I'm in the process of upgrading the wiring on my layout. Does anyone use fuses for their animation wiring? I don't think I need them for the trains as it's just simple block wiring with an MRC Tech 4 pack (no dcc, yet). But since I am installing several animation circuits that will be used for lighting all of the structures, street lights, trolley, etc (separate power packs will be used as needed) I've begun thinking about fuses. Should I install a fuse in each circuit? Or maybe one master fuse for each power pack? If fuses are needed then what rating of fuse should I use? I've never used fuses before in layout wiring, but then again I've never had this much lighting, animation, etc. Any helpful suggestions or advice would be appreciated. Merry Christmas!
Akers, I have to ask a question: what are you trying to protect--the powerpacks or the circuits? Most $20 power packs of recent years, if they are UL-listed, can protect themselves from overloads. If you are trying to protect components in a circuit, then your fuse has to blow before your "weakest" component burns up. I'm no EE, so maybe someone else can step up?
Mark: Power Supplies have overload protection already wired into the power supplies. It isn't something you have to worry about. Stay cool and run steam.....
Not to worry, Mark, as Bob says. I do recommend a capacitor-discharge supply for switch machines. It provides more snap with a quick burst of power, and prevents the machines from burning out if a controller gets stuck. The above table machines make a miniature mushroom cloud when they blow. I know this from experience, before I built such a supply about 25 years ago. I never blew another switch machine. I did not use a fuse in my turntable drive, as it's powerful enough to turn (i.e., wreck the bridge) even if something jams. I think a fuse would not protect bulbs from burning out, although a properly-sized resistor may be needed to lower the voltage to the bulbs or LEDs rating. A fuse might protect an animation motor, which draws more current if it gets overloaded. But I'm not sure this is really feasible with the very small motors we typically use in n scale. The only motors I've ever fried in engines were the ones in the old (1970s) Atlas 0-8-0s. It's been about 20 years since I tried to apply Ohm's law to this type of problem, so I don't have a clue any longer about sizing fuzes or resistors (I just ask my older brother, who was DEC's power supply wizard for many years). I haven't played much with the Mabuchi FF-30s I bought a few years ago to repower the old Atlas 0-8-0s and perhaps to add some animated features. I doubt I'd bother to fuse them, as the Mabuchis were about $2 apiece.
On the first layout I built I had a bank of the Atlas switch control levers along the top of my control panel. They were supposed to return to center null position after the switch was thrown but sometimes they would stick. I found it very hard to collect all the smoke and get it all back into the switch motor to work again so became very good at rewinding the coils. The melted plastic housings were another matter. I split some large soda straws and painted them black to replace the blob that resulted from the stuck control switch.
Isn't rewinding the coils on a motor very hard to do? Could you rewind the coils or repair a smaller motor like on in an N scale engine? In the case of an N scale motor, wouldn't it be easier to send the motor back for warranty repair? [ 23. December 2004, 23:45: Message edited by: sapacif ]
The old 1960s era Atlas switch motor was very simple. Basically a hollow tube with a coil of wire wound around each end to make a double ended electromagnet. Energize one coil and an iron slug would slide inside the tube to that end. The slug was in turn attached to the throw lever that would move the points. When they would smoke, the wire would usually burn the enamel off the wire and short out. I would just salvage some wire off an old transformer that was about the same gauge and put enough turns on the coil to give it the same resistance as a good factory coil. As for warrantees, I was just a dumb kid and figured it was my fault the thing burned up in the first place.
For three weeks in summer 1968, I wound armatures (about 20 at a time on a stick) for GE clocks in Ashland, MA. Believe me, there was no science involved. My sole instruction from the foreman was "When the wire gets to about, see here, this point, then stop." I presume 5 % or so was good enough. I did get distracted one day, and made a baseball bat.
