have seen that these two traces here just lead to this tacho coil and we can write that down so let's take a look at those two pins that are a little burned or charred and we can see that this is actually a component that we can pull out here and what this is is a temperature or a thermal switch and let me demonstrate how that works so as you can hear the continuity tester of the DMM shows us that this temperature switch is conductive now I'm heating it up and as you can see now it has switched off and we wait for a while until it has cooled down again and now it's conductive again so this is just a safety measure used to protect the motor from overheating and let's write that down our little pin out diagram here as well the outermost pin on the left side simply connects to a resistor at 10 mega ohm resistor that just ends in the air right now normally this would be connected via one of the screws that I removed to the housing or enclosure of the motor and this is where PE the protective earth connector would be connected with that you can also see on this connector cable for the washing machine motor but well when you operate this motor on your desk for example it might be smarter to connect the protective earth directly to the housing and remove that 10 mega ohm resistor but I don't want to give any conclusive advice about this yet we'll have to talk about these safety issues once we are really running it via the line voltage in this video I'm kind of doing that but I'm using an isolation transformer and when you have an isolation transformer a connection to protective earth wouldn't make any sense if you don't know what I'm talking about watch my video about the power grid which I linked in the video description so the 5 pins that we have determined so far are important for safety and control aspects of the motor but they are not crucial if you just want to power up the motor so let's get to the really crucial parts and among those are these two brushes here which connect to the commutator and power the armature of the motor and the brushes are connected to these 2 pins here and let's write that down in our little diagram here as well and the symbol that I use here for the commutator for the armature is the same one that you use for ordinary DC motors with permanent magnets the little black things touching the circle in the middle reading em are supposed to be the brushes but this motor is not a DC motor at least not a DC motor with permanent magnets it's a universal motor and what that actually means well we'll have to talk more about that but one thing that it means is that this motor has field coils or field windings and they are connected to the remaining pins so let's explore that a little further so if we take a closer look at the Stata pack and the field coils themselves we can see for actual connectors leading to the coils and the plastic shield has four blade connectors but only two of those connectors actually connect to the field coils while two of them just go into these plastic indentations here connecting to nothing and that is because two of the connectors on the field coils are just two ends of the coils being connected together by this little piece of metal here and that simply means that a few coils are soldered together in series and that only it's two ends are effectively used and let out of the motor so we have two Center tabs or taps of the field coils if you want that were never used with this motor though so now we have the complete pin out and well one of the ten pins is actually not connected that's why it says NC you know that pin just leads to those two blade connectors that just go into the plastic indentations and lead nowhere but with a pin out we're now able for the first time to power up the motor and I'm now going to do that in the most simple way possible and that is by simply connecting the two field coils and the armature in series and that is the standard configuration for the universal motor and well typically Universal motors are powered by AC and that is what I'm going to try now and I'm using my adjustable isolation transformer here and I will step up the supply voltage to around half what it's rated for that is 115 volts out of 230 [Music] [Music] so here again we encounter a problem that I have tried to describe and solve before in my earlier videos about washing machine motors and that is if you have a series wound DC motor or a universal motor and you power that up without actively controlling the motor speed then it will just go through the roof and the motor will turn faster and faster and faster and even with only half the supply voltage and no mechanical load on the motor shaft 11,500 rpms is left behind very quickly and this can be harmful for the motor and is also not very useful for most applications now I have used a motor like this successfully before without speed control and that is when I build my ducted fan in the ducted fan project the thing is that you have a constant or at least a constantly present load and represented by the air and the air resistance so that the motor will settle down at some kind of maximum speed but well I still operated it at only I think 80 volts or something if you want to have something like a robot or a vehicle or anything where you need more precision control and more torque and less motor speed then you will have to control the motor more sufficiently and it is not enough to just connect it to the line voltage but I have presented one solution for that in my video about how to reuse washing machine motors and that was in the form of a very simple thyristors circuit that kept the motor at constant speeds but it had its limitations maybe I can still improve it but right now I'm working on a completely different approach to solving this problem so let me show you what I'm talking about so you can already see me connecting the motor to my self-made lab power