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Forum Index : Other Stuff : Tool Improvisation
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MacGyver Guru  Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Crew I was cruising down the road last week and spied a dishwasher in someone's trash. Excited to recover the copper coils from the motor, I asked the homeowner if I could snag the motor and he gave permission. When I took a closer look, the motor was nothing like I expected, rather this is what I found: 
It's about the size of three packs of cigarettes stacked together. On closer examination, I found out it was a PM (permanent magnet) motor, so I was less disappointed, cause this is a ready-made generator, if you don't mind the fact that it "cogs". Cogging is the term used to describe the beat or vibration the magnets make working against the iron core on each revolution. This puppy beats twice per revolution, but it was free, so who's complaining? I yanked off the pump cover and found this: 
It turned ever-so-freely, I didn't want to tear it apart, so I decided to "improvise" and make a coupling that would fit over the pump impeller and merely attach it to an arbor to which I will eventually attach blades. The problem is, this requires a mill with enough travel to make a decent slot. I have an end-mill milling attachment for my lathe, but it's nearly useless. By the time I get it set up, there's nearly no working room left. That's one disadvantage to using tiny machinery, but I still like small stuff, so I had to find another way around this. 
Here's what I came up with. It's a "Dremel" router table. I picked it up from Amazon.com for $30 including shipping. It's all plastic (except for screws) and it holds my 110 vac electric Dremel high-speed drill thingy. 
Here's a shot of the Dremel tool mounted to the router table. It just clamps in with a couple special clamps that you hand-tighten in place and it's made to fit the Dremel tool EXACTLY. There's a depth-of-feed adjustment and a lock-down thing so you can choose the depth of the cut you want and lock that dimension into place whilst you whittle away topside. 
Here's the "quill" sticking through the top side at the business end of things. That side guard is a moveable "fence" which allows you to slide your work against to maintain the proper distance from the cutting quill. I said all that to show you this: 
This is the slotted coupler I manufactured out of Acetate rod. It will fit onto an arbor (the windmill's main shaft) and couple to the little pump impeller and everyone will be happy as a clam without my having to tear things all apart and probably botch everything up doing so. Here's the finished product sitting atop the little PM motor that used to be a dishwasher water pump: 
I tapped in a 1/4-20 set screw into the side to hold it to the windmill shaft. The blue lines are layout lines I used to cut things the proper length and to measure hole depths with accurately. And the point of all this? Well, it was just to say that in the face of either no tools or at least not the right tool, there's always a way. Sometimes we have to "Improvise" in order to get the results we want. Not counting the wood I used to fabricate a little working platform for the tool, for around $30 I made an end-milling, slot-cutting device that will serve me well for years. I'm told 'necessity is the mother of invention'. I'd go it one step further and say "Improvisation is the mother of innovation". Sometimes you're pressed to build a spaceship with just the junk in your pockets. I wouldn't be able to call myself MacGyver if I couldn't at least approach that a little bit, eh? 
Edit: Bigger pictures Here! . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mack Some people can make something from nearly nothing and other people can make nothing from a lot. Good innovation mate a very handy little tool but keep your fingers clear as it will find the tomato sauce {ketchup USA translation} really quickly. All the best Bob Foolin Around |
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| grub Senior Member  Joined: 27/11/2007 Location: AustraliaPosts: 169 |
That looks like the pump motor to me. Just about all washing machines use this type of pump now. |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
grub Yup, it is! Good to know this: "Just about all washing machines use this type of pump now." for two reasons. First off, I'll stop looking to get copper motor windings out of junked dishwashers. Secondly, if this little thing makes anywhere near a 'good' alternator, I'll build more. The coupler I made yesterday works like a champ. . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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| MacGyver Guru Joined: 12/05/2009 Location: United StatesPosts: 1329 |
Follow-up Report 
Took that pump apart today and here are the major players. 
Here's a closer look at the PM (left) iron laminates (center) coil (right). 
The plastic thing the coils are would around folds, so to rewind this would be fairly easy, if one were of that intention. 
Not too sure what this little magic part is. It looks like tiny coils inside a plastic housing; maybe a sensor of some sort? 
Anyhoo . . . here's that finished coupler I made with my new Dremel table toy. I have it chucked up in my 18-volt high-speed drill motor. 
Here's what I used to spin the pump motor. I ran it as fast as it goes and I'm thinking that's around 2,000 rpm or so. At that speed, the little "generator" was able to make a 12-volt (d.c.) automobile running light bulb just barely glow. I hooked it to my volt meter and I think it said 22 vac, but my meter has only two a.c. settings; 200v & 750v. I don't own an ammeter (don't need one for plumbing) so that's why I did the bulb test. My opinion of this pump being converted to a windmill electric generator is: Don't bother! The results I got were dismal at best! . . . . . Mac Nothing difficult is ever easy! Perhaps better stated in the words of Morgan Freeman, "Where there is no struggle, there is no progress!" Copeville, Texas |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Hi Mac, I expected those results, but you were having fun and thought you would work it out sooner or later. As for the little magic thing, i am guessing its a thermal fuse so if there is a fault the coil wont go into meltdown and the fuse will go open circuit. I dont think it would be worth a rewind and would keep the coils for the copper wire on another project. Pete. Sometimes it just works |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
Hi Mac Ah its a learning curve, but like Pete said your having fun. I have a couple of those little motors. Its a clever idea, the permanent magnet armature is inside the plastic case, where the water is, behind the impeller. The coils and laminations are on the outside, where the water isn't. The design means there are no drive shafts through water tight seals to worry about, it cant leak. The down side it the armature rides in plastic bearings that use water to keep them cool and lubricated. Take away the water and it wont last very long. The little magic part is a thermal overload circuit breaker. If the pump runs dry or is jammed ( usually with dead frogs ),it starts to overheat and the breaker will cut in and out to stop it having a melt down. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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| grub Senior Member Joined: 27/11/2007 Location: AustraliaPosts: 169 |
Even if full of water all the time, the dirt and grit in the wash water eventually wears out the "bearings". This fault manifests itself by intermittantly not running, then running, until it doesn't run at all. Something to keep in mind if your washing machine starts to play up. |
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