- Greeting`S' - Steve asked a good question about rewinding coils. Can the wire size be increased? Let's look at what happens. Suppose there is a coil wound with #28 magnet wire which fills the available space. Further, it draws .5 A when connected to 15 V which means it has 30 ohms resis- tance and dissipates 7.5 W.
Next, the winding is removed and replaced with one of #25 magnet wire which has twice the cross sectional area which means half as much resistance per foot. Because each turn now takes twice the area on the coil form, only half as many turns can be wound before the coil fills the available space. The length of wire used in this new coil is right at one/half that used in the original. Okay, half the resistance per foot and half the footage means that the new coil will have one-fourth the resistance of the original. Therefore the current increases four times to 2.0 A on 15 V and the power dissipated increases abut four times to near 30 W (same as a good, small soldering iron). Ignoring inductance, power is computed as P = I * I / R. Therefore the rewound coil will get much hotter. Two of the good members of Atlantic Coast S Gaugers approached the accessory coil overheating problem a different way. Calvin and Ted are trying time-delay relays which inhibit operation of the device more often than once every 20 seconds or so. The result is that Gabe may climb to the top once, slide down, and must stand for 15 seconds before another ascent. Or the barrel loader may load four barrels, then take a 30 second break. Hope this helps. Cheer`S' Rhett S-Trains list sponsor: http://www.americanflyertrains.com All the Flyer you desire...books and accessories too! To UNSUBSCRIBE from this list send a note to [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