supply here and I'm doing that because I want to use two independently regulated DC voltages to control the motor let's take a look at the simple circuit diagram again and let me explain to you the different options that we have we had connect the field coils and the armature in series and used AC to power the motor I would call this the universal motor mode of operation now if we were to use DC instead of AC then we could call and see this motor as a series wound self excited DC motor series wound because field coils and armature are connected in series and self excited because the external field in this data is not generated by permanent magnets but by field coils but also self excited because the current flowing through the armature is the same current flowing also through the field coils meaning that the current through the field coils or the voltage across the few coils is not independent of that across or through the armature and that's why that's called self excited now if we were to connect the field coils in parallel or in shunt with the armature we'd call that a shunt wound DC motor and it's again self excited because the voltage across the two things here the armature in the field coils are not independent from each other but if you separate both and then have two independent voltage or current sources powering the armature on the one and the field call on the other side we're talking about a separately excited DC motor it's neither series nor shunt wound because the two elements are not connected together and using this motor as a series wound DC motor is basically what I did back with the thyristors circuit because that actually used DC as well but well the field coil and the armature were still connected in series connecting the two in parallel doesn't really make any sense because the field coil has a very low resistance and it is just not built to handle the large voltages that we can put across the armature the few coil were just overheat and well the insulation would melt at some point doesn't really make much sense so the other option here really is to control the two separately and let's just try this in a little experiment the analog voltmeter shows the voltage across the armature and the analog ammeter shows the current flowing through the armature the reading on this read seven segment display here is the voltage across the field coils and the DMM displays the current flowing through the field coils we are now applying a voltage across the commutator and the motor starts spinning yet other than in the example before it now will not run away but stay at a constant speed or at a maximum speed we're stepping up the voltage across the commutator and of course the motor speeds up but again it keeps its speed and let's go through 30 volts and we can see the same result now we can adjust the motor speed and torque by adjusting the voltage across or the current through the field winding let's step up that current and as you can hear the motor speed goes down and when we decrease the voltage across the field winding or into the current through it the motor speed goes up thirds of course best if you control both the voltage across the commutator and the current flowing through the field winding but in theory you can have a fixed supply voltage for the motor and then a variable voltage or current for the field winding in order to control the motor let's make an additional observation here I now shut down the current through the field coils completely zero and pair and I keep a voltage across the armature and as you can see the motor is still spinning and even speeds up but I can now very easily just grab the shaft and stop the rotation because there's almost no torque here so why does that happen well we'll hopefully understand it later in this video but in order to make that happen it's maybe time to learn a little more about the field coils themselves why are they even there here we have a windshield wiper motor just an ordinary DC motor like it would be used in automotive applications we open it up and inside we find an armature that looks not exactly like the one from the washing machine motor but it has a lot of similarities there is a commutator here for example and commutator brushes but when we take a look inside the housing of this DC motor we find permanent magnets it's what in German is called a permanent a zig-zag leash to a motor a permanently excited DC motor may be not a very usual English word so most people just call it a permanent magnet DC motor or something like that but here for example we have a Brett cutting machine that I found on the trash the other day and let's take that apart and inside we find a universal motor and this universal motor again has an armature a commutator brushes but then this weird state a pack and a coil sitting on it and the difference here really is that this motor is not powered by DC but by AC by the line voltage and for some reason it is necessary to have a field coil rather than permanent magnets if you want such a motor to be powered by AC well why is that well let's take a look at another little experiment so here we have our state a pack with the two field coils in series and that are now going to be hooked up to our lab power supply right in the middle I have now placed in ordinary compass and that is sitting on just a piece of rubber that puts some distance between the surface and the compass itself I will now apply a voltage to of the field coil and you can see a rearrangement of the needle and the rough direction or orientation of the flux lines inside the stator pack is like this but when I now reverse the polarity of the voltage across the field coils you also see a 180-degree rearrangement of the magnetic needle so by reversing the voltage across the field coils the direction of the current flowing through these coils is also reversed resulting in a reversal a 180-degree reversal