MJLorton Solar Power and Electronic Measurement Equipment Forum
General Category => General Discussion => Topic started by: SeanB on January 13, 2016, 01:09:31 PM
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Thought I might start a general thread, what you dod today that you thought might be interesting to all.
To start it, today I was rewinding some relay coils, to change them from a standard 24VAC coil to a slightly non standard 36VAC coil, as the original coils and contactors are a 3 month delay on the slow boat from China, and are the same poor quality. Steel contacts and steel terminals, not exactly the beast.
So, bought some GE contactors, made in Poland, and unwound the one to get the turns count ( 522) and rewound it with 850 turns of a slightly thinner wire ( so as to still fit the former) that I ordered from RS Components as part of a larger order. Naturally, being RS, 3 out of the 4 are ex UK stock, and will be here next week. The wire was the only item in stock locally, so was next day, even before the payment cleared. So, spent a pleasant 2 hours unwinding and rewinding 2 coils, multitasking doing so as receptionist. 5 calls in that time, lucky I had a pen and paper to use as a counter. Cleaned the wire ends with some sandpaper and soldered them to the terminals, and put them in and they work, 7VA power consumption.
Now, what to do with 1km of 0.224mm wire, still have 30km of 0.5mm wire that has been around a long time, but too big to use here.
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Oldie and newie ;D thanks man!!!
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Bought a sale LED backlit monitor for $15 at the local China mall, on sale because it is missing the power supply and remote. 1366 by 768 40cm panel, and it works. Sold as a TV set, but I plan to use it as a monitor, as it has HDMI, VGA and RCA inputs as well. Branded TEAC, but could be anything under the case. Just tried it with a generic 12V 2A wall wart, and it seems to function, though I did not apply any signals to it yet.
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I'm going to give my new PICKIT3 a try tonight; I never use MPLAB IDE as I think it's a very poor and confusing IDE, so I just throw my source code files at the compiler and out comes a hex file to flash onto my chips; the good thing about that is you learn more about the compiler and chips than you would if you let your IDE do it all for you.
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I returned back to a project I'd started a while ago on one of my breadboards as I want to get it finished up and out the way; it's a circuit that reads some car sensor signals and displays them on a lcd and you can use a rotary switch to "page" through the various sensors readings etc. I hit a brick wall a while back because I rather stupidly choose to mux all my adc signals as I needed more inputs than I had adc lines on my PIC; so with fresh eyes last night I took a look and it turned out to be simple! all i needed was stronger pulldown on my 2 buttons which were being mux'd through a CD4053; hobby electronics can be cruel sometimes! lol
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Well, making some scrap metal, and doing data erasure on old hard drives. Started with a big box of assorted drives, and now have a pile of mostly aluminium parts and another box of stainless steel covers and screws.
Now have a big pile of crescent shaped neodymium magnets on pole pieces to play with, along with a number of aluminium platters to bend. Some have had the data literally scrubbed off by the damaged heads, which makes a lovely grinding paste inside the drive.
Sizes ranged from 40G to 3T on them, majority 80G and 500G.
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Precision standards are not something I use everyday. For most things close is good enough. I wanted to experiment with building a low noise voltage reference. So I have fired up some things that don't get powered often. Trying to figure out what is stable and what can be believed. Been comparing readings and what seems to track together. Like the old saying......One clock in town, everyone knows what time it is.
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Today I dug out another Dial A Source DAS-56A and now I have at least two things that somewhat agree. Found a Fluke 8520A I didn't know I even had. Powered it up and a 15 ohm resistor flamed out, shorted tantalum on a 27V buss. It still had the mark of the devil on the display, 66666. Still looking for
the differential voltmeter.
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lol sorry, I had to delete my previous post as I was going to add some text waffle about what I had been doing, but then had to do something else, and when I came back, I forgot I had attached a picture.
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It still had the mark of the devil on the display, 66666.
lol
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Now have a big pile of crescent shaped neodymium magnets on pole pieces to play with, along with a number of aluminium platters to bend. Some have had the data literally scrubbed off by the damaged heads, which makes a lovely grinding paste inside the drive.
I quit scrapping hd's, the return on the aluminium was not worth the time. However, I still salvage the neo's although they are not nearly as good as the neo's in the late 80's early 90's drives! I think those neo's are worth more than the scrap! :)
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Got the magnets off the pole pieces eventually, by soaking for the last 2 weeks in a jar filled with methyl ethyl ketone solvent, to dissolve the adhesive sticking them on to the pole plates. now have a tower on the fridge door, amd the last few holdouts soaking in the bath of solvent. Some came off easy, but the stubborn ones took a while, as i did not want to break any, and only broke a single thin one.
Magnetic indicator film comes in handy though to show you how the field inside is arranged, some are not just a single pole on each side, but a pair of poles with a common centre.
Yes, the amount of money for the scrap is not much, but I had a lot of extra scrap to go with it. There was only 6kg of aluminium and steel in the 20 odd drives.
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So, bought some GE contactors, made in Poland, and unwound the one to get the turns count ( 522) and rewound it with 850 turns of a slightly thinner wire ( so as to still fit the former) that I ordered from RS Components as part of a larger order.
How do you calculate the turns?
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Wound till the former was full, like the rest of the coils.
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I have to leave town next week. Have a friend that is going to feed the dog. I decided build an automatic water bowl.The white tube on the bowl is the overflow which goes to a floor drain in the basement where the dog door is. The black tube is the fill line going to an old washer solenoid valve. I knew if I waited long enough I would find a use for this. The other valve has to be capped or else it would leak. These valves have to have positive pressure on the inlet to seal. When filling, this valve jolts like a rocket. I had to put
a small sponge inside the inlet port to slow down the flow.
I was visiting a friends shop two weeks ago when I saw some capitol equipment waiting to go to scrap and grabbed two of these plug in dual event timers. It just so happens that I used to work for the company that made these timers and they are micro processor based, set up from 1 second to 100 hours. So it is like I built this. I operate the valve for five seconds every hour. Any overflow goes out the white tube down the drain keeping the water fresh. A spare set of relay contacts resets the timer and the process starts over.
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Nice use for the asymmetric recycler, and good for keeping it from the scrap pile and giving it a new use.
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Things going to scrap.........
A week later I was back for a repair and decided to get the rest of the sockets. Good plug in sockets are more expensive than the plug in modules. Figured I might as well take the other four timers made by another company which were older. Only one of them worked and that was intermittent. Opened one up and the zener/line capacitor power supply was toast with burnt circuit board and poisoned solder joints. The other three had exactly the same problem.
So, a serviceable $10,000 piece of equipment went to scrap because a service tech stopped after putting in just two new timers.
I'm sure the engineer who designed the timer did all the thermal calculations and came to the decision that the timer would survive the printed specifications. Except, these often get placed in a hot environment with no air circulation, operate at slightly higher voltage and get coated with dust. I see so many of these minimal designs that only manage to work for 5 years contributing to the worlds scrap.
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I did the same, replacing some timers. Sure the original designer of them at Siemens in the 1960's did not think they would still be running nearly a half century later. The only reason I replaced them was the contacts on the relays finally were worn out, and had gone intermittent. The power supply of the timers was fine, even if the capacitors are tired, the resistors are weeping wax and you no longer can get unijunction transistors easily. The actual Siemens relay used inside is still made, but to get them was more expensive than the replacement Omron timers and the sockets, plus the original timers use a not very common socket, which has soldered contacts and is not DIN compatible.
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nothing i'm finding new ideas