26-04-2013, 11:02 AM
Regarding magnetised screw drivers If you one of those instant heat soldering guns, simply pass the screw driver through one of the elements/tips or make another from a longish piece of large diameter copper wire.As some says all you need is low voltage AC magnetic field. I notice milling cutter also get magnetised which can be a bit of a nuisance. I made a growler several years ago, and use it for de-magnetising larger things. For those not in the know, a growler was a common device often found in larger garages years ago and today in motor rewind shops for locating armature and stator faults. Basically it is half of a transformer. Mine was a large low voltage transformer,I removed the low voltage winding and carefully milled away the core to form a VEE so that I could lay an armature in the VEE. When the primary is connect to the electric supply and with an armature in place it becomes the secondary, and with a 6" steel rule or a piece of broken hacksaw blade placed just above the armature it will vibrate in simpathy with the 50Hz mains.I used my growler to locate faults on car and motor bike dynamos, its a quick,cheap and simple test.There is another type or shape for fitting inside motor stators, the principle is the same. I'm sure there are other more modern tester on the market, but mine works.Ted