of the flux lines inside the stator and this can also be used for example to reverse the rotational direction of the armature in such a motor it is also the reason why it is possible to use such a motor rather than an ordinary DC motor with permanent magnets with AC because when you connect an alternating voltage an alternating current with periodically changing direction will flow through the field coils also creating a magnetic field inside that will likewise change its direction periodically and the same thing happens at the same time in the armature so these two 180 degree reversals are synchronous and they can't should cancel each other out while when you apply an alternating current to a DC motor with permanent magnets only the field in the armature reverses while this field here stays stationary and therefore no rotation comes to be so when repurposing a universal motor as a DC motor like what I'm doing here it would actually not be necessary to have field coils you could just have permanent magnets but one thing that is good about field coils as well is that you can strengthen or weaken the field in the stator which then results for example in more speed or otherwise more torque in the rotation of the shaft as we have seen in the experiment before so since the washing machine motors come with field coils we might as well use them to our benefit but I wanted to explore the magnetic field inside a little more so I took now this very small compass here to see how the field lines within the stator are arranged and it seems that they are pretty much parallel and in order to get a better picture I also got myself some iron filings and let's see what that will look like well of course it's a little more complex than just straight lines that are in parallel to each other but I think it's pretty close but when we shut off the current of course the iron filings collapse but still if you now insert a compass into the stator pack there is still a rearrangement of the needle well and why is that I mean if I try to stick the iron filings to this data they just fall through it well the answer is that there is still a weak magnetic field here a remnant magnetic field because some of the magnetic domains are still pointing in the direction that was once forced by one of the few coils when a current was flowing through them and that is also the reason why the motor still rotates and even speeds up when I shut down the current through the field coils entirely the remanent magnetism of the state effect and here I have now completely removed the field coils themselves so that you can see what the pack or package actually looks like and here again you can witness the reaction of the needle to the remnant field but there is one more little thing that I wanted to do because I said that you could use a motor like this also with permanent magnets and I just wanted to prove that to you so I have now put the motor back together missing only one very crucial piece and that is the stator itself or the stator pack with the field coils and when I now step up the supply voltage across the commutator or armature the current goes up but the motor doesn't rotate now let's try something a little different here the demonstration here we have an ordinary iron file and on that is sitting a strong neodymium magnet and I'm just placing this you're roughly on top of the motor now let's step up the voltage again and it's give up you see that let's give them what a little momentum with my hand it's struggling but you can't see that there is a rotation and that should suffice to show you that you really only need a stationary magnetic field when powering such a motor with DC and you could add permanent magnets this type of motor if you wanted to and use it with DC and not use the field calls at all so that was today's episode and I hope it helped you a little bit in maybe figuring out the pin out of a washing machine motor that you have lying around somewhere and that it gives you an idea what kinds of modes of operation there are for these types of motors and maybe also you learn something about the differences between Universal motors and permanent magnet DC motors now I'm using my experimental setup here with the lab power supply to determine just the right values to build a much simpler circuit that I then hopefully will present to you guys as a simpler solution to this problem on the other hand I have also started to work with the Arduino and build something like a motor shield for the Arduino so that we can for example control the speed of these motors by having sensor readouts for example of the tacho coil or other sensors like magnetic sensors that I have used before and then I'm also working on a mechanical drivetrain so that I can use maybe two of these motors as a drive for a robot or some kind of small electric vehicle so those are at least three extremely interesting projects in my opinion and the next couple of videos will revolve around this topic again so if you like these ideas if you like the little experiments that I've shown you or other things please let me know in the comment section and if you can spare a buck or two well then maybe think about supporting my channel on patreon.com /tpa I sure could use it and it was helped out a lot so I hope you like this and to see you soon

Channel: The Post Apocalyptic Inventor

Views: 1,118,975

Rating: 4.8776975 out of 5

Keywords: Miele, Miele Washing Machine, Miele Washing Machine Motor, Miele Motor, Washing Machine Motor, Electric Motor, Universal Motor, DC Motor, DIY Motor, AC Motor, Induction Motor, Miele Germany, Made in Germany, Siemens, Siemens Motor, Siemens Washing Machine, Siemens Washing Machine Motor, Bauknecht, DC Motor Control, Speed Control, VFD, Variable Frequency Drive, Shunt Wound Motor, Series Wound Motor, Electric Motors

Id: CtulRqznbzI

Length: 25min 22sec (1522 seconds)

Published: Sun Aug 27 2017