This is a bit of a tangent, biy I had a vaguely similar problem.
The problem was described as the slab break detection sensor causing an emergency stop on a gang saw - sort of like an oversize bread slicer for granite blocks - the 'slices' come out 2 inches thick by about 6 feet x 8 feet. I had never seen a gang saw before, let alone fixed one. After the operator showed me the problem, I reviewed the schematic, and the slab break sensor was not tied into the emergency stop circuit. The error code traced back to an inverter alarm - over-voltage. By roundabout descriptions, when the slab break is detected, the drive motor (and 8 foot diameter flywheel) is braked to a stop. That was when the symptoms finally pointed to the braking resistors for the inverter. There were 3 braking resistors, and one had a burnt-out section. I spliced the resistor back together - less one turn to remove the burnt section. And then the slab break sensor problem was fixed.
Good suggestions, Jon. It was a tad easier when I was a kid and there were tons of science-based toys. There were also tons of build-it-yourself kits such as Heathkit. Heathkit is still around, but it's not as easily available as before.
Hi, Rob. Although toy stores don't sell chemistry sets today, parents can buy many fun kits and activity "packages" for kids interested in science and technology. Science Kit lists many, as does Ramsey Electronics and Jameco Electronics. Perhaps some CAD-and-animation experts can create graphic "construction" projects that let kids assemble a small motor in virtual space. The software would include the pieces and have the kids assemble them in the right order to create something that works. Simple projects such as a wind-powered generator, weed-wacker 2-cycle engine, small generator, and so on would get kits interested enough they could start to do things with real tools. Lightwave 3D, for example, can create and animate solid objects nicely.
Like others, I too, have had similar experiences fixing "stuff." I hope all our experiences are symptomatic of a spirit of willingness to try to fix things instead of running out to buy a new model which many times is no better or even worse than what we are trying to fix. In that spirit, opportunities abound, and here in the Chicago area, an entrepreneur has expanded his 16 year old company (corecentricsolutions.com, Think Green division) to include the remanufacture of "no longer serviced" parts for appliances such as stoves, refrigerators, etc. This gives the DIYer a chance to keep equipment running. As the Brits would say, "Full marks" to all of those willing to try to fix a broken, but otherwise good piece of gear.
I am impressed that the repair was that simple. What I have been finding for a few years now is that the design skimps on copper and skimps on iron, and so when the line voltage rises a bit the iron saturates and the current rises and there is a failure exactly as described. Of course, sometimes poor insulation makes things fail even faster. But the most common response of the manufacturer has been to put in a nonresettable thermal fuse, usually implanted in the winding where it is hard to find. REmoving the failed thermal fuse and adding a regular fuse will often repair the system, and assure that it is still safe and won't start a fire if it fails. Of course on many occasions the thermal fuse just gets bypassed. Yes, the product may fail again some time, but I have not had it happen yet.
I am wondering where these thermal fuses come from, they usually have no markings, and I really wonder where I can buy some of them. My guess is that they are poorly calibrated and that is what causes the failures.
By the way, gift subscriptions to Popular Science or Popular Mechanics (perhaps both!) might spark a kid's interest in DYI projects and learning how to use tools. I just learned an interesting trick to silence noisy chains in the March issue of PM.
I'm with you on this one, Jon. If I didn't have the willingness to fix things, my first car -- a Corvair -- would not have lasted two weeks. I literally had a rubber band holding the choke in place. I grew up believing that you first try it fix it yourself before taking it in for repair. It was pretty much culture-wide when I was a kid.
We seemed to slide into the no-fix-it mentality when kids stopped taking home-ec and shop in school and when parents became so protective they wouldn't let their kids "do stuff" that involved tools, chemicals, or electricity. I grew up in the Sputkin era when kids tinkered with cars, built electrical and electronic "stuff," and experimented with chemistry sets in basement labs. Thomas Edison was my hero.
My brothers and I used hand tools and watched our dad, uncle, and grandfather make and fix things. A friend's dad had a small metal lathe, drill press, and other tools that we felt comfortable around and learned to use. Mom used to complain that my brother Chris and I brought home more junk from the local dump than we took. We disassembled washing machines and lawnmowers for motors and stripped TVs and radios for parts--that is, if we couldn't repair them.
Unless we instill a hands-on do-it-yourself attitude in young people fewer and fewer adults will have the interest or aptitude to fix things, let alone design them.
Festo's BionicKangaroo combines pneumatic and electrical drive technology, plus very precise controls and condition monitoring. Like a real kangaroo, the BionicKangaroo robot harvests the kinetic energy of each takeoff and immediately uses it to power the next jump.
Design News and Digi-Key presents: Creating & Testing Your First RTOS Application Using MQX, a crash course that will look at defining a project, selecting a target processor, blocking code, defining tasks, completing code, and debugging.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.