Can i use a lionel transformer on an HO layout(just to power the acc)?
Thanks
Sure. As I recall, everything that comes out of a Lionel transformer is AC, so you would need a rectifier to power HO trains (DC) with it. For accessories, though, AC is generally fine. It will work for light bulbs (incandescent) and twin-coil switch machines. (I don't know about Tortoises - anybody else?)
AC will also work for LEDs, even though they are DC devices. The LEDs will be off for half their cycle, when the AC voltage is the wrong way, but they will still work. LEDs, of course, require a current-limiting resistor in series with them, regardless of what kind of power supply you're using. Some people have reported that LEDs don't last as long on AC. I haven't personally noticed any failures from this, though.
It takes an iron man to play with a toy iron horse.
Tortoise machines require DC, so running them off a Lionel transformer would require a couple of diodes. Wire one wire from each machine to one AC terminal on the transformer. Connect two diodes to the other terminal, polarity opposed. The other ends of the diodes connect to the outer poles of the SPDT switches used to control the tortoises.* One wire from the center pole of the switch to the tortoise completes the circuit.
If the Tortoise buzzes, connect a small non-polarized capacitor across the two poles of the machine.
* Which polarity of DC connects to each end of each panel switch will have to be determined individually, since Tortoise mountings are variable. The switch should indicate which way the points are thrown/which route has been selected.
Chuck (modeling Central Japan in September, 1964)